According to the latest estimates released by the Centers for Disease Control and Prevention, the omicron subvariant BA.2.12.1 is poised to become dominant in the US, accounting for an estimated 36.5 percent of all US SARS-CoV-2 cases.
The subvariant's ascent is the latest rapid succession of omicron subvariants, from the sky-scraping peak of cases from the initial omicron subvariant BA.1 in January, to the current bump driven by the subvariant BA.2, which achieved dominance in March. As before, the reason for the viral usurping is that omicron subvariants continue to evolve advantages: BA.2.12.1 has a transmission advantage over BA.2, which had a transmission advantage over BA.1, which had a significant advantage over delta.The impending reign of BA.2.12.1 raises concern for yet another wave of infections and poses questions about how effective future omicron-specific vaccines could be.
The good news is that current vaccines are still protecting against severe COVID-19, and that the CDC and other health experts are actively monitoring this. The subvariant seems to be able to evade immune protections.
The data was posted online Monday, and it showed that strong neutralization evasion was found against people who had also had breakthrough BA.1 infections. In the study, participants were given Sinovac's CoronaVac vaccine, which had 50 percent efficacy in early observational studies.
50 people who had received three CoronaVac doses and recovered from a BA.1 infection were looked at by the researchers. The researchers found that the levels of neutralizing antibody against BA.2 were about 1.86 times lower than for BA.1. As researchers moved on to newer subvariants, neutralizing antibody levels were lower for BA.2.12.1, compared with BA.1, and eight times lower against BA.4 and BA.5.
AdvertisementPreliminary data out of South Africa echoes the latter finding. The researchers found that people who had recovered from a BA.1 infection had lower levels of neutralizing antibody than people who had not recovered. Researchers still saw a loss in protection, despite the fact that the gap in neutralizing antibody levels was narrowed by either a Pfizer/BioNTech vaccine or a J&J vaccine.
The data all point to the possibility of more re infections from newer omicron subvariants, particularly in people who are unvaccinated or not up to date on their vaccinations. This could cause more waves of infections in the US and around the world, though experts don't expect another wave like the BA.1 surge in January.
Some of the designs of second-generation vaccines may target BA.1, which raises concerns. Moderna announced last month that it believed a bivalent vaccine would be a winning strategy to provide broader, longer- lasting protection.
"Our latest bivalent booster candidate, mRNA-1273.214, which combines the currently authorized Moderna COVID-19 booster with our [BA.1] omicron-specific booster candidate, remains our lead candidate for the fall 2022 Northern Hemisphere booster," Moderna CEO Stéphane Bancel said in a statement at the time.The new data suggests that the vaccines may not be strong enough to protect against BA.2, BA.4, and any other omicron subvariants down the line.
Omicron sublineages have started to target the humoral immunity that was caused by omicron itself, including the humoral immunity that was caused by post-vaccine omicron infections, according to the authors.
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