More people are catching coronavirus a second time, heightening long COVID risk, experts say

Authors: Rong-Gong Lin II, Luke Money Mon, August 1, 2022  LA Times

Emerging evidence suggests that catching the coronavirus a second time can heighten long-term health risks, a worrisome development as the circulation of increasingly contagious Omicron subvariants leads to greater numbers of Californians being reinfected.

Earlier in the pandemic, it was assumed that getting infected afforded some degree of lasting protection, for perhaps a few months.

As the coronavirus mutates, though, that’s no longer a given. And each individual infection carries the risk not only for acute illness but the potential to develop long COVID.

“The additive risk is really not trivial, not insignificant. It’s really substantial,” said Dr. Ziyad Al-Aly, clinical epidemiologist at Washington University in St. Louis and chief of research and development at the Veterans Affairs Saint Louis Healthcare System.

According to a preprint study examining U.S. veterans, of which Al-Aly was the lead author, getting infected twice or more “contributes to additional risks of all-cause mortality, hospitalization and adverse health outcomes” in various organ systems, and can additionally worsen risk for diabetes, fatigue and mental health disorders.

“Reinfection absolutely adds risk,” Al-Aly said. The study suggested that, compared with those infected only once, individuals who caught the coronavirus a second time were at 2½ times greater risk of developing heart or lung disease and blood clotting issues. Subsequent infections also were associated with a higher risk of potentially serious health problems, as well as death from COVID-19.

It’s possible that a repeat coronavirus infection will leave someone just fine, which is what happens to most people, Al-Aly said. “But you might be one of the unlucky ones and … get some really serious health problem with an infection.”

Los Angeles County Public Health Director Barbara Ferrer recently cited Al-Aly’s pre-print study as rationale for wearing masks in indoor public settings to avoid reinfection.

“They also saw that those with repeat infections had a higher risk of gastrointestinal, kidney, mental health, musculoskeletal and neurologic disorders, as well as diabetes,” Ferrer said of the study. “Moreover, the risk of developing a long-term health problem increased further with each reinfection. The risk of having long-term health conditions was three times higher for those infected compared to those who were uninfected.”

Older viruses, such as those that cause measles and chickenpox, are quite stable — meaning that the vaccinations are highly effective and surviving either illness typically confers lifelong immunity.

Not so with the coronavirus, which has mutated wildly since the pandemic began. Someone who got infected with the variant that dominated California in late 2020, for instance, was vulnerable to catching the Delta variant the following summer. And those who survived Delta faced the risk of catching the later Omicron variant.

But the reinfection landscape has been upended even further as California has been walloped with a family of increasingly transmissible Omicron subvariants. The most recent of those, BA.5, has shown particular proficiency for reinfection — with the ability to target even those who survived an earlier Omicron case mere weeks before.

“This concept of building immunity, it really only works if you’re encountering the same beast again and again and again,” Al-Aly said. But in the world of COVID-19, BA.5 is actually a “very different beast” than earlier variants.

It’s possible that the acute phase of a second bout of COVID-19 could be milder than the first. But a subsequent attack can still leave more extensive cumulative damage to the body than if there had been only one infection.

Think of coronavirus infections like earthquake sequences: It’s possible an aftershock could be less severe than the first temblor but cumulatively could add more damage. And just because your home is still standing after one quake doesn’t mean you shouldn’t explore ways to make it seismically safer.

“Part of the reason why things, for many people, feel like they’re not so bad right now is because we are being very aggressive in countering the virus with vaccines, with treatments,” Dr. Ashish Jha, the White House COVID-19 response coordinator, said during a healthcare summit hosted by the Hill. “If we took our foot off the pedal, we’re going to see this virus come back in a way that’s much more dangerous. So we’ve got to stay on that front footing and continue fighting this thing.”

As it relates specifically to long COVID — a condition in which symptoms can persist months or even years after an initial infection — getting vaccinated and boosted likely reduces risk, but studies differ as to the degree of protection.

“I think having some preexisting immunity — whether it’s natural or from a vaccine — appears to reduce your risk of long COVID, but it’s still there. It’s not zero,” said Dr. Steven Deeks, a professor of medicine at UC San Francisco and principal investigator of the Long-term Impact of Infection With Novel Coronavirus, or LIINC, study.

Another report, observing triple-vaccinated Italian healthcare workers who weren’t hospitalized for COVID-19, found that two or three doses of vaccine were associated with a lower prevalence of long COVID.

A separate report suggested that even adults who had received a booster dose still have to consider the risk of long COVID. A British report said that, during the initial Omicron wave, about 1 in every 25 triple-vaccinated adults self-reported having long COVID three to four months after their first infection.

Still, some clinicians say that long COVID sufferers tend to be either unvaccinated or missing their boosters.

“The number of patients I’m seeing who were vaccinated and boosted who are coming in with long COVID is very low,” said Dr. Nisha Viswanathan, director of the UCLA Health Long COVID Program.

Long COVID also doesn’t prevent you from becoming infected with the coronavirus again. Viswanathan said she’s had patients who have seen their long COVID symptoms improve, then get sickened with another bout of COVID-19, and then see long COVID signs return.

The best way to prevent long COVID is to not get COVID-19. Many officials and experts cite non-pharmaceutical interventions such as masking as key tools, since vaccinations reduce, but do not entirely eliminate, the risk.

Masking is not a terrible thing to ask of people, especially in probably the places that are the most crowded, and the places that maybe are the highest risk of transmission,” Viswanathan said. Taking activities outside is also safer than being unmasked indoors.

Some of Viswanathan’s patients have downplayed the risk of COVID-19, commenting how it’s become a mild illness, and adding they don’t see the point of taking precautions. But, she said, better knowledge about long COVID and its disabling effects would help people understand the importance of masking and getting vaccinated and boosted.

A UCLA study published in the Journal of General Internal Medicine, of which Viswanathan was a co-author, found that of 1,038 patients with symptomatic COVID-19 between April 2020 and February 2021, nearly 30% developed long COVID. The most common symptoms were fatigue and shortness of breath among hospitalized patients.

While many are weary of COVID-19 preventive measures after nearly two and a half years, they remain important, said Dr. Anne Foster, vice president and chief clinical strategy officer for the University of California Health system.

The burden of long COVID following this wave is unknown. The official case tallies are likely vast undercounts, given that so many at-home tests are being used, and that could suggest that the burden of long COVID in subsequent months will be hard to predict, Foster said.

“I know everyone has moved on and people are going back to the way things were, and I sort of get it,” Deeks said. “But people do need to be aware that there is this additional risk that’s not going away and they might adjust their lives accordingly.

“But everyone’s going to figure this out on their own.”

Why Are So Many People Getting COVID a Second and Third Time?

Doctors say if you got infected with the Omicron BA.1 or BA.2 variants, your antibodies might not fully protect you against the newer BA.4 and BA.5 subvariants now spreading through Southern California

Authors: Joel Grover and Josh Davis  June 16, 2022 NBC News

A sign encouraging mask use hangs on a fence before the local school council and the Chicago Teachers Union held a press conference Tuesday, Sept. 28, 2021 outside Jensen Elementary School in Chicago’s North Lawndale neighborhood. (Brian Cassella/Chicago Tribune/Tribune News Service via Getty Images)

Just days after Congresswoman Maxine Waters attended the Summit of the Americas in downtown LA last week, she tested positive for COVID-19. It was the second time in less than two months Waters has tested positive.

Until recently, many people who got COVID-19 thought they had months or years of protection from getting it again. But researchers tell the NBC4 I-Team that’s not the case.

“I’m not surprised to see people testing positive a second and third time,” says Dr. Saahir Khan, an infectious disease expert at USC’s Keck School of Medicine.

“The virus is mutating very quickly,” Dr. Khan told NBC4.

Doctors like Khan say if you got infected with the Omicron BA.1 or BA.2 variants, your antibodies might not fully protect you against the newer BA.4 and BA.5 subvariants now spreading through Southern California.

“As the virus mutates more and more, the antibodies to the prior variants give less and less protection over time,” Dr. Khan says.

But public health experts say second and third infections are often very “manageable.”

“The thing about these reinfections, is they get increasingly milder. Much less likely to even cause you to call your doctor,” says Dr. Amesh Adalja of Johns Hopkins Bloomberg School of Public Health.

So how soon can you get COVID for a second or third time, after a previous infection?

U.S. Health and Human Services Secretary Xavier Becerra tested positive this past Monday, less than a month after his first positive test.

“I wouldn’t say there’s a hard and fast timeline when you can get reinfected. It’s just that your protection wanes over time, over the course of a few months,” says Dr. Khan at USC.

Public health experts say the vaccines that are now available might not prevent reinfection by newer variants, but a new class of vaccines that could be out by this fall could provide wider protection.

“COVID is spread through the air, particularly in indoor spaces where people share the same air. And so what you can do to prevent reinfection is wear a mask indoors, particularly in a high risk situation where a lot of people congregate, like airports and grocery stores, Dr. Khan told the I-Team.

More of the vaccinated and boosted landing in hospital with COVID-19

Authors: By Ariel Hart Zachary Hansen May 19. 2022 – The Atlanta Journal-Constitution

Doctors say it’s caused by a combination of a variant that can escape the vaccine’s effects and the most vulnerable also being the most vaccinated

As summer once again brings signs of a coming COVID-19 wave, an unusual trend has emerged: The Georgians who are fully vaccinated and boosted are increasingly winding up in the hospital with serious COVID-19 symptoms.

The phenomenon points to two changes in the unpredictable pandemic battleground more than two years in. The circulating omicron variant has become better at evading the vaccine, which was designed on the first version of coronavirus to appear in China. And the people most likely to get boosted are those who were most vulnerable to begin with: the elderly, or patients with pre-existing conditions. Despite the extra vaccine protection, those people remain the most vulnerable.

Even in light of the unexpected hospitalizations of those vaccinated and boosted, doctors say it’s still true that boosted groups are the least likely to die.

“I’ve had several older patients who have been boosted and had the vaccine,” said Dr. William Cleveland, a nephrologist in southwest Atlanta. “They get hospitalized, and they had to have some significant medical attention, but they get discharged. And I know that just because of their frailty, without having had the vaccine they would not have survived.”

The rate of hospitalizations for boosted Georgians fell again this week, but still remains higher than the rate of hospitalizations for those with only the primary vaccine series (2 shots). The fact that boosted patients’ hospitalizations nearly outstripped all others even for one week was an unprecedent moment in the pandemic. In the past, hospitalization rates for unvaccinated groups have drastically outnumbered those who have taken the vaccine — sometimes tenfold.

The trend emerged at the tail-end of the omicron variant outbreak and has accelerated over the past two months, setting off alarm bells for state public health experts already expecting a surge in cases this summer.

Dr. Eva Lee, director of the Center for Operations Research in Medicine and Healthcare at Georgia Tech, agreed that the rate of hospitalizations among boosted people was on track to outpace other populations. However, she said it’s not a sign of vaccines losing all effectiveness — it has to do with who is choosing to get boosted.

“A big part of the people that are boosted are also the ones that are really at high risk already to begin with, right?” Lee said. “But what has remained and hasn’t changed is the following: The people that are at risk remain at risk. That means the people that are immune-compromised and the people that are like the elderly people, and people who have coexisting conditions, their risk is still higher.”

Growing number of breakthroughs

Overall, the number of people hospitalized with COVID remains at or near the lowest rate since the beginning of the pandemic. But state data shows that the most protected and least protected groups are starting to find themselves fighting for their lives in Georgia hospitals at nearly the same levels.

According to Georgia Department of Public Health data, unvaccinated groups were being hospitalized due to COVID at twice the rate of other populations at the beginning of March. By the end of April, there were 1.3 hospitalizations per 100,000 vaccinated and boosted Georgians compared to 1.6 hospitalizations for every 100,000 unvaccinated Georgians.https://datawrapper.dwcdn.net/qtaSR/1/

In addition to at-risk groups being more likely to get every shot available to them, omicron and its subvariants have presented a challenge for the U.S.’s current vaccines. Breakthrough cases of less serious illness are now common, and health experts warn they are a sign of the vaccines’ waning immunity.

“Prior to Omicron we could, with a booster, assume there was well over 90-95% vaccine effectiveness vs severe disease,” Eric Topol, founder and director of the Scripps Research Translational Institute in New York, wrote in a recent column sounding the alarm for a summer surge in COVID-19 infections. “It is clear, however, from multiple reports … that this level of protection has declined to approximately 80%, particularly taking account the more rapid waning than previously seen. That represents a substantial drop-off.”

The growing number of breakthrough cases has prompted national health officials to discuss reformulating the current vaccines to specifically target omicron and its subvariants. The U.S. Food and Drug Administration has a meeting scheduled for June 28 to evaluate vaccine efficiency and composition.

Georgia hasn’t seen any noticeable uptick in COVID-19 deaths, but death reports often lag behind increasing hospitalization rates by several weeks.

While health experts are troubled by the rising hospitalization rates, they emphasize that COVID’s death toll would already be on the rise if the most at-risk Georgians weren’t vaccinated and boosted.

Surprised to still be alive

Raymond Fain knew he couldn’t risk getting COVID-19. Given he has kidney disease, the 58-year-old made sure to not only get fully vaccinated but he took a Pfizer booster shot to boot.

Just two months later, during the onslaught of the omicron variant this winter, he was shocked to be told that in spite of his vaccinations he caught COVID. What followed was a bad sickness and two rounds of hospitalization that totaled nearly a month. But at the end of it, came another surprise: He lived.

“I was sort of shocked that that disease that I caught didn’t overcome me with, the failed kidneys. You know what I’m saying?” Fain said.

Cleveland works with Fain’s doctor, both of whom have pleaded with their kidney patients to get vaccinated. Cleveland is all too familiar with kidney patients who get COVID and don’t make it. He’s heard all the excuses, and he’s ready to counter them.

“I’ve seen so much of that (kidney patients succumbing to COVID) that I do not hesitate to try to explain to my patients that I’ve just seen this too many times to to be comfortable with them saying that they are afraid,” Cleveland said.

The percentage of Georgia residents who’ve been vaccinated is among the lowest in the country — the peach state currently ranks 45th. The state’s booster adoption rate is even worse, with less than half of all fully vaccinated people choosing to get one booster dose.

There’s also a large age disparity among those getting boosted. Nearly 60% of all Georgia seniors, people 65 and older, have gotten a booster dose, but there’s a stark drop-off for younger populations. Only about 15% of 25- to 34-year-old Georgians are boosted.

The low booster adoption rate for younger people, who are less likely to be at a high risk of life-threatening infections, is an explanation for why boosted groups seem to be hospitalized at higher rates, health experts said.https://datawrapper.dwcdn.net/KYHdI/1/

“All such people need to have vaccination and booster coverage but our (Centers for Disease Control and Prevention) has failed to convey their life-saving impact from the get go…” Topol wrote in his column. “That’s why we have 31% of Americans who had had 1 booster shot whereas most peer countries are double that proportion.”

For Fain, he’s surprised he was able to pull through his severe bout with COVID and get back on his feet, but his friends and loved ones haven’t let him forget how close he was to death.

“Everybody’s going to talk to me now, they say, ‘Boy when you started, we thought you was going to get gone. You sounded so bad,’” Fain said. “Yeah, but everything is okay now. I’m strong.”

How many times can you get COVID? What experts know about reinfection

Authors:  Hannah Sparks May 18, 2022  The New York Post

The new normal is now.

In what seemed like an instant, COVID-19 became an inevitable aspect of everyday life more than two years ago — with no signs to suggest that we’ll ever see otherwise again.

As we look at our lives ahead with waves of new variants and “stealth” sub-variants, and seasonal vaccine boosters to match, it begs the question: Should we fear reinfection?

Doctors have recently confirmed that those infected with an earlier Omicron variant, which first appeared and spread rapidly last summer, can indeed test positive again for the new sub-variant.

Last week, as the latest strain — BA.2 or BA2.12.1 — made its presence known in New York City and clusters throughout the Northeast and Midwest, the US crossed a grim milestone: 1,000,000 COVID deaths. Globally, we’ve lost more than 6,000,000.

The Post spoke to NYU Langone Health infectious diseases expert Dr. Michael Phillips about what we can expect from life with COVID as we know it.

Can you get infected with COVID twice — and who’s at risk?

There is no such thing as perfect immunity from COVID. Regardless of severity or immunization, someone who tests positive for the virus can become infected again at some point.

“Our hospitalizations have crept up over the past several weeks, particularly with this newer variant of Omicron,” Dr. Phillips told The Post. “But thankfully, the vast majority of people [who] get the infection tend to recover without too much problems.”

But there’s more at stake for some. People who have not received two doses of the mRNA vaccine, as well as those with weakened immune systems due to age, medications, preexisting illness or other clinical factors, such as poor physical fitness, are at a higher risk of reinfection and becoming severely sick with COVID-19.

But Phillips warns against us “develop[ing] a laissez faire attitude about it.” While some relatively young, healthy and vaccinated individuals may become reinfected with only a mild case, the person they pass it to — potentially, someone with a weakened immune system due to age, medications, preexisting illness or other clinical factors, such as poor physical fitness — may not fare so well.

Omicron is “very, very different from prior waves of Delta,” Phillips added. “I think it shifted our game plan for sure.” Now more than ever the focus of prevention efforts is on protecting those the ones at a greater risk of severe illness — and protecting yourself from COVID reinfection means also “protect[ing] the vulnerable.”

Can you be reinfected with the same COVID variant?

It’s certainly possible, particularly in those who are not vaccinated. Unlike earlier variants, Omicron has rapidly evolved into several sub-types, prompting simultaneous localized outbreaks. Meanwhile, there’s no telling how many positive cases of COVID-19 go unreported, whether due to lack of testing or symptoms to warrant alarm. So whether to fear reinfection with the same niche strain may not be a pragmatic question to ask — because, by the time it’s answered, a new strain may already be here.

“There are so many of these other variants within that big family of coronaviruses, and we’re typically infected with three to four a year,” Phillips explained, most of which present as a mild cold.

Ideally, SARS-CoV-2 could fade into coronavirus obscurity like many of the others — but we aren’t there yet, and it’s too soon to say whether that’s a feasible outlook. “It’s still severe enough that that we have to be pretty mindful about,” said Phillips. “We just don’t know enough about future variants for us to take our guard down yet.”

How long after getting COVID can you be reinfected?

This is another complicated question — especially for sufferers of long COVID, who appear to harbor low, even undetectable levels of the virus for weeks and months. For mild to moderate cases, people who test positive for COVID can expect their infection to clear within five to 10 days after their symptoms arose, or since their confirmed test result.

Nascent research suggests that the average immune system can fend off COVID reinfection for three to five months after the previous bout. That’s why, according to the Centers for Disease Control and Prevention, people who had a confirmed infection within the previous 90 days are not expected to quarantine after coming in contact with another infected individual.

But all bets are off about six months later, when antibodies are known to start waning — regardless of vaccination.

How long do COVID antibodies last?

Experts don’t know exactly. While those survive COVID appear to be largely protected from repeat or severe illness for up to five months after the previous infection, there isn’t enough data available yet to be certain how long those COVID-specific antibodies linger, or even to confirm that the presence of antibodies guarantees immunity, according to the Food and Drug Administration.

Immune system B cells give rise to COVID-specific antibodies, designed to attack the virus on sight, before it can penetrate tissue cells and reproduce. They begin to form within the first few days infection or vaccination, and continue to build for several weeks until they peak at around three months thereafter — when your COVID defenses are at their strongest.

The good news is that waning antibodies doesn’t mean we’re totally defenseless, as some B cells will remember the tools it previously took to create COVID antibodies during re-invasion. (Boosters, furthermore, helps our immune system remember how. to fight.) Meanwhile, our killer T-cells, the immune system’s backup line of defense, may not so good at preventing the virus from entering the body, but they can spot an infected host cell — and destroy before it multiplies to another cell. And while they’re more difficult to track, they do appear to be more faithful than fleeting antibodies.

“Those appear to stay be much more robust,” said Phillips, adding, that “the T cell response is probably more important for response to viral infections” in the long run.

Are COVID vaccines still effective?

“We don’t have to be paranoid about the emergence of a new strain … but we have to be thoughtful and ready for that.”

Dr. Michael Phillips, MD, NYU Langone Health

More or less. Vaccines remain the best way to build-up antibodies, the body’s primary line of defense against severe COVID-19 illness. While allowing oneself to become infected can also give rise to antibodies, it’s not worth the risk.

“I’m strongly pro vaccine, because of the the problems that happen when you don’t get it,” said Phillips, who hinted at alternative forms of vaccination technology on the horizon as well.

Regardless of type, antibodies are known to wane afer about six months since last infection or booster, making reinfection more likely to occur.

How often can you get a COVID booster?

For those on the two-dose regimen, a second round should be completed about six weeks after the first. However, it’s been well over a year since the vaccine was introduced, which means many patients completed those two rounds back in 2021.

Doctors expect that annually, even seasonally redesigned boosters against COVID-19 could become the norm — kind of like influenza, only different, and more troubling: One flu season sees just one or two major strains globally, allowing researchers time to prepare vaccines. “It’s not this, sort of, constant changing during a ‘season’,” said Phillips, like COVID-19 has done.

Currently, only those who have a weakened immune system and people age 50 or older are being recommended for a third shot by the CDC — which is, altogether, a good sign.

Said Phillips, “We don’t have to be paranoid about the emergence of a new strain … but we have to be thoughtful and ready for that.”

Had Covid At Christmas? You Could Get It Again Now

Authors: Madison Muller, May 13,2022 Bloomberg News

As a stealth wave of Covid makes its way across the U.S., those who have so far evaded the virus are now falling ill — while others are catching Covid for a second, third or even fourth time.Several factors have conspired to make the state of the pandemic harder than ever to track. The rise of at-home tests, which rarely make it into official case numbers, have made keeping accurate count of positive cases impossible. Additionally, many U.S. states and jurisdictions are now reporting Covid data only sporadically to the Centers for Disease Control and Prevention. Earlier this week, Washington, D.C., reported case data to the agency for the first time since April.This has happened just as new, more contagious subvariants of omicron are making their way through the U.S. population, leading not only to rising first-time Covid cases but also frequent reinfections. The latest versions of the virus appear particularly adept at evading the body’s immune response from both past Covid infections and vaccines. Studies suggest most reinfection cases aren’t even being reported, giving little insight into how often they occur. All this makes it especially difficult to gauge what percentage of the population is presently vulnerable to Covid — and how the pandemic might evolve. “The reality is that things are really not going well at the moment,” said Jacob Lemieux, an infectious disease doctor at Massachusetts General Hospital, speaking at a Harvard Medical School Covid briefing on Tuesday. “We all thought that we were in for a reprieve after the devastating omicron wave. And that was clearly the case until a few weeks ago.”The result is that coworkers are calling in sick, friends are posting snapshots of positive Covid tests on social media and school contact tracing programs are blasting out exposure alerts, even as official Covid case counts suggest the numbers are only creeping back up slowly. On Tuesday, the CDC reported more than 98,000 new cases. The true number is almost certainly higher. “There’s so much less visibility about what’s happening,” said Rick Bright, a virologist and CEO of the Rockefeller Foundation’s Pandemic Prevention Institute.Experts say that it’s difficult to know what the next few months will bring. While vaccines are still doing a good job at keeping most people out of the hospital, the virus is not behaving the same way it has in the past and the majority of the country is living like the pandemic is over. In December and January, during the first wave of omicron infections, case levels skyrocketed before dropping almost as quickly. That’s because widespread infections at the start of the outbreak soon gave the virus fewer people to infect. Public health measures, like masking, also helped reduce the spread. That may not be what happens this time.

“It’s likely that we won’t see the same fast downturn of cases we’ve seen in other surges,” said Bob Wachter, chief of medicine at the University of California, San Francisco.Early evidence suggests omicron has not only made Covid reinfection more likely, but also shortened the window in which a past infection provides protection against the virus. There was hope that the hundreds of thousands of omicron infections this past winter would help bolster population immunity and protect against future surges in coming months. According to CDC data, about a third of the country had caught Covid prior to the omicron wave, a figure that has since increased to more than half. But how effective those antibodies are is now dependent on what variant a person gets.

Delta immunity, for example, doesn’t hold up well against other variants, according to a study recently published in Nature. And there is now evidence that some omicron subvariants can even evade the immune defenses imparted by omicron variants that came before them. One recent study published as a preprint by researchers in Beijing found that several omicron subvariants—BA.2.12.1, BA.4 and BA.5—could get past the defenses of immunity from infection with another version of omicron, BA.1.

All of these factors mean that huge swaths of the population once protected from infection may now be vulnerable.There are just too many holes in the data to be able to judge the state of the pandemic accurately. It’s unclear how frequently reinfections are occurring or which variants people are getting reinfected with. The CDC’s last update on reinfections was in January. The agency has not indicated whether it is tracking the cases and does not make such data available to the public.A handful of state health departments, though, have taken to diligently monitoring the repeat cases. That data suggests reinfections are now happening more frequently.The Colorado State Health Department, for example, has recorded more than 44,000 reinfections throughout the pandemic — 82% of which have occurred since omicron became the dominant variant in December. Reinfections are more common among the unvaccinated, but more than a third have happened to people who have completed their initial two-dose vaccine series, according to the data. Over 16% of reinfections in Colorado have been in people with at least one booster dose.Data from the North Carolina Department of Health and Human Services show reinfections in the state have been increasing since late March. Reinfections currently make up 8% of the state’s total infections for the week ending April 30. Repeat infections have been on the rise in Indiana, too, according to data, where they account for more than 12% of total cases, and in Idaho where they accounted for 18.5% of cases in the first quarter of 2022.A report from Washington state published Wednesday shows that some reinfections are also leading to hospitalization. The age group most likely to get reinfected is 18 to 34 year olds, but people 65 and older are the most likely to get hospitalized after reinfection, the data show.“It feels like the first time in two years that no matter if someone is really careful and does everything right, it won’t be surprising if they end up getting Covid,” said Wachter, at University of California, San Francisco. “We’re unquestionably in a surge.”

Coronavirus wave this fall could infect 100 million, administration warns

Authors: Yasmeen Abutaleb, Joel Achenbach May 6, 2022 The Washington Post

The Biden administration is warning the United States could see 100 million coronavirus infections and a potentially significant wave of deaths this fall and winter, driven by new omicron subvariants that have shown a remarkable ability to escape immunity.

The projection, made Friday by a senior administration official during a background briefing as the nation approaches a covid death toll of 1 million, is part of a broader push to boost the nation’s readiness and persuade lawmakers to appropriate billions of dollars to purchase a new tranche of vaccines, tests and therapeutics.

In forecasting 100 million potential infections during a cold-weather wave later this year and early next, the official did not present new data or make a formal projection. Instead, he described the fall and winter wave as a scenario based on a range of outside models of the pandemic. Those projections assume that omicron and its subvariants will continue to dominate community spread, and there will not be a dramatically different strain of the virus, the official said, acknowledging the pandemic’s course could be altered by many factors.

Several experts agreed that a major wave this fall and winter is possible given waning immunity from vaccines and infections, loosened restrictions and the rise of variants better able to escape immune protections.

Many have warned that the return to more relaxed behaviors, from going maskless to participating in crowded indoor social gatherings, would lead to more infections. The seven-day national average of new infections more than doubled from 29,312 on March 30 to nearly 71,000 Friday, a little more than five weeks later.

“What they’re saying seems reasonable — it’s on the pessimistic side of what we projected in the covid-19 scenario modeling run,” said Justin Lessler, an epidemiologist at University of North Carolina Gillings School of Global Public Health. “It’s always hard to predict the future when it comes to covid, but I think we’re at a point now where it’s even harder than normal. Because there’s so much sensitivity, in terms of these long-term trends, to things we don’t understand exactly about the virus and about [human] behavior,” Lessler said.

Another modeler, epidemiologist Ali Mokdad of the University of Washington’s Institute for Health Metrics and Evaluation, said in an email Friday that a winter surge is likely. His organization, which has made long-term forecasts despite the many uncertainties, just produced a new forecast that shows a modest bump in cases through the end of May and then a decline until the arrival of winter.

Another rare virus puzzle: They got sick, got treated, got covid again

Authors: Carolyn Y. Johnson  April 27, 2022 The Washington Post

Shortly after he served on a jury in March, Gregg Crumley developed a sore throat and congestion. The retired molecular biologist took a rapid test on a Saturday and saw a dark, thick line materialize — “wildly positive” for the coronavirus.

Crumley, 71, contacted his doctor two days later. By the afternoon, friends had dropped off a course of Paxlovid, a five-day regimen of antiviral pills that aims to keep people from becoming seriously ill.

The day he took his last dose, his symptoms were abating. He tested each of the next three days: all negative.

Then, in the middle of a community Zoom meeting, he started feeling sick again. Crumley, who is vaccinated and boosted, thought it might be residual effects of his immune response to the virus. But the chills were more prolonged and unpleasant. He tested. Positive. Again.

Crumley, like other patients who have experienced relapses after taking Paxlovid, is puzzled — and concerned. On Twitter, physicians and patients alike are engaged in a real-time group brainstorm about what might be happening, with scant evidence to work with.

It is the latest twist — and newest riddle — in the pandemic, a reminder that two years in, the world is still on a learning curve with the coronavirus.

Infectious-disease experts agree that this phenomenon of the virus rebounding after some patients take the drug appears to be real but rare. Exactly how often it occurs, why it happens and what — if anything — to do about it remain matters of debate.

What’s clear is that patients should be warned it is possible so they don’t panic — and so that they know to test again if they start feeling ill. More data is needed to understand what is going on. Paxlovid, made by the drug giant Pfizer, remains a useful drug, even though it has sparked a new mystery.Biden administration boosts access to antivirals as covid cases rise

“I’m not negative on Paxlovid,” said Crumley, who lives in Philadelphia and whose last positive test was a week after his second wave of illness began. “I don’t know whether it’s just stopping [viral] replication for that five-day period of time, and it comes back.”

One of the top worries accompanying antiviral drugs is the threat of resistance, when the virus evolves to evade the treatment. A Food and Drug Administration analysis of Pfizer’s clinical trial of the drug showed the virus rebounded in several subjects about 10 to 14 days after their initial symptoms but found no reason and no evidence that their infections were resistant to the treatment.

Michael E. Charness, chief of staff at the VA Boston Healthcare System, published a detailed case study of one 71-year-old patient who had a relapse. The man, who was vaccinated and boosted, received Paxlovid and quickly felt better. When he developed cold symptoms a week after his case of covid had resolved, researchers sequenced the virus’s genetic code and found it was the same virus surging back. That ruled out a reinfection, the emergence of a variant or the virus becoming resistant.

Charness would like to see more data and other questions answered. Should antivirals be given longer, to assure the virus is cleared? Should people be treated a second time? What are the implications for people returning to their normal lives?

“If you have a resurgence of viral load, and that happens on day 10, when CDC says you’re back to work, no mask, what are you supposed to do about isolation? Is that a moment when you’re contagious again?” Charness said. “The person we studied, we advised to isolate until their viral load was gone the second time.”

Pfizer is collecting data, in clinical trials and in real-world monitoring of the drug’s use. The company’s trial data indicates there is a late uptick in viral load in “a small number” of people who take the drug, but the rates appear to be similar among study participants given a placebo, according to company spokesman Kit Longley. The people who experienced such increases also did not develop severe disease the second time around.

Those findings suggest that Paxlovid isn’t the reason people are relapsing, because that’s happening in untreated people, too.

If that turns out to be true, it raises the concern that some people — whether they have taken the drug or not — could be infectious long after they think they are in the clear, and after guidelines suggest they can stop taking precautions.

“Although it is too early to determine the cause, this suggests the observed increase in viral load is unlikely to be related to Paxlovid,” Longley wrote in an email. “We have not seen any resistance to Paxlovid, and remain very confident in its clinical effectiveness.”

The limited evidence leaves most physicians favoring the idea that Paxlovid knocks the virus down but doesn’t knock it out completely. It’s possible that by holding the virus in check, the immune response doesn’t fully ramp up, because it doesn’t see enough virus. Once the treatment ends, the virus can start multiplying again in some people.

Philip Bretsky, a primary care doctor in Santa Monica, Calif., said he has encountered two cases among patients, both of whom were vaccinated and boosted at least once.

A double-boosted 72-year-old who had chronic medical conditions that raised his risk for severe illness started to feel unwell at the end of March. He tested positive and began a course of Paxlovid. He felt better and tested negative. Then, 12 days later, he started feeling crummy again — and tested positive.

Reinfection seemed improbable, and Bretsky thought resistance was unlikely with a five-day course of treatment.

In well-vaccinated people, being reinfected so quickly would be “like getting struck by lightning or winning the lottery,” Bretsky said. “I don’t think this is reinfection. I think this is recrudescence of the original infection.”

Experts don’t know how common this phenomenon is. Many people may not test if they get sick again after their initial infection has receded, making it hard to track.

That almost happened to Holly Teliska, 42, of San Francisco. Teliska got sick shortly after returning home from a trip to New York. She has a risk factor for severe illness and got access to Paxlovid right away. When she finished her treatment course, she took a home PCR test that was negative and felt much better, though remained fatigued.

Four days later, she came down with a runny nose and cough. She assumed she had caught her daughter’s cold and powered through. Five days later, with plans to visit an immunocompromised friend, she took a test.

Teliska almost felt silly testing herself. She had been vaccinated and boosted, then infected.

“We’ve been saying I’m her safest friend now, now that I’ve had covid, so for three months, I can go spend time with her pretty safely,” Teliska said. “That really threw that narrative out the window. … This entire experience has been a real reminder there is still so much to learn.”

Paxlovid is new. It only began to be used in December, so reports people share on social media of resurgent illness may be the tip of the iceberg — or might simply reflect the eagerness to learn more about a rare, intriguing outcome.

If such cases turn out to be exceedingly rare, then these case reports may be a sporadic curiosity — something to warn patients could happen. If more common, it could lead to tweaks in treatment regimens.

The mounting anecdotes are compelling to many physicians, but it’s also possible the virus might rarely rebound. Yonatan Grad, an associate professor of immunology and infectious diseases at the Harvard T.H. Chan School of Public Health, has studied the viral loads of NBA players and staff during the course of an infection. That data, he said, shows that viral loads can bounce around.

What’s “exceptionally uncommon,” Grad said, is for the viral load to plunge for a few days to a level that suggests they are negative and then go up again.

Paul Sax, an infectious-diseases specialist at Brigham and Women’s Hospital in Boston, recently shared the story of a patient who became infected and then relapsed after taking Paxlovid. He has heard from lots of colleagues with similar stories. But the anecdotes raise more questions than they answer.

Even if the virus has not been shown to develop resistance to the treatment during a resurgence, that’s doesn’t mean it won’t happen, he points out. Does the treatment knock the virus down so successfully that people aren’t generating a robust immune response? That could have implications for understanding whether being infected acts as a potent booster.

The phenomenon is so new that many doctors aren’t aware of it. Jennifer Charness, a 31-year-old nurse who lives in Brookline, Mass., had the benefit of knowing about her father’s work at the Boston VA.

Charness started sneezing in early April and got a blaringly positive coronavirus test. She has a history of asthma and was prescribed Paxlovid. As she took the drug, she saw her positive test line grow fainter and her symptoms resolve. She swabbed to make sure she was negative before going back to work, as a precaution. Then, two days later, she felt the symptoms come back and tested positive — again.

“I’m so frustrated,” Charness said. “I don’t think I’m going to get very sick. It’s the concern of what does this mean for my viral load, and how contagious am I? And when will I not be contagious? I’m stuck back in my home again.”

Charness’s primary concern is that she doesn’t pose a risk to anyone else. She consulted a doctor via telemedicine Friday. The practice hadn’t heard of any cases like hers and decided to treat it as a reinfection and reset the isolation clock.

“I’m Day 4,” she said. “Or am I Day 13?”

COVID cases rise again in half the states

Change in reported COVID-19 cases per 100k people in the last two weeks

March 23 to April 5, 2022

Half of the states are seeing COVID case numbers rise again while nationwide totals continue to fall.

The big picture: The Omicron subvariant known as BA.2 is the dominant strain circulating around the U.S., accounting for almost three out of every four cases.

By the numbers: Overall, cases dropped 5% across the U.S. to an average of about 28,700 cases from an average of more than 30,000 cases two weeks ago.

  • Three states — Alaska, Vermont and Rhode Island — had more than 20 new cases per 100,000 people.
  • Nine states — Utah, Montana, South Dakota, Kansas, Louisiana, Iowa, Arkansas, Indiana and Tennessee — had three or fewer new cases per 100,000 people.

Between the lines: Deaths fell to an average of 600 a day, down 34% from just over 900 a day two weeks ago.

What we’re watching: While U.S. officials have said they aren’t expecting a significant rise in hospitalizations or deaths, there have been signs of hospitalizations rising among older individuals in the U.K., the Guardian reported.

  • Since those numbers lag behind new cases, we won’t have a clear view of that impact in the U.S. for a few weeks.
  • The highly contagious subvariant surged through parts of Europe but probably will spare many Americans, thanks in part to this winter’s Omicron surge.

Axios on facebookAxios on twitterAxios on linkedinAxios on email

COVID-19 Cases and Hospitalizations by COVID-19 Vaccination Status and Previous COVID-19 Diagnosis — California and New York, May–November 2021

Weekly / January 28, 2022 / 71(4);125–131 January 19, 2022, this report was posted online as an MMWR Early Release.

Authors: Tomás M. León, PhD1; Vajeera Dorabawila, PhD2; Lauren Nelson, MPH1; Emily Lutterloh, MD2,3; Ursula E. Bauer, PhD2; Bryon Backenson, MPH2,3; Mary T. Bassett, MD2; Hannah Henry, MPH1; Brooke Bregman, MPH1; Claire M. Midgley, PhD4; Jennifer F. Myers, MPH1; Ian D. Plumb, MBBS4; Heather E. Reese, PhD4; Rui Zhao, MPH1; Melissa Briggs-Hagen, MD4; Dina Hoefer, PhD2; James P. Watt, MD1; Benjamin J. Silk, PhD4; Seema Jain, MD1; Eli S. Rosenberg, PhD2,3

Summary

What is already known about this topic?

Data are limited regarding the risks for SARS-CoV-2 infection and hospitalization after COVID-19 vaccination and previous infection.

What is added by this report?

During May–November 2021, case and hospitalization rates were highest among persons who were unvaccinated without a previous diagnosis. Before Delta became the predominant variant in June, case rates were higher among persons who survived a previous infection than persons who were vaccinated alone. By early October, persons who survived a previous infection had lower case rates than persons who were vaccinated alone.

What are the implications for public health practice?

Although the epidemiology of COVID-19 might change as new variants emerge, vaccination remains the safest strategy for averting future SARS-CoV-2 infections, hospitalizations, long-term sequelae, and death. Primary vaccination, additional doses, and booster doses are recommended for all eligible persons. Additional future recommendations for vaccine doses might be warranted as the virus and immunity levels change.

By November 30, 2021, approximately 130,781 COVID-19–associated deaths, one in six of all U.S. deaths from COVID-19, had occurred in California and New York.* COVID-19 vaccination protects against infection with SARS-CoV-2 (the virus that causes COVID-19), associated severe illness, and death (1,2); among those who survive, previous SARS-CoV-2 infection also confers protection against severe outcomes in the event of reinfection (3,4). The relative magnitude and duration of infection- and vaccine-derived protection, alone and together, can guide public health planning and epidemic forecasting. To examine the impact of primary COVID-19 vaccination and previous SARS-CoV-2 infection on COVID-19 incidence and hospitalization rates, statewide testing, surveillance, and COVID-19 immunization data from California and New York (which account for 18% of the U.S. population) were analyzed. Four cohorts of adults aged ≥18 years were considered: persons who were 1) unvaccinated with no previous laboratory-confirmed COVID-19 diagnosis, 2) vaccinated (14 days after completion of a primary COVID-19 vaccination series) with no previous COVID-19 diagnosis, 3) unvaccinated with a previous COVID-19 diagnosis, and 4) vaccinated with a previous COVID-19 diagnosis. Age-adjusted hazard rates of incident laboratory-confirmed COVID-19 cases in both states were compared among cohorts, and in California, hospitalizations during May 30–November 20, 2021, were also compared. During the study period, COVID-19 incidence in both states was highest among unvaccinated persons without a previous COVID-19 diagnosis compared with that among the other three groups. During the week beginning May 30, 2021, compared with COVID-19 case rates among unvaccinated persons without a previous COVID-19 diagnosis, COVID-19 case rates were 19.9-fold (California) and 18.4-fold (New York) lower among vaccinated persons without a previous diagnosis; 7.2-fold (California) and 9.9-fold lower (New York) among unvaccinated persons with a previous COVID-19 diagnosis; and 9.6-fold (California) and 8.5-fold lower (New York) among vaccinated persons with a previous COVID-19 diagnosis. During the same period, compared with hospitalization rates among unvaccinated persons without a previous COVID-19 diagnosis, hospitalization rates in California followed a similar pattern. These relationships changed after the SARS-CoV-2 Delta variant became predominant (i.e., accounted for >50% of sequenced isolates) in late June and July. By the week beginning October 3, compared with COVID-19 cases rates among unvaccinated persons without a previous COVID-19 diagnosis, case rates among vaccinated persons without a previous COVID-19 diagnosis were 6.2-fold (California) and 4.5-fold (New York) lower; rates were substantially lower among both groups with previous COVID-19 diagnoses, including 29.0-fold (California) and 14.7-fold lower (New York) among unvaccinated persons with a previous diagnosis, and 32.5-fold (California) and 19.8-fold lower (New York) among vaccinated persons with a previous diagnosis of COVID-19. During the same period, compared with hospitalization rates among unvaccinated persons without a previous COVID-19 diagnosis, hospitalization rates in California followed a similar pattern. These results demonstrate that vaccination protects against COVID-19 and related hospitalization, and that surviving a previous infection protects against a reinfection and related hospitalization. Importantly, infection-derived protection was higher after the Delta variant became predominant, a time when vaccine-induced immunity for many persons declined because of immune evasion and immunologic waning (2,5,6). Similar cohort data accounting for booster doses needs to be assessed, as new variants, including Omicron, circulate. Although the epidemiology of COVID-19 might change with the emergence of new variants, vaccination remains the safest strategy to prevent SARS-CoV-2 infections and associated complications; all eligible persons should be up to date with COVID-19 vaccination. Additional recommendations for vaccine doses might be warranted in the future as the virus and immunity levels change.

Four cohorts of persons aged ≥18 years were assembled via linkages of records from electronic laboratory reporting databases and state-specific immunization information systems. Persons were classified based on whether they had had a laboratory-confirmed SARS-CoV-2 infection by March 1, 2021 (i.e., previous COVID-19 diagnosis)§; had received at least the primary COVID-19 vaccination series by May 16, 2021; had a previous COVID-19 diagnosis and were fully vaccinated**; or had neither received a previous COVID-19 diagnosis by March 1 nor received a first COVID-19 vaccine dose by the end of the analysis period. The size of the unvaccinated group without a previous diagnosis was derived by subtracting the observed groups from U.S. Census estimates.†† To maintain each defined cohort, persons who received a COVID-19 diagnosis during March 1–May 30, 2021, or who died before May 30, 2021, were excluded (to maintain eligibility for incident cases for all cohorts on May 30, 2021),§§ as were persons who received a first vaccine dose during May 30–November 20, 2021. During May 30–November 20, 2021, incident cases were defined using a positive nucleic acid amplification test (NAAT) result from the California COVID-19 Reporting System (CCRS) or a positive NAAT or antigen test result from the New York Electronic Clinical Laboratory Reporting System. In California, person-level hospitalization data from CCRS and supplementary hospitalization reports were used to identify COVID-19–associated hospitalizations. A lifetable method was used to calculate hazard rates (average daily cases during a 7-day interval or hospitalizations over a 14-day interval), hazard ratios, and 95% CIs for each cohort. Rates were age-adjusted to 2000 U.S. Census data using direct standardization.¶¶ Supplementary analyses stratified case rates by timing of previous diagnoses and primary series vaccine product. SAS (version 9.4; SAS Institute) and R (version 4.0.4; The R Foundation) were used to conduct all analyses. Institutional review boards (IRBs) in both states determined this surveillance activity to be necessary for public health work, and therefore, it did not require IRB review.

Approximately three quarters of adults from California (71.2%) and New York (72.2%) included in this analysis were vaccinated and did not have a previous COVID-19 diagnosis; however, 18.0% of California residents and 18.4% of New York residents were unvaccinated with no previous COVID-19 diagnosis (Table 1). In both states, 4.5% of persons were vaccinated and had a previous COVID-19 diagnosis; 6.3% in California and 4.9% in New York were unvaccinated with a previous diagnosis. Among 1,108,600 incident COVID-19 cases in these cohorts (752,781 in California and 355,819 in New York), the median intervals from vaccination or previous COVID-19 diagnosis to incident diagnosis were slightly shorter in California (138–150 days) than in New York (162–171 days).

Before the Delta variant became predominant in each state’s U.S. Department of Health and Human Services region (June 26 in Region 9 [California] and July 3 in Region 2 [New York]),*** the highest incidence was among unvaccinated persons without a previous COVID-19 diagnosis; during this time, case rates were relatively low among the three groups with either previous infection or vaccination and were lowest among vaccinated persons without a previous COVID-19 diagnosis (Supplementary Figure 1, https://stacks.cdc.gov/view/cdc/113253) (Supplementary Figure 2, https://stacks.cdc.gov/view/cdc/113253). During the week beginning May 30, 2021, compared with COVID-19 case rates among unvaccinated persons without a previous COVID-19 diagnosis, COVID-19 case rates were 19.9-fold (California) and 18.4-fold (New York) lower among vaccinated persons without a previous diagnosis; rates were 7.2-fold (California) and 9.9-fold (New York) lower among unvaccinated persons with a previous COVID-19 diagnosis and 9.6-fold (California) and 8.5-fold (New York) lower among vaccinated persons with a previous COVID-19 diagnosis (Table 2).

As the Delta variant prevalence increased to >95% (97% in Region 9 and 98% in Region 2 on August 1), rates increased more rapidly among the vaccinated group with no previous COVID-19 diagnosis than among both the vaccinated and unvaccinated groups with a previous COVID-19 diagnosis (Supplementary Figure 1, https://stacks.cdc.gov/view/cdc/113253) (Supplementary Figure 2, https://stacks.cdc.gov/view/cdc/113253). For example, during the week of October 3, compared with rates among unvaccinated persons without a previous COVID-19 diagnosis, rates among vaccinated persons without a previous diagnosis were 6.2-fold lower (95% CI = 6.0–6.4) in California and 4.5-fold lower (95% CI = 4.3–4.7) in New York (Table 2). Further, rates among unvaccinated persons with a previous COVID-19 diagnosis were 29-fold lower (95% CI = 25.0–33.1) than rates among unvaccinated persons without a previous COVID-19 diagnosis in California and 14.7-fold lower (95% CI = 12.6–16.9) in New York. Rates among vaccinated persons who had had COVID-19 were 32.5-fold lower (95% CI = 27.5–37.6) than rates among unvaccinated persons without a previous COVID-19 diagnosis in California and 19.8-fold lower (95% CI = 16.2–23.5) in New York. Rates among vaccinated persons without a previous COVID-19 diagnosis were consistently higher than rates among unvaccinated persons with a history of COVID-19 (3.1-fold higher [95% CI = 2.6–3.7] in California and 1.9-fold higher [95% CI = 1.5–2.3] in New York) and rates among vaccinated persons with a history of COVID-19 (3.6-fold higher [95% CI = 2.9–4.3] in California and 2.8-fold higher [95% CI = 2.1–3.4] in New York).

COVID-19 hospitalization rates in California were always highest among unvaccinated persons without a previous COVID-19 diagnosis (Table 2) (Figure). In the pre-Delta period during June 13–June 26, for example, compared with hospitalization rates among unvaccinated persons without a previous COVID-19 diagnosis, hospitalization rates were 27.7-fold lower (95% CI = 22.4–33.0) among vaccinated persons without a previous COVID-19 diagnosis, 6.0-fold lower (95% CI = 3.3–8.7) among unvaccinated persons with a previous COVID-19 diagnosis, and 7.1-fold lower (95% CI = 4.0–10.3) among vaccinated persons with a previous COVID-19 diagnosis. However, this pattern also shifted as the Delta variant became predominant. During October 3–16, compared with hospitalization rates among unvaccinated persons without a previous COVID-19 diagnosis, hospitalization rates were 19.8-fold lower (95% CI = 18.2–21.4) among vaccinated persons without a previous COVID-19 diagnosis, 55.3-fold lower (95% CI = 27.3–83.3) among unvaccinated persons with a previous COVID-19 diagnosis, and 57.5-fold lower (95% CI = 29.2–85.8) among vaccinated persons with a previous COVID-19 diagnosis.

Among the two cohorts with a previous COVID-19 diagnosis, no consistent incidence gradient by time since the previous diagnosis was observed (Supplementary Figure 3, https://stacks.cdc.gov/view/cdc/113253). When the vaccinated cohorts were stratified by the vaccine product received, among vaccinated persons without a previous COVID-19 diagnosis, the highest incidences were observed among persons receiving the Janssen (Johnson & Johnson), followed by Pfizer-BioNTech, then Moderna vaccines (Supplementary Figure 4, https://stacks.cdc.gov/view/cdc/113253). No pattern by product was observed among vaccinated persons with a previous COVID-19 diagnosis.

Discussion

This analysis integrated laboratory testing, hospitalization surveillance, and immunization registry data in two large states during May–November 2021, before widespread circulation of the SARS-CoV-2 Omicron variant and before most persons had received additional or booster COVID-19 vaccine doses to protect against waning immunity. Rate estimates from the analysis describe different experiences stratified by COVID-19 vaccination status and previous COVID-19 diagnosis and during times when different SARS-CoV-2 variants predominated. Case rates were initially lowest among vaccinated persons without a previous COVID-19 diagnosis; however, after emergence of the Delta variant and over the course of time, incidence increased sharply in this group, but only slightly among both vaccinated and unvaccinated persons with previously diagnosed COVID-19 (6). Across the entire study period, persons with vaccine- and infection-derived immunity had much lower rates of hospitalization compared with those in unvaccinated persons. These results suggest that vaccination protects against COVID-19 and related hospitalization and that surviving a previous infection protects against a reinfection. Importantly, infection-derived protection was greater after the highly transmissible Delta variant became predominant, coinciding with early declining of vaccine-induced immunity in many persons (5). Similar data accounting for booster doses and as new variants, including Omicron, circulate will need to be assessed.

The understanding and epidemiology of COVID-19 has shifted substantially over time with the emergence and circulation of new SARS-CoV-2 variants, introduction of vaccines, and changing immunity as a result. Similar to the early period of this study, two previous U.S. studies found more protection from vaccination than from previous infection during periods before Delta predominance (3,7). As was observed in the present study after July, recent international studies have also demonstrated increased protection in persons with previous infection, with or without vaccination, relative to vaccination alone†††, §§§ (4). This might be due to differential stimulation of the immune response by either exposure type.¶¶¶ Whereas French and Israeli population-based studies noted waning protection from previous infection, this was not apparent in the results from this or other large U.K. and U.S. studies**** (4,8). Further studies are needed to establish duration of protection from previous infection by variant type, severity, and symptomatology, including for the Omicron variant.

The findings in this report are subject to at least seven limitations. First, analyses were not stratified by time since vaccine receipt, but only by time since previous diagnosis, although earlier studies have examined waning of vaccine-induced immunity (Supplementary Figure 3, https://stacks.cdc.gov/view/cdc/113253) (2). Second, persons with undiagnosed infection are misclassified as having no previous COVID-19 diagnosis; however, this misclassification likely results in a conservative bias (i.e., the magnitude of difference in rates would be even larger if misclassified persons were not included among unvaccinated persons without a previous COVID-19 diagnosis). California seroprevalence data during this period indicate that the ratio of actual (presumptive) infections to diagnosed cases among adults was 2.6 (95% CI = 2.2–2.9).†††† Further, California only included NAAT results, whereas New York included both NAAT and antigen test results. However, antigen testing made up a smaller percentage of overall testing volume reported in California (7% of cases) compared with New York (25% of cases) during the study period. Neither state included self-tests, which are not easily reportable to public health. State-specific hazard ratios were generally comparable, although differences in rates among unvaccinated persons with a previous COVID-19 diagnosis were noteworthy. Third, potential exists for bias related to unmeasured confounding (e.g., behavioral or geographic differences in exposure risk) and uncertainty in the population size of the unvaccinated group without a previous COVID-19 diagnosis. Persons might be more or less likely to receive testing based on previous diagnosis or vaccination status; however, different trajectories between vaccinated persons with and without a previous COVID-19 diagnosis, and similar findings for cases and hospitalizations, suggest that these biases were minimal. Fourth, this analysis did not include information on the severity of initial infection and does not account for the full range of morbidity and mortality represented by the groups with previous infections. Fifth, this analysis did not ascertain receipt of additional or booster COVID-19 vaccine doses and was conducted before many persons were eligible or had received additional or booster vaccine doses, which have been shown to confer additional protection.§§§§ Sixth, some estimates lacked precision because of sample size limitations. Finally, this analysis was conducted before the emergence of the Omicron variant, for which vaccine or infection-derived immunity might be diminished.¶¶¶¶ This study offers a surveillance data framework to help evaluate both infections in vaccinated persons and reinfections as new variants continue to emerge.

Vaccination protected against COVID-19 and related hospitalization, and surviving a previous infection protected against a reinfection and related hospitalization during periods of predominantly Alpha and Delta variant transmission, before the emergence of Omicron; evidence suggests decreased protection from both vaccine- and infection-induced immunity against Omicron infections, although additional protection with widespread receipt of booster COVID-19 vaccine doses is expected. Initial infection among unvaccinated persons increases risk for serious illness, hospitalization, long-term sequelae, and death; by November 30, 2021, approximately 130,781 residents of California and New York had died from COVID-19. Thus, vaccination remains the safest and primary strategy to prevent SARS-CoV-2 infections, associated complications, and onward transmission. Primary COVID-19 vaccination, additional doses, and booster doses are recommended by CDC’s Advisory Committee on Immunization Practices to ensure that all eligible persons are up to date with COVID-19 vaccination, which provides the most robust protection against initial infection, severe illness, hospitalization, long-term sequelae, and death.***** Additional recommendations for vaccine doses might be warranted in the future as the virus and immunity levels change.

Acknowledgments

Dana Jaffe, California Department of Public Health; Rebecca Hoen, Meng Wu, New York State Department of Health; Citywide Immunization Registry Program, New York City Department of Health and Mental Hygiene.

Corresponding author: Tomás M. León, tomas.leon@cdph.ca.gov.


1California Department of Public Health; 2New York State Department of Health; 3University at Albany School of Public Health, SUNY, Rensselaer, New York; 4CDC.

All authors have completed and submitted the International Committee of Medical Journal Editors form for disclosure of potential conflicts of interest. No potential conflicts of interest were disclosed.

 https://covid.cdc.gov/covid-data-tracker/#cases_deathsper100klast7days

 Statewide immunization databases in California are the California Immunization Registry, Regional Immunization Data Exchange, and San Diego Immunization Registry; the laboratory system is the California COVID Reporting System (CCRS). In New York, immunization information systems include Citywide Immunization Registry and the New York State Immunization Information System; the laboratory system is the Electronic Clinical Laboratory Reporting System (ECLRS). California data were matched between the immunization and case registries using a probabilistic algorithm with exact match for zip code and date of birth and fuzzy match on first name and last name. New York data were matched to the ECLRS with the use of a deterministic algorithm based on first name, last name, and date of birth. In California, person-level hospitalization data from CCRS and supplementary hospitalization reports were used to identify COVID-19–associated hospitalizations.

§ For both classification into cohorts of persons with previous COVID-19 diagnoses and for measuring incident cases, laboratory-confirmed infection was defined as the receipt of a new positive SARS-CoV-2 nucleic acid amplification test (NAAT) or antigen test (both for New York and NAAT only for California) result, but not within 90 days of a previous positive result.

 Fully vaccinated with the primary vaccination series is defined as receipt of a second dose of an mRNA COVID-19 vaccine (Pfizer-BioNTech or Moderna) or 1 dose of the Janssen (Johnson & Johnson) vaccine ≥14 days before May 30, 2021.

** Because of the timing of full vaccination, the cohort definitions, and analysis timeframe, this cohort consisted nearly exclusively of persons who had previously received a laboratory-confirmed diagnosis of COVID-19 and later were fully vaccinated (California: 99.9%, New York: 99.7%), as opposed to the reverse order.

†† Whereas vaccinated cohorts were directly observed in the immunization information system databases, unvaccinated persons without a previous COVID-19 diagnosis were defined using U.S. Census population estimates minus the number of persons partially or fully vaccinated by December 11, 2021, and unvaccinated persons with a previous laboratory-confirmed infection before May 30, 2021. In California, the California Department of Finance population estimates were used for 2020, and the 2018 CDC National Center for Health Statistics Bridged Race file for U.S. Census population estimates were used in New York, consistent with other COVID-19 surveillance reporting.

§§ In California, a person-level match was performed to exclude deaths in each cohort before May 30, 2021. In New York, COVID-19 deaths were removed in aggregate from the starting number of unvaccinated persons with a previous COVID-19 diagnosis on May 30, 2021.

¶¶ https://www.cdc.gov/nchs/data/statnt/statnt20.pdfpdf icon

*** https://covid.cdc.gov/covid-data-tracker/#variant-proportions

††† https://www.medrxiv.org/content/10.1101/2021.09.12.21263461v1external icon

§§§ https://www.medrxiv.org/content/10.1101/2021.11.29.21267006v1external icon

¶¶¶ https://www.cdc.gov/coronavirus/2019-ncov/science/science-briefs/vaccine-induced-immunity.html#anchor_1635540449320

**** https://www.medrxiv.org/content/10.1101/2021.12.04.21267114v1external icon

†††† https://www.medrxiv.org/content/10.1101/2021.12.09.21267565v1external icon

§§§§ https://covid.cdc.gov/covid-data-tracker/#rates-by-vaccine-status

¶¶¶¶ https://www.medrxiv.org/content/10.1101/2021.12.30.21268565v1external iconhttps://www.medrxiv.org/content/10.1101/2022.01.07.22268919v1external icon

***** https://www.cdc.gov/vaccines/covid-19/clinical-considerations/covid-19-vaccines-us.html

Top

References

  1. Rosenberg ES, Holtgrave DR, Dorabawila V, et al. New COVID-19 cases and hospitalizations among adults, by vaccination status—New York, May 3–July 25, 2021. MMWR Morb Mortal Wkly Rep 2021;70:1306–11. https://doi.org/10.15585/mmwr.mm7037a7external icon PMID:34529645external icon
  2. Rosenberg ES, Dorabawila V, Easton D, et al. Covid-19 vaccine effectiveness in New York State. N Engl J Med 2021. Epub December 1, 2021. https://doi.org/10.1056/NEJMoa2116063external icon PMID:34942067external icon
  3. Cavanaugh AM, Spicer KB, Thoroughman D, Glick C, Winter K. Reduced risk of reinfection with SARS-CoV-2 after COVID-19 vaccination—Kentucky, May–June 2021. MMWR Morb Mortal Wkly Rep 2021;70:1081–3. https://doi.org/10.15585/mmwr.mm7032e1external icon PMID:34383732external icon
  4. Grant R, Charmet T, Schaeffer L, et al. Impact of SARS-CoV-2 Delta variant on incubation, transmission settings and vaccine effectiveness: Results from a nationwide case-control study in France. Lancet Reg Health Eur 2021. Epub November 26, 2021.  https://doi.org/10.1016/j.lanepe.2021.100278external icon
  5. Self WH, Tenforde MW, Rhoads JP, et al.; IVY Network. Comparative effectiveness of Moderna, Pfizer-BioNTech, and Janssen (Johnson & Johnson) vaccines in preventing COVID-19 hospitalizations among adults without immunocompromising conditions—United States. MMWR Morb Mortal Wkly Rep 2021;70:1337–43. https://doi.org/10.15585/mmwr.mm7038e1external icon PMID:34555004external icon
  6. Lin D-Y, Gu Y, Wheeler B, et al. Effectiveness of Covid-19 vaccines in the United States over 9 months: surveillance data from the state of North Carolina. [Preprint posted online October 26, 2021.] https://www.medrxiv.org/content/10.1101/2021.10.25.21265304v1external icon
  7. Bozio CH, Grannis SJ, Naleway AL, et al. Laboratory-confirmed COVID-19 among adults hospitalized with COVID-19–like illness with infection-induced or mRNA vaccine-induced SARS-CoV-2 immunity—nine states, January–September 2021. MMWR Morb Mortal Wkly Rep 2021;70:1539–44. https://doi.org/10.15585/mmwr.mm7044e1external icon PMID:34735425external icon
  8. Kim P, Gordon SM, Sheehan MM, Rothberg MB. Duration of SARS-CoV-2 natural immunity and protection against the Delta variant: a retrospective cohort study. Clin Infect Dis 2021. Epub December 3, 2021. https://doi.org/10.1093/cid/ciab999external icon PMID:34864907external icon

4,811 recovered Israeli COVID patients got reinfected — TV

Authors: FROM THE LIVEBLOG OF THURSDAY, AUGUST 26, 2021 7:56 pm  

Health Ministry data cited by Channel 13 suggests the Delta variant may be more effective at causing COVID reinfection among recovered patients than earlier strains of the coronavirus.

According to the data, 4,811 Israelis have been reinfected with coronavirus, accounting for 0.47 percent of the total recoveries. (The data provided refers to over 900,000 recovered Israelis, though the figure has since surpassed a million).

However, just 0.08% of the reinfection cases were recorded in 2020, while the number climbed to 0.71% in 2021 when the Delta variant became the dominant strain in Israel. In the past month, 2,702 recovered patients contracted the coronavirus again, or some 1.8%, the report says. It is unclear to what extent the Delta variant is more effective and to what extent the reinfections are the result of waning antibodies.

The majority of reinfections are among the young, according to the report.