The third booster / booster dose Covid-19 successfully increases antibody levels so that they can now neutralize the Omicron variant of the coronavirus, which is not the case with the two doses sufficiently, confirms a British laboratory study involving a Greek diaspora scientist.
Researchers at the Francis Creek Institute in London, including Dr. George Cassiotis, head of the Retroviral Immunology Laboratory and professor of virology at the Imperial College School of Medicine, made the publication Antibodies produced in people who have taken only two doses of Oxford / Astra Zeneca or Pfizer / BioNTech are less able to neutralize Omicron than the Alpha and Delta variants. Indicatively, in those who took two doses of Pfizer, antibody levels were found to be about three times lower than Omicron than after Delta after two doses. In those who had taken two doses of Astra Zeneca, anti-Omicron antibody levels were too low to be measured.
The researchers, who analyzed 620 blood samples from 364 people, found that antibody levels dropped within the first three months after the second dose, but the third dose restored their levels effectively to neutralize Omicron.
In people who did all three doses with Pfizer / BioNTech, the mean levels of anti-Omicron antibodies after the booster dose are similar to those against Delta after two doses. Overall, the antibody levels are almost 2,5 times higher than Omicron after the three doses, compared to the two doses.
Higher levels of anti-Omicron antibodies were also found in people who took two doses of either Pfizer or Astra Zeneca and also showed symptoms. Covid-19, compared to those who did not have such symptoms of infection.
Although antibody levels alone do not predict the effectiveness of vaccines, they are a very good indicator of protection against severe Covid-19. New study confirms three vaccine doses are needed to maximize protection against serious illness and hospitalization risk due to Covid-19.
The researchers also confirmed that the synthetic monoclonal antibody Xevudy (sotrovimab), used to prevent and treat patients at risk of serious illness, could kill Homicron.
Source: RES-EAP