The geneticist spoke about the negative scenario of a pandemic with a low rate of vaccination
Chimeric genome
Unlike the Chinese strain, which appeared a year and a half ago, new variants of the coronavirus like “delta” or “gamma” have a shorter incubation period, said a virologist at the N.F. Gamalei of the Ministry of Health of Russia, Professor Alexander Butenko.
“When certain changes occur in the genome of the virus, there is a possibility that vaccines based on the Chinese antigen – and these are all vaccines currently in existence – are somewhat less effective. But the fact that their opportunity is limited does not mean that it is not expressed, therefore vaccination is welcomed as the main way to combat the development of a pandemic, ”he told Gazeta.Ru.
Nevertheless, the emergence of a strain against which vaccines will be powerless cannot be completely ruled out, he said.
“Theoretically, such mutations are possible that will cause the formation of strains that are very different from the original, and then a new vaccine will have to be prepared,” the virologist explained.
According to Butenko, the more people become infected with the virus, the more likely mutations are. In addition, against the background of the appearance of antibodies in humans, the virus will try to adapt to them. Coronavirus mutations will never end, this is its property.
At the same time, in theory, strains can mix with each other – recombine, said Pavel Volchkov, geneticist, head of the MIPT genomic engineering laboratory.
“For this, a person needs to be infected with several strains at once, and that this act of recombination occurs at some specific point. As a result, a chimeric genome of coronavirus may be formed, where one part of the genome will be from one strain, the other from another, ”he explained.
At the same time, at the moment there is not a single publication in which the emergence of a “chimeric genome” would be recorded. “This does not mean that this does not exist and that recombinations do not occur. Probably, they are occurring, they just do not yet produce an effective resistant strain that would give a new type of “delta + gamma”, for example, “added Volchkov.
Aggressive Russian strain is not excluded
Strains are formed constantly in all countries where active transmission of infection continues, explained the associate professor of the Department of Infectious Diseases in Children of the N.N. N.I. Pirogov, infectious disease doctor Ivan Konovalov.
“Where there is no sufficient population immunity, there is a high chance of the virus acquiring those mutations that will be responsible for higher virulence, that is, aggressiveness. We see that similar variations of the virus have been identified in Britain, Brazil, India, South Africa. And so far in Russia has no collective immunity, we can expect the emergence of more aggressive options on the territory of our country, “he said.
He called vaccination the most effective and safest method of controlling the pandemic, but while it is limited in terms of coverage of the population, other protective measures need to be used – wearing masks, maintaining social distance, isolation.
If we talk about the strains separately, then the Indian “delta” is more aggressive than the Brazilian “gamut”, said infectious disease doctor Evgeny Timakov.
“It is unlikely that the gamma strain will supplant the delta, because it is more aggressive. However, the gamma strain is more contagious than previous strains of the coronavirus. New strains in different countries will continue to appear and be modified, ”he said.
When traveling to other countries and regions, people should be aware of the degree of risk: they may not only get sick with already known strains or not receive proper medical care in time, but also pick up an unknown strain, Timakov warned.
“In resorts where people from different regions or different countries intersect, like in Turkey, the situation is on the verge of a lockdown,” the infectious disease specialist said.
Since May, when the “delta” appeared in Russia, the rate of the pandemic in the country has increased, added Pavel Volchkov.
“How events will develop further depends on the rate of vaccination. If by the end of summer we can vaccinate 60% of the population, we should expect a more or less favorable scenario, if 50% – relatively less favorable, 40% – even less, and so on, ”he predicts.
