How effective is the fourth dose of the coronavirus vaccine and can it protect against infection with the omicron strain? A new study on medRxiv sought to answer these questions.

The scientists analyzed data from 300 healthcare workers and 400 volunteers who were vaccinated with 4 doses of Pfizer and Moderna vaccines. As it turned out, this number of vaccinations was able to prevent COVID-19 disease in only 30% of cases with the Pfizer vaccine and 11% of cases with Moderna.

According to the scientists, the fourth dose of RNA vaccines brought immunoglobulin levels to the same high level as after the third dose. However, this had no effect on the increased incidence of mild or asymptomatic coronavirus infection.

The scientists said these results were due to features of the new Omicron strain, which consists of 37 mutations that have changed the structure of the SARS-CoV-2 envelope. These changes made the virus immune to most known monoclonal immunoglobulins, rendering all existing vaccines ineffective.

According to the study, the findings indicate the need to develop a new generation of vaccines as soon as possible.