Omicron’s BA.2.12.1 substrate is expected to become dominant in the United States, currently accounting for an estimated 36.5 percent of all SARS-CoV-2 cases in the United States, according to the latest estimates Tuesday. released by the Centers for Disease Control and Prevention.
The rise of the variant is the latest in rapid succession of omicron subvariables, from the skyrocketing peak of cases of the first omicron subvariant BA.1 in January to the current bump pushed by the BA.2 variant, that dominance reached in March. As before, the reason for virus rape is that the ommicron subvariants continue to develop advantages: BA.2.12.1 has a transmission advantage over BA.2, which has a transmission advantage over BA.1, which has a significant advantage over BA. delta.
The approaching era of BA.2.12.1 raises concerns about a new wave of infection and questions about the efficacy of future Omicron-specific vaccines against incidental infections.
The good news so far is that current vaccines still provide strong protection against severe COVID-19, and BA.2.12.1 does not appear to cause more serious illness than BA.1 or BA.2 (despite the CDC) and other health problems. experts actively monitor this. However, the subvariant appears to be able to evade immune protection, especially that of a previous BA.1 infection.
dodge
With preliminary data published online Monday, researchers in Beijing found that BA.2.12.1 showed “strong neutralization evasion” against antibodies from vaccinated people who also had BA.1 infection. In the study, participants were vaccinated with Sinovac’s CoronaVac, an inactivated whole-virus vaccine, which showed approximately 50% efficacy in early observational studies in Brazil. (MRNA-based vaccines have shown approximately 95 percent efficacy in initial clinical trials.)
The researchers looked at neutralizing antibodies from 50 people who received three doses of CoronaVac and recovered from a BA.1 infection. By comparing levels of neutralizing antibodies to a group of coronavirus variants, the researchers found that neutralizing antibody levels against BA.2 were about 1.86 times lower than for BA.1. But things got worse when the researchers switched to newer subvariables: Neutralizing antibody levels were 3.73 times lower for BA.2.12.1, compared with BA.1, and eight times lower for BA.4 and BA.5.
The latter reflects preliminary data from South Africa, which Ars reported on Monday. There, the researchers found that in unvaccinated subjects who recovered from BA.1 infection, neutralizing antibody levels were 7.6-fold and 7.5-fold lower against BA.4 and BA.5, respectively, compared to levels against BA.1. While vaccination with the Pfizer/BioNTech or J&J vaccine narrowed the gap in neutralizing antibody levels, researchers still saw a loss in protection: 3.6-fold and 2.6-fold neutralizing antibodies to BA.4 and BA.5, respectively, compared to Bachelor degree 1.
Taken together, all data suggest the possibility of increased re-infections of the newer Omicron subvariants, particularly in unvaccinated or unvaccinated individuals. This could lead to more waves of infection in the US and around the world, although experts don’t expect another skyrocketing wave like the BA.1 surge in January.
The anxiety
It also raises concerns about second-generation vaccine designs — some of which could target BA.1, at least in part. For example, last month, Moderna announced its belief in a bivalent vaccine. Attacking two copies of the virus at once would be a winning strategy to provide broader, longer-lasting protection.
“The newest bivalent enhancer candidate, mRNA-1273,214, which combines the currently authorized Moderna COVID-19 enhancer with [BA.1] Stéphane Bancel, CEO of Moderna, said in a statement at the time that the Omicron booster candidate remains our lead candidate for fall 2022 in the Northern Hemisphere.
But new data suggests that BA.1-based vaccines may provide poor protection against BA.2, BA.4, BA.5 and all other ommicron subvariants.
“Unlike the time when omicron first appeared, subspecies of omicron have begun to target humoral immunity [antibodies and other adaptive responses] caused by omicron itself, including humoral immunity induced by omicron infection after vaccination, the authors of the new Beijing study wrote. Not the ideal antigen to induce broad spectrum protection against ommicron emerging substrains. †