OREANDA-NEWS. Two doses of coronavirus vaccines from Pfizer and Moderna do not provide protection against the omicron strain six months after the second vaccination, according to a study by American scientists, a preprint of which was published on the bioRxiv resource.

"Six months after the second dose, the plasma of none of the studied vaccinated individuals showed neutralizing activity against the omicron strain," the study said.

According to the study, after the second dose, the neutralizing activity of antibodies was reduced by 30 times upon contact with the omicron, compared with other strains. However, after the booster dose, the indicators decreased only 14 times. Moreover, the third dose provided protection from the omicron for more than 90% of the participants.

According to scientists, these data prove the need for revaccination to provide protection against omicron.

The omicron coronavirus strain, which differs from previous variants in a large number of new mutations, was identified in African countries in November. The World Health Organization, following an emergency meeting, decided to classify the new variant of the coronavirus as causing concern. Experts believe that even those who have been ill and vaccinated can become infected with it, and the symptoms range from fatigue to headaches and body aches.