Omicron is considered a milder coronavirus, but scientists aren’t so sure

Authors: Melissa Healy August 13, 2022 la times

For more than two years, Cathy Baron and Sara Alicia Costa managed to duck the coronavirus. But despite their being fully vaccinated and boosted, the Omicron variant finally caught them.

Baron is an actress and dance instructor who lives in Santa Monica. Costa is an architect in Austin, Texas. Both are 40 and healthy. But the two friends saw two very different sides of the variant they expected to be gentler on its victims than earlier strains.

For Costa, the Omicron variant lived up to its reputation for mildness, causing headaches and “something like a crummy cold” for a couple of days. She was visiting Baron and surfing in Santa Monica a week after testing positive.

Baron’s illness was deeply chastening. She was flattened for several days with a high fever and debilitating muscle aches and was too exhausted to teach her pole dancing class for three weeks. Two months later, she’s still coping with fatigue, brain fog and episodic coughing fits. She hopes never to repeat the experience.

Baron and Costa are what scientists would dismiss as an “n of 2.” If their experience were a study, the sample size would be far too small to draw any conclusions, especially one as important as whether the Omicron variant really is less virulent than the SARS-CoV-2 variants that came before it.

And yet, their contrasting experiences are as telling as many of the research studies conducted to date that have tried to determine how dangerous Omicron really is.

“It’s an excellent question,” said Dr. Stanley Perlman, a University of Iowa virologist and a leading expert on coronaviruses. Many researchers think they know the answer, and “I think it’s true” that the Omicron variant is causing milder illnesses, he said. But the true picture is “not clear,” he cautioned.

Omicron arrived in the United States at a time when 60% of Americans had the protection of COVID-19 vaccines and roughly a third of Americans (including some who’d been vaccinated) had a past infection. Not only was there a high level of population immunity, those who did become ill had access to treatments that weren’t available to people sickened by the initial strain from Wuhan, China, or the Alpha and Delta variants that followed.

Perhaps these are the reasons why those infected with Omicron have tended to experience milder illnesses.

“It’s widely said that Omicron is inherently less pathogenic, but there is no real evidence for that,” said Dr. Christopher Chiu, a COVID-19 researcher at Imperial College London.

“Comparisons with Delta are like apples and oranges,” he said. “Delta was circulating at a time when many were still not vaccinated or previously infected. In contrast, Omicron is largely causing breakthrough infections in people who already have partial protection from immunity conferred by vaccines or infection.”

Since its earliest appearance in November, researchers have seen that compared with previous variants, Omicron was less likely to send infected people to the hospital or to their graves.

First in South Africa and later in communities across America, the new variant bucked expectations spawned by earlier surges. In the two to three weeks after Omicron cases spiked, hospitalizations and deaths rose as well — but more slowly, and they’d topped out at lower levels.

Still, as Americans have learned from hard experience, the Omicron variant is a highly capable killer. Just over 200,000 of the country’s COVID-19 deaths are likely attributable to some version of the Omicron variant, which arrived here around Thanksgiving and became dominant in January.

And don’t forget, Perlman added: It’s still killing some 400 people a day in the United States.

How much of Omicron’s supposed mildness should be credited to the protective effect of vaccines is not really known.

During June, the Centers for Disease Control and Prevention concluded that COVID-associated hospitalizations among unvaccinated adults were 4.6 times higher than they were among vaccinated people. But the picture is muddier than such data would suggest.

Americans’ immune profiles run the gamut, making it hard to slot people into neat categories and compare how they fared when infected by different variants. Those who’ve been vaccinated are experiencing various degrees of waning immunity, even if they’ve been boosted. The same goes for people who’ve recovered from infections. The readiness of their immune systems depends on how long ago they had the infection, what variant infected them, their vaccination status, and factors like age and the medications they take.

With so many variables to consider, it’s hard for researchers to draw a clean comparison between Omicron and its predecessors. But they’ve tried.

In one study published in Nature, scientists showed that Omicron was drawn to a wide range of human tissues. When observed in petri dishes, the variant established itself in cells that mimicked the upper airways of the respiratory system, though with less gusto than the Delta variant. In addition, Omicron was far less adept at infecting lower airway cells, including lung tissue, than either Delta or the original SARS-CoV-2 strain that left Wuhan.

And in studies that infected animals such as hamsters and genetically engineered mice, the Omicron variant caused less weight loss (a proxy of severe disease) and touched off less inflammation in the lungs than either Delta or the original strain.

Adding to the uncertainty is the fact that coronavirus testing was undergoing sweeping changes just as the Omicron variant took hold. As at-home testing ramped up and fewer new infections were reported to public health agencies, the relationship between cases on the one hand and hospitalizations and deaths on the other — a previously dependable measure of a variant’s ability to sicken — became less reliable.

The Omicron variant’s astonishing infectiousness and propensity to spin off new subvariants complicate the picture even more. In a recent meeting convened by the Food and Drug Administration, even experts from the agency shrugged when asked to compare the subvariants.

Collectively, those Omicron subvariants muscled Delta aside so quickly that doctors and researchers didn’t have time to collect groups of similar patients, genetically sequence the viruses that infected them, and compare how their illnesses proceeded.

That’s the kind of study that might shed light on the divergent experiences of Cathy Baron and Sara Alicia Costa. They’re a seemingly well-matched pair of healthy 40-year-old women, yet Omicron attacked one of them like a lion and treated the other like a lamb. With the experiences of hundreds or thousands of people thrown in, such research might reveal factors that nudge an Omicron infection in one direction or the other.

There is a more direct way to learn how Omicron compares to earlier variants in its ability to sicken and kill. Researchers could deliberately infect volunteers with different versions of the coronavirus and track their physiological responses to infection over the course of an illness.

Chiu and his colleagues at Imperial College London have just such an undertaking in mind. They are planning “human challenge” studies involving the Delta and Omicron variants to mirror one already conducted with the original version of the virus.

The resulting data could yield a clearer picture of exactly how Omicron behaves in healthy humans, and how a prior infection or different levels of vaccination affect an individual’s illness.

Chiu said a new study would seek to enroll people who gained immunity through vaccination, a past infection, or a combination of both. That would give them more insight into whether so-called hybrid immunity is an important bulwark against becoming sick in the Omicron era.

If research confirms that the Omicron variant is indeed milder than its predecessors, and that getting it confers some protection from future illness, some may conclude it’s time to let the virus spread.

Baron would take some convincing of that.

“When people say, ‘let’s just let it rip’ and allow ourselves to get infected over and over again — that’s scary to me,” she said. “I don’t want to just let it rip. I don’t want to get it again.”

Duration of Shedding of Culturable Virus in SARS-CoV-2 Omicron (BA.1) Infection

Authors: Julie Boucau, Ph.D. Caitlin Marino, B.S. Ragon Institute, Cambridge, MA

James Regan, B.S. Brigham and Women’s Hospital, Boston, MA Rockib Uddin, B.S.
Massachusetts General Hospital, Boston, MA Manish C. Choudhary, Ph.D.
James P. Flynn, B.S. Brigham and Women’s Hospital, Boston, MA Geoffrey Chen, B.A.
Ashley M. Stuckwisch, B.S. Josh Mathews, A.B. May Y. Liew, B.A. Arshdeep Singh, B.S.
Taryn Lipiner, M.P.H. Massachusetts General Hospital, Boston, MA Autumn Kittilson, B.S. Meghan Melberg, B.S. Yijia Li, M.D. Brigham and Women’s Hospital, Boston, MARebecca F. Gilbert, B.A. Zahra Reynolds, M.P.H. Surabhi L. Iyer, B.A. Grace C.Chamberlin, B.A. Tammy D. Vyas, B.S. Marcia B. Goldberg, M.D.Jatin M. Vyas, M.D., Ph.D.Massachusetts General Hospital, Boston, MAJonathan Z. Li, M.D.Brigham and Women’s Hospital, Boston, MA Jacob E. Lemieux, M.D., D.Phil. Mark J. Siedner, M.D., M.P.H.Amy K. Barczak, M.D.Massachusetts General Hospital, Boston, MA

July 21, 2022 N Engl J Med 2022; 387:275-277 DOI: 10.1056/NEJMc2202092

The B.1.1.529 (omicron) variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has a shorter incubation period and a higher transmission rate than previous variants.1,2 Recently, the Centers for Disease Control and Prevention recommended shortening the strict isolation period for infected persons in non–health care settings from 10 days to 5 days after symptom onset or after the initial positive test, followed by 5 days of masking.3 However, the viral decay kinetics of the omicron variant and the duration of shedding of culturable virus have not been well characterized.

We used longitudinal sampling of nasal swabs for determination of viral load, sequencing, and viral culture in outpatients with newly diagnosed coronavirus disease 2019 (Covid-19).4 From July 2021 through January 2022, we enrolled 66 participants, including 32 with samples that were sequenced and identified as the B.1.617.2 (delta) variant and 34 with samples that were sequenced and identified as the omicron subvariant BA.1, inclusive of sublineages. Participants who received Covid-19–specific therapies were excluded; all but 1 participant had symptomatic infection. This study was approved by the institutional review board and the institutional biosafety committee at Mass General Brigham, and informed consent was obtained from all the participants. Figure 1.Viral Decay and Time to Negative Viral Culture.

The characteristics of the participants were similar in the two variant groups except that more participants with omicron infection had received a booster vaccine than had those with delta infection (35% vs. 3%) (Tables S1 and S2 in the Supplementary Appendix, available with the full text of this letter at NEJM.org). In an analysis in which a Cox proportional-hazards model that adjusted for age, sex, and vaccination status was used, the number of days from an initial positive polymerase-chain-reaction (PCR) assay to a negative PCR assay (adjusted hazard ratio, 0.61; 95% confidence interval [CI], 0.33 to 1.15) and the number of days from an initial positive PCR assay to culture conversion (adjusted hazard ratio, 0.77; 95% CI, 0.44 to 1.37) were similar in the two variant groups (Figure 1A through 1C and S1 through S3, and Tables S3 through S5). The median time from the initial positive PCR assay to culture conversion was 4 days (interquartile range, 3 to 5) in the delta group and 5 days (interquartile range, 3 to 9) in the omicron group; the median time from symptom onset or the initial positive PCR assay, whichever was earlier, to culture conversion was 6 days (interquartile range, 4 to 7) and 8 days (interquartile range, 5 to 10), respectively. There were no appreciable between-group differences in the time to PCR conversion or culture conversion according to vaccination status, although the sample size was quite small, which led to imprecision in the estimates (Figure 1D and 1E).

In this longitudinal cohort of participants, most of whom had symptomatic, nonsevere Covid-19 infection, the viral decay kinetics were similar with omicron infection and delta infection. Although vaccination has been shown to reduce the incidence of infection and the severity of disease, we did not find large differences in the median duration of viral shedding among participants who were unvaccinated, those who were vaccinated but not boosted, and those who were vaccinated and boosted.

Our results should be interpreted within the context of a small sample size, which limits precision, and the possibility of residual confounding in comparisons according to variant, vaccination status, and the time period of infection. Although culture positivity has been proposed as a possible proxy for infectiousness,5 additional studies are needed to correlate viral-culture positivity with confirmed transmission in order to inform isolation periods. Our data suggest that some persons who are infected with the omicron and delta SARS-CoV-2 variants shed culturable virus more than 5 days after symptom onset or an initial positive test.

Natural Immunity From Omicron Strong Against Virus Subvariants: Study

Authors: Zachary Stieber via The Epoch Times, UL 18, 2022

The protection afforded by surviving COVID-19 was strong against the latest virus subvariants, including the one currently dominant in the United States, scientists in Qatar found.

People who were infected with Omicron, a variant of SARS-CoV-2, had 76.1 percent protection against symptomatic reinfection from BA.4 and BA.5 and 80 percent shielding from any reinfection, regardless of symptoms, according to the preprint study.

SARS-CoV-2, also known as the CCP (Chinese Communist Party) virus, causes COVID-19.

Omicron became the dominant virus strain in many countries in late 2021. Since then, a number of subvariants have taken hold. BA.5 is the strain currently dominant in the United States.

While protection from an Omicron infection provided robust shielding against reinfection, those who contracted a pre-Omicron strain had little protection, according to the Qatari scientists, who were led by Dr. Laith Abu-Raddad with Weill Cornell Medicine-Qatar.

Pre-Omicron infection provided just 15.1 percent effectiveness against symptomatic BA.4 and BA.5 reinfection and just 28 percent infection against any reinfection.

The scientists analyzed data from national COVID-19 databases.

Infections before Omicron were those that occurred before Dec. 19, 2021, when the variant wave started in Qatar.

Protection ‘Strong’

“Protection of a previous infection against BA.4/BA.5 reinfection was modest when the previous infection involved a pre-Omicron variant, but strong when the previous infection involved the Omicron BA.1 or BA.2 subvariant,” the scientists wrote.

Natural immunity has long been found to be superior to the protection from COVID-19 vaccines, and the new study is no exception. Vaccines provide little protection against Omicron infection and perform worse against infection and severe illness from the BA.4 and BA. 5 subvariants, studies have shown.

Natural immunity also waned against BA.4 and BA.5, highlighting how the subvariants are better at evading protection, the Qatari researchers found.

The group has been studying natural immunity for years and recently discovered that the protection from prior infection against severe disease showed no signs of waning, regardless of what strain infected the person.

Among the listed limitations for the new study was the young population of Qatar, where just 9 percent of residents are 50 years of age or older. That means the findings “may not be generalizable to other countries where elderly citizens constitute a larger proportion of the total population,” researchers wrote.

Some experts, including Abu-Raddad and U.S. Centers for Disease Control and Prevention Director Dr. Rochelle Walensky, continue recommending vaccination for people with natural immunity, pointing to studies that indicate one or more doses increase protection, but others say vaccination isn’t needed for people who survive COVID-19, since some research suggests the elevated protection is minimal and that the naturally immune are at higher risk of vaccine side effects.

VIRAL THREAT 

New Covid variant dubbed ‘Centaurus’ already ‘detected in 10 countries including UK and US’

Authors: Vanessa Chalmers U.S, Sun Jul 19 2022

BA.2.75, nicknamed Centaurus, was first detected and is spreading rapidly in India.

It is a relative of Omicon, the original strains of which were shown to be more mild Covid illness (BA.1 and BA.2).

Health chiefs, however, do not know how new versions of Omicron (BA.2.75, BA.4 and BA.5) compare.

But it is feared that Centaurus is even more infectious than Omicron strains that have come before it.

The UK has seen 18 cases to date, and is among roughly 10 countries where Centaurus has been detected.

Professor Susan Hopkins, Chief Medical Advisor at UKHSA said: “We are aware of a small number of cases of the emergent variant Omicron BA.2.75 in the UK.

“At this point, it is too early to draw conclusions about the relative transmissibility of this variant, or the illness it may cause, compared to the currently-dominant variants.

“UKHSA is monitoring the situation closely, as we do all data relating to SARS-CoV-2 variants in the UK and around the globe through our world-leading genomic surveillance systems.”

BA.2.75 appears to be spreading faster than other variants in India, Lipi Thukral, a scientist at the Council of Scientific and Industrial Research-Institute of Genomics and Integrative Biology in New Delhi, told MedicalXpress

New coronavirus subvariants escape antibodies from vaccination and prior Omicron infection, studies suggest

Authors: Jacqueline Howard, CNN June 23, 2022

Omicron subvariants BA.4 and BA.5 appear to escape antibody responses among both people who had previous Covid-19 infection and those who have been fully vaccinated and boosted, according to new data from researchers at Beth Israel Deaconess Medical Center, of Harvard Medical School.

However, Covid-19 vaccination is still expected to provide substantial protection against severe disease, and vaccine makers are working on updated shots that might elicit a stronger immune response against the variants.

The levels of neutralizing antibodies that a previous infection or vaccinations elicit are several times lower against the BA.4 and BA.5 subvariants compared with the original coronavirus, according to the new research published in the New England Journal of Medicine on Wednesday.

“We observed 3-fold reductions of neutralizing antibody titers induced by vaccination and infection against BA4 and BA5 compared with BA1 and BA2, which are already substantially lower than the original COVID-19 variants,” Dr. Dan Barouch, an author of the paper and director of the Center for Virology and Vaccine Research at Beth Israel Deaconess Medical Center in Boston, wrote in an email to CNN.

“Our data suggest that these new Omicron subvariants will likely be able to lead to surges of infections in populations with high levels of vaccine immunity as well as natural BA1 and BA2 immunity,” Barouch wrote. “However, it is likely that vaccine immunity will still provide substantial protection against severe disease with BA4 and BA5.”

The newly published findings echo separate research by scientists at Columbia University.

They recently found that the BA.4 and BA.5 viruses were more likely to escape antibodies from the blood of fully vaccinated and boosted adults compared with other Omicron subvariants, raising the risk of vaccine-breakthrough Covid-19 infections.

The authors of that separate study say their results point to a higher risk for reinfection, even in people who have some prior immunity against the virus. The US Centers for Disease Control and Prevention estimates 94.7% of the US population ages 16 and older have antibodies against the coronavirus that causes Covid-19 through vaccination, infection, or both.

BA.4 and BA.5 caused an estimated 35% of new Covid-19 infections in the United States last week, up from 29% the week before, according to data shared by the US Centers for Disease Control and Prevention on Tuesday.

BA.4 and BA.5 are the fastest spreading variants reported to date, and they are expected to dominate Covid-19 transmission in the United States, United Kingdom and the rest of Europe within the next few weeks, according to the European Centre for Disease Prevention and Control.

‘COVID-19 still has the capacity to mutate further’

In the New England Journal of Medicine paper, among 27 research participants who had been vaccinated and boosted with the Pfizer/BioNTech coronavirus vaccine, the researchers found that two weeks after the booster dose, levels of neutralizing antibodies against Omicron subvariants were much lower than the response against the original coronavirus.

The neutralizing antibody levels were lower by a factor of 6.4 against BA.1; by a factor of 7 against BA.2; by a factor of 14.1 against BA.2.12.1 and by a factor of 21 against BA.4 or BA.5, the researchers described.

Among 27 participants who had previously been infected with the BA.1 or BA.2 subvariants a median of 29 days earlier, the researchers found similar results.

In those with previous infection – most of whom also had been vaccinated – the researchers described neutralizing antibody levels that were lower by a factor of 6.4 against BA.1; by a factor of 5.8 against BA.2; by a factor of 9.6 against BA.2.12.1 and by a factor of 18.7 against BA.4 or BA.5.

More research is needed to determine what exactly the neutralizing antibody levels mean for vaccine effectiveness and whether similar findings would emerge among a larger group of participants.

“Our data suggest that COVID-19 still has the capacity to mutate further, resulting in increased transmissibility and increased antibody escape,” Barouch wrote in the email. “As pandemic restrictions are lifted, it is important that we remain vigilant and keep studying new variants and subvariants as they emerge.”

A separate study, published in the journal Nature last week, found that Omicron may evolve mutations to evade the immunity elicited by having a previous BA.1 infection, which suggests that vaccine boosters based on BA.1 may not achieve broad-spectrum protection against new Omicron subvariants like BA.4 and BA.5.

As for what all this means in the real world, Dr. Wesley Long, an experimental pathologist at Houston Methodist Hospital, told CNN that people should be aware that they could get sick again, even if they’ve had Covid-19 before.

“I think I’m a little bit worried about people who’ve had it maybe recently having a false sense of security with BA.4 and BA.5 on the increase, because we have seen some cases of reinfection and I have seen some cases of reinfection with people who had a BA.2 variant in the last few months,” he said.

Some vaccine makers have been developing variant-specific vaccines to improve the antibody responses against coronavirus variants and subvariants of concern.

“Reinfections are going to be pretty inevitable until we have vaccines or widespread mandates that are going to prevent cases rising again. But the good news is that we are in, I think, a much better spot than we were without the vaccines,” said Pavitra Roychoudhury, an acting instructor at the University of Washington’s Department of Laboratory Medicine and Pathology, who was not involved in the New England Journal of Medicine paper.

“There’s so much of this virus out there that it seems inevitable,” she said about Covid-19 infections. “Hopefully the protections that we have in place are going to lead to mostly mild infection.”

Efforts underway to update Covid-19 vaccines

Moderna’s bivalent Covid-19 vaccine booster, named mRNA-1273.214, elicited a “potent” immune responses against the Omicron subvariants BA.4 and BA.5, the company said Wednesday.

This bivalent booster vaccine candidate contains components of both Moderna’s original Covid-19 vaccine and a vaccine that targets the Omicron variant. The company said it is working to complete regulatory submissions in the coming weeks requesting to update the composition of its booster vaccine to be mRNA-1273.214.

“In the face of SARS-CoV-2’s continued evolution, we are very encouraged that mRNA-1273.214, our lead booster candidate for the fall, has shown high neutralizing titers against the BA.4 and BA.5 subvariants, which represent an emergent threat to global public health,” Stéphane Bancel, chief executive officer of Moderna, said in Wednesday’s announcement. SARS-CoV-2 is the coronavirus that causes Covid-19.

“We will submit these data to regulators urgently and are preparing to supply our next generation bivalent booster starting in August, ahead of a potential rise in SARS-CoV-2 infections due to Omicron subvariants in the early fall,” Bancel said.

The US Food and Drug Administration’s Vaccines and Related Biological Products Advisory Committee is meeting next week to discuss the composition of Covid-19 vaccines that could be used as boosters this fall.

The data that Moderna released Wednesday, which has not been published in a peer-reviewed journal, showed that one month after a 50-microgram dose of the mRNA-1273.214 vaccine was administered in people who had been vaccinated and boosted, the vaccine elicited “potent” neutralizing antibody responses against BA.4 and BA.5, boosting levels 5.4-fold in all participants regardless of whether they had a prior Covid-19 infection and by 6.3-fold in the subset of those with no history of prior infection. These levels of neutralizing antibodies were about 3-fold lower than previously reported neutralizing levels against BA.1, Moderna said.

These findings add to the data that Moderna previously released earlier this month, showing that the 50-microgram dose of the bivalent booster generated a stronger antibody response against Omicron than the original Moderna vaccine.

GET CNN HEALTH’S WEEKLY NEWSLETTER

Sign up here to get The Results Are In with Dr. Sanjay Gupta every Tuesday from the CNN Health team.

Moderna’s data suggest that “the bivalent booster might confer greater protection against the BA.4 and BA.5 omicron strains than readministering the original vaccine to increase protection across the population. Although the information is based on antibody levels, the companies comment that similar levels of antibody protected against clinical illness caused by other strains is the first suggestion of an emerging ‘immune correlate’ of protection, although it is hoped that this ongoing study is also assessing rates of clinical illness as well as antibody responses,” Penny Ward, an independent pharmaceutical physician and visiting professor in pharmaceutical medicine at King’s College London, said in a statement released by the UK-based Science Media Centre on Wednesday. She was not involved in Moderna’s work.

“It has been reported previously that the bivalent vaccine is well tolerated with temporary ‘reactogenic’ effects similar to those following the univalent booster injection so we can anticipate that this new mixed vaccine should be well tolerated,” Ward said in part. “As we head towards the autumn with omicron variants dominating the covid infection landscape, it certainly makes sense to consider use of this new bivalent vaccine, if available.”

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.

This May Be the COVID Variant Scientists Are Dreading

Authors: David Axe June 20, 2022 TDB

COVID-19 cases are increasing again in the United Kingdom, potentially signaling a future surge in infections in the United States and other countries.

A pair of new subvariants of the dominant Omicron variant—BA.4 and BA.5—appear to be driving the uptick in cases in the U.K. Worryingly, these subvariants seem to partially dodge antibodies from past infection or vaccination, making them more transmissible than other forms of the SARS-CoV-2 virus.

There are also some suggestions that the new subvariants have evolved to target the lungs—unlike Omicron, which usually resulted in a less dangerous infection of the upper respiratory tract.

But there’s good news amid the bad. While cases are going up in the U.K., hospitalizations and deaths are increasing more slowly or even declining so far. “This could mean higher transmissible variants, BA.4 or 5, are in play, [and] these variants are much less severe,” Edwin Michael, an epidemiologist at the Center for Global Health Infectious Disease Research at the University of South Florida, told The Daily Beast.

The trends could change, of course, but the decrease in deaths is an encouraging sign that, 31 months into the pandemic, all that immunity we’ve built up–at the cost of half a billion infections and tens of billions of dollars’ worth of vaccines—is still mostly holding.

As far as COVID goes, things were really looking up in the U.K. until recently. COVID cases steadily declined from their recent peak of 89,000 daily new infections in mid-March. Deaths from the March wave peaked a month later at around 330 a day.

The Massive Screwup That Could Let COVID Bypass Our Vaccines

By early June cases and deaths were near their pandemic lows. Then came BA.4 and BA.5. The grandchildren of the basic Omicron variant that first appeared in the fall of 2021, BA.4 and BA.5 both feature a trio of major mutations to their spike protein, the part of the virus that helps it to grab onto and infect our cells.

Eric Bortz, a University of Alaska-Anchorage virologist and public-health expert, described BA.4 and BA.5 as “immunologically distinct sublineages.” In other words, they interact with our antibodies in surprising new ways.

The European Center for Disease Prevention and Control—the European Union’s answer to the U.S. Centers for Disease Control and Prevention—labeled BA.4 and BA.5 “variants of concerns” back in mid-May. Two weeks later the two new subvariants began the gradual process of overtaking older forms of Omicron in the U.K. That’s when cases began increasing again.

It doesn’t help that the U.K. like most countries—China is a big exception—has lifted almost all restrictions on schools, businesses, crowds and travel. Those restrictions helped to keep down cases, but were broadly unpopular and came at a high economic cost.

“There’s a disconnect between the actuality of how infections are happening… and how people are deciding not to take very many precautions,” John Swartzberg, a professor emeritus of infectious diseases and vaccinology at the University of California-Berkeley’s School of Public Health, told The Daily Beast. He described it as “COVID fatigue… 100 percent of the world’s population must have it by now.”

The combination of a fully reopened economy and new COVID subvariants had an immediate effect. The U.K. Health Security Agency registered 62,228 new infections in the week ending June 10, a 70 percent uptick over the previous week. COVID hospitalizations grew more slowly over the same period, spiking 30 percent to 4,421.

COVID fatalities actually dropped, however—sliding 10 percent to 283. Deaths tend to lag infections by several weeks, of course, so it should come as no surprise if the death rate flattens or bumps up later this month or early next month.

But it’s possible it won’t. Yes, BA.4 and BA.5 are more transmissible, owing to that mutated spike protein. But that doesn’t mean they’re going to kill a lot of people. Despite their unusual qualities, it could be that BA.4 and BA.5 aren’t actually more dangerous than previous subvariants.

Bortz sketched out one possibility, that BA.4 and BA.5 are “immune-evasive enough to infect, but generally not evasive enough to counteract acquired immunity from vaccines and/or prior infection.”

Of course, immunity varies from community to community, country to country. The U.K.’s 67 million people have, for their part, built up pretty serious immunity over the past two-and-a-half years.

Tens of millions of U.K. residents have natural antibodies from past infection. 87 percent of the population is fully vaccinated. 68 percent is boosted. All those antibodies might not prevent breakthrough infections, but they do tend to prevent serious breakthrough infections.

How bad the current surge in cases gets depends to a great extent on the durability of those antibodies. Immunity, whether from past infection or vaccines, tends to wane over time. But how fast it wanes, and to what effect, is unpredictable.

It’s possible widespread immunity holds and the swelling BA.4 and BA.5 wave in the U.K. crests in a few weeks without making a whole lot more people sick—or killing them. That’s the best-case scenario given the lack of political will, and public support, for a new round of restrictions. “If higher cases would not lead to significant disease or deaths, then we may be able to live with this virus,” Michael said.

The worst-case scenario is that BA.4 and BA.5 prove more capable of evading our antibodies than experts currently anticipate. Keep an eye on the hospitalization stats. If COVID hospitalizations start increasing in proportion to the growth in cases, it’s a sign the new sublineages are dodging our hard-won immunity.

In that case, a big spike in deaths is sure to follow.

That could be a big red flag for the Americas. COVID variants tend to travel from east to west, globally. New variants and subvariants tend to appear in the United States a few weeks after becoming dominant in the U.K. At present, BA.4 and BA.5 account for just a fifth of new cases in the U.S. Expect that proportion to increase.

The problem for Americans is that they’re much less protected than Britons. Yes, Americans have a lot of antibodies from past infection, but they’re also a lot less likely to be vaccinated—and even less likely to be boosted. Just 67 percent of Americans are fully vaxxed. A little over a third of the U.S. population has gotten a booster.

So if BA.4 and BA.5 end up causing a surge in deaths in the U.K., they’re likely to inflict an even greater death toll on the other side of the Atlantic Ocean. “We’re sort of in this zone now, betwixt and between,” Swartzberg said. “It’s unclear which way things are going to go.”

Omicron sub-variants BA.4 and BA.5 account for up to 13% of COVID variants in U.S. – CDC

Authors: Mrinalika Roy Reuters

The BA.4 and BA.5 sub-variants of Omicron are estimated to make up nearly 5% and 8% of the coronavirus variants in the United States as of June 4, the U.S. Centers for Disease Control and Prevention (CDC) said on Tuesday.

The two sublineages, which were added to the World Health Organization’s monitoring list in March and designated as variants of concern by the European Centre for Disease Prevention and Control (ECDC), were present in all U.S. regions.

Last month, South African scientists found that the sublineages of the Omicron coronavirus variant can dodge antibodies from earlier infection well enough to trigger a new wave.

BA.4 made up 5.4% of the variants in the country for the week ending June 4, according to CDC estimates, while BA.5 made up 7.6% of the variants during the same time.

The seven-day moving average of U.S. COVID-19 cases stood at 98,010 as of June 4.

Overlapping, highly contagious COVID subvariants are spreading fast in Florida

Authors: David Schutz, Cindy Krischer Goodman June 4, 2022 Sun Sentinel

Overlapping waves of omicron are sweeping through the state, leading more people to get infected with COVID.

The more transmissible BA.2.12.1 omicron subvariant became officially dominant in the U.S. last week, yet it already is being pushed out nationally by newcomers BA.4 and BA.5, both of which have arrived in Florida.

While BA.2.12.1 has gained an advantage by being more contagious than the omicron subvariant BA.2 before it, the newcomers (4 and 5) are particularly good at evading antibodies and infecting those who are vaccinated or previously infected.

Some epidemiologists are describing what’s happening as the “battle of omicron.”

Helix, a private lab that identifies COVID strains circulating in states, found BA.4 and BA.5 crept into Florida in May, and represent about 5% of samples. The majority of cases in Florida — about 58% — are still BA.2.12.1.

The omicron subvariant BA.4 was first identified in January in cases sequenced in South Africa, and BA.5 surfaced a month later. The omicron strain, BA.2.12.1, accounted for nearly all of South Africa’s daily cases at the end of February. By the end of April, however, BA.4 and BA.5 were found in 90% of all positive test samples analyzed in that nation, exemplifying the infectiousness of the newcomers.

Health officials say evidence seems to point to increasingly rapid, overlapping waves of new variants, which likely means more infections in Florida in the summer months ahead.

“My theory is we may see more variants, and they may be more contagious, but they will continue to get less problematic with fewer harmful outcomes,” said Dr. Mona Amin with Pediatric Associates in Fort Lauderdale.

In Florida, much like other states, COVID reporting has become spotty with many learning of the diagnosis through at-home tests. So far, wastewater has proven useful in learning the prevalence of the virus.

An analysis of wastewater in South Florida counties by Biobot Analytics, shows COVID cases are rising to levels last seen during the winter omicron wave in early 2022. Delta no longer is a factor in the state, Biobot’s analysis shows. The samples taken in Miami-Dade and Palm Beach counties show omicron and its subvariants are circulating at increasingly high levels.

With a seven-day daily average of more than 10,200 cases on Friday, Florida is a state classified by the Centers for Disease Control and Prevention as having a “high level” of transmission. Broward and Miami-Dade counties are reporting a test positivity rate of more than 20%. Palm Beach County’s positivity rate is 18.9%. Health officials consider transmission levels under control when the rate is less than 5%.

Jason Salemi, an epidemiologist at the University of South Florida, points out, “We might actually (finally) be seeing some improvement in the Northeast, but in Florida — 3 in 4 people live in a high-risk county, based on the hospitalization-based measure.”

On Friday, 2,834 people were in Florida hospitals with COVID, representing nearly 5% of all beds, according to U.S. Health and Human Services data. That’s a significant increase from about 1,000 COVID patients in early April, but nowhere near the more than 17,000 people hospitalized during the delta wave in August 2021.

New Omicron BA.4 and BA.5 Sublineages May Evade Vaccines, Natural Immunity. What Experts Say

Authors: Mint Newsletters April 29, 2022

  • The BA.4 and BA.5 sublineages appear to be more infectious than the earlier BA.2 lineage
  • The sub-lineages have been detected in seven of South Africa’s nine provinces and 20 countries worldwide

New omicron sublineages, discovered by South African scientists this month, are likely able to evade vaccines and natural immunity from prior infections, the head of gene sequencing units that produced a study on the strains said, according to Bloomberg report.

It is important to note that the BA.4 and BA.5 sublineages appear to be more infectious than the earlier BA.2 lineage, which itself was more infectious than the original omicron variant, Tulio de Oliveira, the head of the institutes, said.

Omicron sublineages  mutated to evade immunity

  • As almost all South Africans either having been vaccinated against the coronavirus or having had a prior infection the current surge in cases means that the strains are more likely to be capable of evading the body’s defenses rather than simply being more transmissible, de Oliveira said.
  • There are “mutations in the lineages that allow the virus to evade immunity,” he said in a response to queries. “We expect that it can cause reinfections and it can break through some vaccines, because that’s the only way something can grow in South Africa where we estimate that more than 90% of the population has a level of immune protection.”
  • South Africa is seen as a key harbinger of how the omicron variant and its sublineages are likely to play out in the rest of the world. South African and Botswanan scientists discovered omicron in November and South Africa was the first country to experience a major surge of infections as a result of the variant.
  • The new sublineages account for about 70% of new coronavirus cases in South Africa, de Oliveira said in a series of Twitter postings. 
  • “Our main scenario for Omicron BA.4 and BA.5 is that it increases infections but that does not translate into large hospitalizations and deaths,” he said.
  • So far, the sublineages have been detected in seven of South Africa’s nine provinces and 20 countries worldwide.