Thursday , June 1 2023

New virus variants – there is probably no danger to the effect of the vaccine 01/08/21


BERLIN (dpa-AFX) – A ghost with the cryptic name B.1.1.7 is around. This variant of coronavirus has now been detected in several countries, including several times in Germany. In its current state, it is probably more contagious than previous forms. It would be even worse if vaccines against B.1.1.7 and similar variants, such as 501Y.V2, recently demonstrated for the first time in South Africa, were less effective or no longer effective. But this is unlikely, as a current analysis confirms.

Consequently, at least the Biontech / Pfizer vaccine is also effective against certain variants of the coronavirus. The antibodies in the blood of 20 people who had been vaccinated were examined, according to a study by the American pharmaceutical company Pfizer and the University of Texas, which has not yet been published in a journal and was examined by independent experts. . According to this fact, the vaccine will also achieve an efficacy of about 95% in the modified forms.

Variant B.1.1.7 was first detected in the UK in December. Similar to the 501Y.V2 variant that appeared in South Africa, it is characterized by changes in the genetic material that result in several changes in the so-called spike protein on the surface. With it, the virus attaches to the body’s cells to penetrate them. Spike protein is also the indirect target of RNA vaccines approved in Germany by Biontech / Pfizer and Moderna.

The agents stimulate the body’s cells to produce this protein. This leads the body to believe that there is an infection, the immune system is activated and, among other things, it forms antibodies against the protein. In the event of a subsequent infection, they should help to quickly remove the virus by binding to the spike protein and marking it as “hostile” for defense.

Theoretically, it would be quite conceivable that changes in the spike protein of Sars-CoV-2 lead to antibodies that are no longer able to bind. The vaccine would then be ineffective. But so far there is no evidence to that effect. Researchers are optimistic that this will remain the case. Because a vaccinated person’s immune response is not so easy to get rid of.

One reason for this is that after vaccination against the crown, people produce not only one type of protective antibody against the spike protein, but many different ones, as explained by Berlin virologist Christian Drosten in the NDR podcast. Experts are talking about polyclonal antibodies. This mixture of antibodies can attack a large number of spike protein binding sites. Therefore, individual modifications of this protein should initially have a reduced effect.

There are many who suggest that “the changes so far have not been so substantial that the vaccines that come now do not work,” says Hajo Zeeb, head of the Prevention and Evaluation department at the Leibniz Institute for Prevention and Epidemiology Research in Bremen.

In addition, there are limits on 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. “He doesn’t have an unlimited number of possibilities to get rid of antibodies through change, because he has to do his job.” This includes attachment 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 T cells are often not even affected by such mutations. Most vaccines also evoked a very good T cell immunity, so Drosten.

Drosten does not expect Sars-CoV-2 to have a flu-like effect – experts say about gene drift – for several years, when the coronavirus became endemic. Influenza vaccines need to be readjusted again and again due to changes in viruses.

In principle, if there are a large number of new infections, variants with mutations that are favorable to them are more likely to appear and spread, says Jörg Timm, head of the Institute of Virology at the University Clinic in Düsseldorf. “Once vaccination has started now, there may be options against which the response to vaccination does not provide sufficient protection.” Therefore, cases should be examined very carefully in which an infection occurs despite vaccination.

But even if the worst case scenario should occur, the corona variants should no longer respond to the vaccine: “In fact, RNA vaccines in particular can be modified from a relatively easy technical point of view. However, it should then be clarified how they look. renewed approval of a modified vaccine “. / vf / DP / fba

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