Omicron subvariants BA.4, BA.5 evade protection from earlier omicron infection

Preliminary data from South Africa shows that you can still be affected by omicron's subvariants.

The country is currently at the start of a new wave of infections driven by two omicron coronaviruses, BA.4 and BA.5. The New York Times reported that new omicron cases increased in the last two weeks despite a huge wave of cases from the initial BA.1 variant. The number of hospitalizations and deaths have increased.

The data posted online last week shows how the BA.4 and BA.5 omicron subvariants can be used to evade neutralizing antibodies. The study was led by Alex Sigal of the Africa Health Research Institute. They had samples from people who were unvaccinated and people who were vaccine recipients, and they all had the same BA.1 infections.

The unvaccinated people had lower levels of neutralizing antibody against BA.4 and BA.5 than against BA.1. The drop was 3.6-fold and 2.6-fold lower in people who werevaccinated.

Ever-evolving

The findings suggest that the latest omicron subvariants can affect protection from earlier omicron versions. The vaccine appears to dull the edge. The neutralization levels against BA.4 and BA.5 were five-fold higher for people who werevaccinated.

In places where vaccine coverage is low or vaccine protections are waning, BA.4 and BA.5 may have the ability to generate a new wave of cases.

In the US, where vaccination coverage is relatively high, but protection may be waning, BA.4 and BA.5 have only been found circulating at low levels so far. A different subvariant, BA.2, is currently dominating and causing an increase in cases. The difference between BA.2 and BA.4 and BA.5 is that BA.2 has three deletions and one deletion in the critical spike protein.

US experts are most closely watching another subvariant, BA.2.12.1, which has a similar profile as BA.2, but has two additional mutations. The same spot as a unique mutation in BA.4 and BA.5 is where one of the mutations in BA.2.12.1 is located.

While BA.2 is still the dominant variant in the US, BA.2.12.1 is gaining ground. According to the Centers for Disease Control and Prevention, BA.2 accounts for an estimated 68 percent of the cases in the US.