Nature paper: Homologous 3 doses of vaccine is expected to reduce the risk of severe infection in Omi kerong

Beijing, January 30 (Reporter Sun Zifa) The latest online publication of a virology research paper by Chinese scientists in the internationally renowned academic journal Nature said that the study found that people who received 3 doses of CoronaVac had a sero-positive antibody transfer rate of 95% against the Omicron variant of the new coronavirus. This study shows that homologous 3 doses of inactivated vaccine are expected to reduce the risk of severe illness caused by infection with the Omikejung variant.

Screenshot of the Nature paper webpage.

To test whether the serum of people who received 2-3 doses of the Koxing vaccine could neutralize the Omiljung variant, wang Xiangxi, co-corresponding author and researcher at the Institute of Biophysics of the Chinese Academy of Sciences, and colleagues collected blood samples from 120 people, of whom 60 received 2 doses and 60 people received 3 doses of the vaccine, four weeks after their last vaccination, and no participants in the study had previously been infected with the new crown virus. They found that the seroant antibody positive rate was 3.3% and 95% of 2 doses and 3 doses, respectively, supporting the need to apply the 3 doses of immunization regimen.

Notably, the neutralizing antibody levels induced by 3 doses against the Ormi kerong variant were still higher than the neutralizing antibody levels produced against the Delta mutant strain produced by vaccinating two doses of inactivated vaccine compared to the serum neutralizing antibody levels of the population receiving the two doses of the Coxing vaccine. In previous studies, real-world data in Countries such as Brazil and Chile showed that two doses of inactivated vaccine had a critical care efficacy of more than 80% against Delta mutant strains. Therefore, the researchers believe that receiving three doses of inactivated vaccine helps to provide effective critical care protection against the Omiljung mutant strain.

The team then isolated 323 monoclonal antibodies from the samples obtained 3 doses. Of these, 24 strains were found to be effective in neutralizing Omilon and 4 antibodies were selected for structural analysis, two of which (XGv347 and XGv289) were highly effective against Omilon. The team determined the interaction of these antibodies with the Omiljung spike protein and identified a mutation in the spike protein (G446S) that is more resistant to a class of antibodies that bind to the receptor binding domain.

Structural comparisons show that XGv347 is similar to a neutralizing antibody (A23-58.1) that is effective against several strains of the new coronavirus and similar to the epitope (antibody binding site) targeted by another neutralizing antibody (S2K146), while S2K146 is effective against other coronavirus B branch B (i.e., a group of viral branches to which the new coronavirus belongs).

The latest study, which structurally analyzed antibodies isolated from people who received 3 doses of the Coxing vaccine, help explain the potency of specific antibodies on the Omiljung variant. These findings could help develop vaccines that are effective against many coronaviruses. At the same time, identifying and identifying antibodies that are broadly protective against multiple viruses may help develop a generic vaccine strategy against branch B of coronavirus B. (End)