Based on the fact that 20% of people with antibodies to coronavirus were officially recorded in Moscow, we can safely assume that 40-60% of the capital’s residents already have immunity to it, Pavel Volchkov, head of the MIPT genomic engineering laboratory, told Izvestia in an exclusive interview. This means that there will be no second wave of morbidity in the capital, the expert is sure. In addition, the virologist shared his views on exactly how the COVID-19 pandemic began. He is leaning towards the laboratory-origin version of SARS-CoV-2.
– Pavel Yuryevich, from your point of view, how many people in Moscow already have immunity to SARS-CoV-2?
– Recently, an article was published by Swedish scientists who conducted a study of T-cell immunity (“Sustainable T-cell immunity in recovering patients with the asymptomatic COVID-19 course”), the results of which I personally have long been waiting for. They analyzed a large number of biological samples by conducting an expensive ELISPOT analysis (Enzyme-Linked ImmunoSpot – T-cell detection method). It turned out that even those who did not have IgG antibodies had T-cell immunity. And there are two to three times more such people in the population than those with antibodies.
– What does it mean?
– If in Moscow officially recorded 20% of people with high titers of IgG antibodies, then you can safely add another 20-40% to this figure. It turns out that about half of Moscow residents are immune to coronavirus. They will not get sick anymore.
– Recently, articles appeared that showed that antibodies are lost …
“And that’s fine.” They must be lost. This always happens. There is a half-life of IgG, IgM, IgA antibodies. Their amount in the blood begins to fall six months to a year after meeting with the infection. There are so few of them that this amount cannot be detected by any test. What is the purpose of antibodies? Here the virus flew into the respiratory tract, infected a group of cells, created a small local focus (with a mild course of the disease). The immune system recognized these cells and localized them – it is like the city of Wuhan was closed in China. It turns out that a large number of antibodies do not seem to exist, but the immunity has formed and worked. However, it is concentrated in T- and B-memory cells. When the infection again occurs to a person, the immune system recognizes it, the cells will begin to produce antibodies.
– Does it make sense then to test for IgG antibodies?
– There is. This test is cheap and gives us a cutoff. This cut-off now is 20%. So we can multiply this amount by two to three times. It’s hard to say the exact number, for this you need to conduct a large-scale study using expensive ELISPOT analysis, as the Swedes did.
– Is it possible to say that the “herd” immunity, which everyone has been talking about for so long, has already taken shape in Moscow?
– For the multi-million peoples city, today’s figures in the region of 700 new infected per day indicate that it has formed. If we really had only 20% of the residents with immunity, then with open restaurants and shops, we would expect much more infected.
– But after all, on this figure (plus 700 people per day) you can stay for a long time. Or not? What is your prediction?
– I think this figure will now begin to decline and will reach zero at the end of August. It is clear that in the capital there will still be imported cases from regions that belatedly began to “pick up” the coronavirus.
– That is, the second wave will not be?
– For Moscow, it is already impossible. Now people who have formed natural immunity in the capital are 40-60%. If dynamics continues, their number will increase by the end of August to 80–90%.
– And in other cities of Russia, the second wave is possible?
– Only in those that are well insulated and where there is an extremely low level of infection. In big cities, definitely not. If you have already burned the grass, then the burned-out areas cannot be ignited again. Do you know how firefighters fight fire? They take and burn the front of the strip to stop the fire. This strip is our buffer immunity.
– But what about the fact that the virus mutates and the body may simply not recognize it?
– In any case, he does not mutate very quickly. Even the seasonal flu virus needs several years to re-infect you. And then in the event that part of its segments, and the flu has eight, will be re-sorted, that is, replaced by parts from another influenza virus. Coronavirus is single-segment – it cannot change that way.
“But can he recombine?”
– Maybe. But this event is more rare. It must take at least a couple of years for him to be able to return and cause you some kind of pathology. And still it will not be comparable to the first time. The immune system at least somehow recognizes it, which means it will work. And a secondary immune response will develop.
– The war of supporters of the natural and artificial origin of the coronavirus continues on the pages of the media, on social networks and blogs. What do you say at the moment when so many articles about its structure have already been published?
– I came to the conclusion that the probability of the virus overcoming the interspecific barrier without human help (accidental eating of a bat carrier SARS-CoV-2) is significantly less than the one that helped him. By help, I mean prolonged cultivation of the virus in the laboratory , the introduction of amino acid modifications, experiments to infect human cells if possible. All this is described in the same famous article of 2015 (Nature magazine, November 9, 2015). In favor of this hypothesis is also the location of the city of Wuhan.
– What do you have in mind?
– Wuhan is located in the very center of China. Bats are not found there. They live in the south, in Yunnan, on the border with Vietnam. It was there that they were caught to isolate new coronaviruses, which are now stored in the collection of the Wuhan laboratory. Although theoretically it can be assumed that they were brought thousands of kilometers to eat.
“But is it possible?”
“Yes, perhaps.” But in practice, traditional cuisine is therefore considered traditional because its menu contains local species of animals. If the virus “jumped” over a person when it was eaten, it would be found in Yunnan, on the border with Vietnam, Laos and Myanmar. From there the epidemic would have gone.
– Speaking about the origin of SARS-CoV-2, you can only handle probabilities?
“I’m afraid so.” In his sequence (letters of the genome. – “Izvestia”) it is not written: “I am made synthetically.” There are no obvious “donkey ears” – traces of a genetic engineering structure. But there is a hint of it. This is the famous furin insert, about which much has already been said.
“ But could she find herself in the genome of the virus during recombination?”
– Could. However, the likelihood of this event greatly increases, provided that you spend thousands of amino acid mutations. And the fact that American and Chinese scientists did this is proved by the 2015 article. If you look at the publications of these scientific groups, it becomes clear that they are very active, have worked a lot and for a long time with these viruses. In addition, the Chinese have a large library of coronaviruses, where the most genetically close sample of RatG13 has been discovered. He was brought to the Wuhan Institute of Virology from Yunnan in 2013. For seven years, when it was cultivated, passivated, he could naturally acquire a large number of mutations.In addition, science has made great progress in this regard over the past 10 years. We live in an era of synthetic biology, when you can synthesize some parts de novo, and then ensure a seamless insertion of such a synthetic part into the genome.
– That is, 10 years ago, you would definitely say, looking at the genome, what is inserted there?
– Exactly. And now there are technologies of extended genetic synthesis, when thousands of nucleotides can be synthesized. You simply send the letter sequence to a special company that synthesizes it and sends it back. The possibilities are huge now. In this way, whole libraries of new coronaviruses can be generated. Suppose there are 10 million of them there. And then you can choose the most promising one from them, assemble it using the reverse genetics method (which the group can do, as stated in the article in 2015. “Izvestia”) and test for the ability to infect human cells.
– That is, from your point of view, the probability that the virus has leaked from the laboratory is quite high?
– Yes. An argument in this favor is also that coronaviruses were not considered particularly dangerous for some time. And it was possible to work with them at the second level of protection (there are four of them, the third and fourth levels, according to the American classification, are especially dangerous. – Izvestia). Actually, this is understandable, because the initially isolated viruses could not pass from an animal to a person (to overcome the interspecific barrier) and, accordingly, from person to person.
– That is exactly what was affirmed at the very beginning of the pandemic …
– At the second level of protection, he could easily fly out and infect the scientist. And what’s important: it’s impossible to see right away. The funny thing is that the one who brought this virus out of the laboratory did not even understand that he did it. And may not have understood so far.
Source: Anna Urmantseva – IZVESTIA
Originally published: July 6, 2020
Note: the article was translated from Russian