A study gives hope: The vaccine from Biontech / Pfizer apparently has a long-lasting protective effect. Photo: David Young / dpa
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(Photo: dpa)
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“That shows a really robust immune response,” said co-principal Rachel Presti of the Washington University School of Medicine in St. Louis. Carsten Watzl from the Leibniz Institute for Labor Research at TU Dortmund University (IfADo) agrees with this assessment. “That is very gratifying. But whether and to what extent a long-term immunity can be derived from this is open, ”says the immunologist, who was not involved in the work, with a view to the actual protective effect of the vaccination.
It is known that the mRNA vaccinations reliably protect against Covid-19 for at least six months. However, it is unclear how long the protection lasts beyond that. In order to clarify the immunological processes, the team led by the infectiologist Presti and the immunologist Ali Ellebedy examined healthy people after the two vaccine doses given three weeks apart.
The preparation is injected into the upper arm. In the weeks following the vaccinations, the researchers took samples from people several times from lymph nodes in the neighboring armpit. They examined these for so-called germinal centers: they form the B memory cells of the body’s defenses and quickly build up a targeted defense reaction in the event of an infection.
“Germ centers are the key to a long-term protective immune response. This is where our immune memory is formed, ”explains Ellebedy. The researchers analyzed samples from ten participants that were taken twelve weeks after the second vaccination dose. In eight of them they found germ centers with B cells targeting the pathogen, as they report in the journal “Nature”. “That’s a good sign,” says Watzl. “The study offers a unique
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In addition, the researchers analyzed blood samples from 41 people who had been vaccinated, eight of whom had previously been infected with Sars-CoV-2. The antibody concentration generally peaked one week after the second vaccination and the antibodies were effective against all three corona variants examined: an original type, the alpha variant discovered in Great Britain and the beta variant found in South Africa. The delta variant played no role in the study.
Those vaccinated who had previously been infected with the pathogen had even higher values than the other participants. “If you’ve been infected before and then get vaccinated, the antibody levels get a boost,” explains co-author Jane O’Halloran. “The vaccination clearly has an additional benefit, so we recommend it to people who have had Covid-19 as well.”
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