Status: 01/26/2021 9:43 a.m.
Even in places where herd immunity has already been assumed, people are again infected with mutated versions of the corona virus. What makes the mutants so contagious?
Among the many questions and uncertainties that SARS-CoV-2, Covid-19 and the current pandemic bring with them, the mutations that are spreading from England, South Africa and Brazil are arguably the most pressing at the moment.
New virus variant from Brazil
In Brazil in particular, a new virus variant called P1 is pushing hospitals to the limit again. In some areas, especially in Manaus, there was already herd immunity and believed that they had survived the worst after three quarters of the population had been infected with SARS-CoV-2 last year. But now people are infected again and become seriously ill.
How mutations arise
Individual mutants in SARS-CoV-2 were discovered last spring – but now many small mutations can be observed. Whether corona, flu or other viruses: in order to develop mutations, the pathogens first have to get into a body cell, which they reprogram in such a way that they duplicate the genetic information of the virus and produce new viruses.
There are always mistakes, the mutations. They can change the virus as a whole, but many of them have no noticeable effect on the virus and its behavior. However, if a mutant helps the virus to reproduce, transmit or escape the immune system better, this is a competitive advantage over other viruses. Thus, the mutated variant prevails better and may even gain dominance in a region.
More contagious due to mutations in the spike protein
In the construction plans of the new variants in Brazil, England and South Africa, the mutations affect the so-called spike proteins. They work like keys: if the virus hits a human cell, it must first find the entrance, the keyhole, so to speak. With the earlier versions of the SARS-CoV-2, this process takes a relatively long time and does not always succeed. As a result of the mutations, the cones of the spike proteins contain other amino acids, which changes the properties of the virus. It thus has an additional tool with which it can dock faster and infect the cell – and is therefore more infectious.
In addition, the virus variant P1 seems to be better able to evade the attacks of the immune system thanks to an additional spike protein on the surface by blocking antibodies. Virologists speak of a so-called escape mutation. It comes into play when, as immunity increases in the population, the virus comes under pressure to evade the human body’s immune response.
Are the vaccines also effective on mutants?
Such virus variants could not only increase the risk of renewed infections after the illness has already been overcome, but also impair the effectiveness of the vaccines currently available. How resistant the new mutants actually are to the vaccines and to what extent these will have to be adapted in the future remains to be researched.
How can mutations be slowed down?
Control of the pandemic becomes even more difficult where the new variants predominate. In the worst case scenario, it will lead to more infected people and more deaths. Therefore it is now a matter of adhering to the known precautionary measures even more consistently and accelerating the vaccination programs – this could slow down further mutations.
