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. 

Two new Omicron COVID subvariants BA.4 and BA.5 being analyzed by WHO

Only a few dozen cases of BA.4 and BA.5 have been reported to the global GISAID database, according to WHO

Authors: Jennifer Rigby Reuters April 11, 2022

The World Health Organization said on Monday it is tracking a few dozen cases of two new sub-variants of the highly transmissible Omicron strain of the coronavirus to assess whether they are more infectious or dangerous.

It has added BA.4 and BA.5, sister variants of the original BA.1 Omicron variant, to its list for monitoring. It is already tracking BA.1 and BA.2 — now globally dominant — as well as BA.1.1 and BA.3.

The WHO said it had begun tracking them because of their “additional mutations that need to be further studied to understand their impact on immune escape potential.”

Viruses mutate all the time but only some mutations affect their ability to spread or evade prior immunity from vaccination or infection, or the severity of disease they cause.

For instance, BA.2 now represents nearly 94% of all sequenced cases and is more transmissible than its siblings, but the evidence so far suggests it is no more likely to cause severe disease.

Only a few dozen cases of BA.4 and BA.5 have been reported to the global GISAID database, according to WHO.

The UK’s Health Security Agency said last week BA.4 had been found in South Africa, Denmark, Botswana, Scotland and England from Jan. 10 to March 30.

All the BA.5 cases were in South Africa as of last week, but on Monday Botswana’s health ministry said it had identified four cases of BA.4 and BA.5, all among people aged 30 to 50 who were fully vaccinated and experiencing mild symptoms.