A new study has shown that the antibodies produced by the first two doses of mRNA vaccines deplete over time and offer practically zero protection against omicrons. This further suggested that even successive infections after the 2-vaccine dose did not make a significant difference in the case of Omicron. However, the same team of scientists had earlier suggested that the mRNA vaccine booster dose produced effective levels of neutralizing antibodies against the COVID variant.
“Our new work shows that two doses of the mRNA vaccine does not provide protection against omicrons, and even having a successful infection on top of the vaccine does not help much. But our first The study showed that the booster could actually address the deficiencies of the two doses, said Shan-Lu Liu, senior author of both studies and a virology professor at The Ohio State University in the US.
“Serum samples were collected three to four weeks after the first vaccine dose, three to four weeks after the second vaccine dose, and six months after the second vaccine,” Liu said.
The new study, published in the journal Science Translational Medicine, examined antibodies in serum samples from 48 healthcare professionals with experimental versions of the parental virus and alpha, beta, delta and Omicron variants.
The authors suggest that neutralizing antibodies increase significantly after the second dose against every variant except the Omicron variant. John Evans, a Ph.D. student at Ohio State University.
Breakthrough Transition and Omicron
Although the findings suggested that a successful COVID-19 infection on top of vaccination led to increased immunity against most versions of the virus, only a person with a previous infection reached antibody levels that appropriately fight against Omicron. could do. “Overall, none in this study had good immunity against Omicron,” Liu said.
Liu noted a dramatic decrease in immunity six months after a dose of two vaccines, and the discovery of an earlier study that a booster protects against omicrons, highlights how important the third shot is to avoid infection.
“After the second vaccine dose, the effective neutralizing antibody against Omicron dropped 23-fold, but with the booster shot, immunity fell only three to four-fold—which is comparable to the previously reported booster effectiveness against the delta variant,” he said. said. added.
The experimental viruses were what are called pseudoviruses—a non-infectious viral core decorated with various SARS-CoV-2 spike proteins on the surface, structured to match known mutations in the types studied.
The results also showed that those who received the Pfizer mRNA vaccine produced almost two times lower levels of neutralizing antibodies than those who received Moderna Preventive. At later time points after vaccination, the levels of antibodies were significantly higher in men than in women against all types, the researchers said.
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