As of: December 8th, 2021 3:31 p.m.
Initial studies on the effectiveness of current vaccines against Omikron indicate a weaker defense against the new variant. Experts emphasize that the booster vaccination is all the more important in order to generate enough antibodies.
Laboratory tests on the effect of corona vaccines against Omikron indicate a weaker defense reaction. The virologist Sandra Ciesek from the University Hospital Frankfurt published the first results of the study on Twitter, which showed a significantly reduced antibody response to the new variant.
“The data confirm that the development of a vaccine adapted to Omikron makes sense,” wrote Ciesek. South African experts had already presented similar data the day before, according to which the antibody response in people vaccinated against Omikron is weaker.
Immune response reduced 37 times
However, Ciesek also pointed out that it was not possible to read from their evaluation whether vaccinated people were protected from a severe course at Omikron. Because the immune response is based not only on antibodies, but also, for example, on T cells.
The antibody response against Omikron is reduced by up to 37 times compared to the Delta variant – there is also a reduction in people with a booster vaccination. In her study, even three months after a booster vaccination with BioNTech, Ciesek sees only 25 percent neutralization with Omikron compared to 95 percent with the still predominant Delta variant. With a double vaccination with BioNTech or Moderna six months ago and a cross-vaccination with AstraZeneca / BioNTech, an antibody reaction was not even measurable.
“Doesn’t look good for someone who has been vaccinated twice”
The virologist Christian Drosten praised Ciesek’s survey and again emphasized the need for a booster vaccination. “Doesn’t look good for someone who was vaccinated twice. Third dose required,” wrote Drosten on Twitter. The data presented have not yet been reviewed by specialist colleagues and have not been published in a specialist magazine.
BioNTech / Pfizer: Third dose ensures neutralization
The vaccine manufacturers BioNTech and Pfizer made similar observations on the effectiveness against Omikron. Preliminary laboratory studies showed that after two doses of vaccine there was significantly less neutralization against Omikron, announced the two companies. According to this, however, three doses of the vaccine could neutralize the variant. The data also showed that a third dose increased the neutralizing effect 25-fold compared to two doses.
In order to examine the effect of a vaccine against a certain variant of Sars-CoV-2, researchers usually do so-called neutralization tests. It is checked how many antibodies a vaccinated person has in the blood that can bind to the virus variant and thus switch it off. The actual protection of vaccinated persons cannot be determined with this, however, clinical studies with thousands of test persons or evaluations of the ongoing infection process would be necessary.
African study with similar results
Researchers at the Africa Health Research Institute in South Africa published preliminary data on Tuesday on the effectiveness of the BioNTech / Pfizer vaccine against Omikron. According to the results, a considerable antibody response was measurable in vaccinated persons who were also infected. “The more antibodies you have, the greater the chance that you will be protected from omicrons,” the researchers said. These results have not yet been published in a specialist journal either.