Frankfurt According to study data, the Covid-19 vaccine from Biontech and Pfizer is still effective against the new Omikron variant after three doses. After only two doses, the two companies assume a lower effectiveness, as they announced on Wednesday. Preliminary laboratory studies have shown that blood sera from people who have been vaccinated twice have a significantly lower neutralizing potential against Omikron.
A double vaccination could probably still protect against a serious illness. Three doses could neutralize the variant. The data also showed that a booster dose increased neutralizing antibody titers 25-fold compared to two doses.
Biontech and Pfizer were already working on a variant-specific vaccine against Omikron. They assume that this will be available by the end of March, should an adjustment be necessary for a higher and longer-lasting protection.
“These initial data suggest that a booster vaccination can still offer sufficient protection against a disease of any severity caused by the Omicron variant,” said Biontech boss Ugur Sahin. “Large-scale vaccination and refresher campaigns around the world could help us better protect people around the world and get through the winter.”
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Sahin had said last week that he thinks it likely that vaccinated people will have significant protection against serious illnesses caused by Omikron. This should be even more pronounced after the third booster vaccination. Basically, however, he believes that a new vaccine against the new variant will be required from a certain point in time, the only question is when.
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The variant, which was first discovered in South Africa and is now spreading worldwide, has triggered an alarm. Scientists were particularly concerned about the high number of mutations in the virus’ spike protein. Initial studies from South Africa and Germany on immune protection against the Omikron variant showed a 40-fold reduction in the neutralizing effect of antibodies.
The neutralization of the Omikron variant “decreased very much” compared to an earlier Covid strain, said Alex Sigal, professor at the Africa Health Research Institute in South Africa, on the basis of preliminary results.
The virologist Sandra Ciesek from the University Hospital Frankfurt published data on the effectiveness of the vaccines against the new variant on Wednesday and came to the conclusion that “the development of a vaccine adapted to Omikron makes sense”.
The virologist Christian Drosten from the Charité spoke of very important data. “Doesn’t look good for a double vaccine. Third dose necessary “, he wrote on Twitter. But even three months after a booster vaccination with Biontech, Ciesek only sees a neutralization of 25 percent with Omikron compared to 95 percent with the still predominant Delta variant and speaks of a neutralizing effect of the antibodies that is up to 37 times reduced compared to the delta variant.
With a double vaccination six months ago with Biontech, Moderna and a cross-vaccination with Astrazeneca / Biontech, an antibody reaction was not even measurable.
The Afrika Health Research Institute in South Africa tested the blood of twelve people who were vaccinated with the vaccine from Biontech / Pfizer in a laboratory. A 41-fold decrease in neutralizing antibodies against the Omikron variant was observed.
The Omikron variant was still able to neutralize the blood of five of the six people who had been vaccinated and previously infected with Covid-19. “These results are better than I expected. The more antibodies you have, the greater the chance that you will be protected from Omikron, ”explained Sigal. The preliminary data have not yet been reviewed by peers.
While neutralizing antibodies are an indicator of the body’s immune response, the scientists believe that other types of cells, such as B and T cells, will also be stimulated by the vaccines and help protect against the effects of the coronavirus. In addition, the preliminary data do not suggest that the vaccine is less able to prevent serious illness or death.
US expert Fauci expects higher transferability
“The data show that even people who have been vaccinated twice often do not have enough antibodies to neutralize Omikron,” said Carsten Watzl, Secretary General of the German Society for Immunology. “Only after a booster or after a combination of infection plus two vaccinations are enough antibodies available. That means we’ll see even more breakthrough infections with Omikron. The incidences could therefore increase significantly again. “
According to leading US infectious disease expert Anthony Fauci, preliminary results suggest that the variant is likely to have a higher degree of communicability but is less severe.
The World Health Organization (WHO) classified Omikron as a “worrying variant” on November 26th. So far, however, there has been no evidence of a necessary adaptation of the existing Covid-19 vaccines to the Omikron variant, said their emergency director Mike Ryan.
More: Omikron variant is fueling the need for genetic diagnostics