The efficacy of vaccines against the symptomatic Covid-19 infection caused by the new Omicron variant of the coronavirus is probably much lower than that of the previous variants, but the vaccines continue to provide significant protection against the risk of serious disease, especially make a third dose. This is the assessment of a new American scientific study, according to which if there are no massive doses of support, there is a risk that the number of cases and hospital admissions will increase in the future.
Researchers at the University of California, Berkeley, who pre-published medRxiv (not yet published in a scientific journal), according to Reuters, have developed computer models that incorporate data on older variants, on the other hand, take into account the first data on the effectiveness of the Pfizer / BioNTech vaccine against Omicron. Estimates of immunodeficiency are based on the levels of neutralizing antibodies and whether they decrease over time and against different variants of the coronavirus.
The models estimate that, after two doses of vaccine mRNA, the effectiveness of the vaccine in preventing symptomatic Covid-19 disease is only about 30%, compared with 87% for Delta. In fact, if more than four months have passed since the second dose, then protection against two doses of vaccine against the symptomatic infection “essentially disappears”.
But booster doses partially restore protection to about 48%, “which is similar to the 43% protection given to delta-immunized vaccinated people,” said lead researcher Professor Marm Kilpatrick.
Fortunately, according to him, “it is important that the protection against serious disease (due to Omicron) is much higher. We estimate that it is 86% in case someone has recently had a second dose of mRNA vaccine, 67% if it is too late his immunity has weakened, and 91% after the third boost. “
The researchers conclude that, in the case of Omicron, “the effectiveness of vaccines (two doses) against severe disease is significantly reduced for people with weakened immunity, while protection against infection, symptomatic disease and transmission (of However, third doses significantly improve these reductions, although they only restore protection to levels equivalent to those of individuals with weakened immunity to the Delta variant. the spread of infections and a significant increase in hospitalizations, unless there is a strengthening of immunity with widespread administration of booster doses. “
Link for scientific pre-publication: https://www.medrxiv.org/content/10.1101/2021.12.10.21267594v2.
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