One of the reasons for this is that after the corona vaccination, people not only produce a single type of protective antibody against the spike protein, but many different ones, as the Berlin virologist Christian Drosten explained in the NDR podcast. Experts speak of polyclonal antibodies. This antibody mix can attack a large number of binding sites on the spike protein. Therefore, individual changes to this protein should initially have little effect.
There is a lot to suggest that “the changes so far are nowhere near so substantial that the vaccines that are now coming do not work,” says Hajo Zeeb, head of the Prevention and Evaluation Department at the Leibniz Institute for Prevention Research and Epidemiology in Bremen.
In addition, there are limits to how much the spike protein can change, said Adam Lauring, an expert on the evolution of RNA viruses at the US University of Michigan, in a recent podcast. “It does not have an unlimited number of possibilities to escape the antibodies through changes, because it still has to do its job.” This includes attaching to body cells and allowing the virus to penetrate.
Drosten emphasizes another aspect. “Immunity is not just about antibodies.” So-called T cells, which are also part of the human immune system, have different binding sites than antibodies. At the beginning of an epidemic, the binding sites of the T cells are often not affected by such mutations. Most vaccines also evoked very good T-cell immunity, so Drosten.
Drosten does not expect Sars-CoV-2 to have an effect like the flu – experts speak of genetic drift – for a few years when the coronavirus has become endemic. Flu vaccines have to be adjusted again and again due to changes in the viruses.
In principle, if there is a high number of new infections, it is more likely that variants with mutations that are favorable to them will arise and spread, says Jörg Timm, head of the Institute for Virology at the University Clinic in Düsseldorf. “After the vaccination has now started, there may also be variants against which the vaccination response does not provide sufficient protection.” Therefore, cases should be examined very carefully in which an infection occurs despite vaccination.
“We will see more of such variants in the future,” says Isabella Eckerle from the Infectious Diseases Department at the University of Geneva. In order to be able to recognize them at an early stage, it is necessary to decipher the virus genetic material from samples on a broad basis. Andreas Bergthaler from the Research Institute for Molecular Medicine of the Austrian Academy of Sciences (CeMM) also emphasizes that the variants should be seen as a “wake-up call”.
The detection systems would have to be expanded and coordinated across Europe. But even if the worst case should occur and corona variants no longer respond to the existing vaccines: “In fact, RNA vaccines in particular can be technically modified relatively easily,” explains Timm. “It would then have to be clarified, however, what the renewed approval of a modified vaccine looks like.” Bergthaler emphasizes: “We must not believe that we have reached the end of the marathon with the vaccines.”
© dpa-infocom, dpa: 210108-99-942973 / 4
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Concern B117 virus variants pose threat vaccine effects knowledge