Virologist Netesov: “It turns out that there are already two or three varieties of coronavirus”
One of it is more infectious, but less pathogenic, and the other is less infectious, but more pathogenic.
Sergei Netesov, the head of the Laboratory of Bionanotechnology, Microbiology and Virology at Novosibirsk State University, the former head of the Vector laboratory, where a test for the new coronavirus was developed, gave an interview to Reminder. Novye Izvestia cites the most interesting fragments from it.
In New York, crowding in the streets, especially in Manhattan, is the same as in Moscow inside the Garden Ring. Communication between people is very active: residents are used to going to a cafe or restaurant two or three times a day. There are a lot of conditions for the transmission of infection, hence the epidemic rampage. We will have the same picture, especially in Moscow, I very much suspect it, although I do not want to.
About the deficit of tests
Test systems need a lot more than it seemed at the beginning. It quickly became clear that some key reagents were coming to an end. Do not call them, so as not to cause additional price increases and speculation. Now they are in short supply not only in Russia, but also in the whole world. They are needed for all PCR-based test systems. And if the capacity for the production of test systems is increased ten times in the USA and Europe, then, accordingly, the supply of reagents there, and not only to Russia, is also growing. These reagents are manufactured in India and China, and our borders are now half closed. And as far as I know, these very issues have been resolved all last week. So one large task breaks up into a mass of small ones. Thanks to private companies, it may be possible to close the shortage of imported reagents.
Mortality is considered by dividing the number of deaths from this virus by the number of cases with a confirmed diagnosis. But at the same time, you need to understand: today we tested the sick, but what will happen to them - will they survive or die - you will only know in two weeks. Russia is now in the initial stages of the epidemic. In fact, we scored 80% of new cases in a week. And we consider mortality for those patients who became infected two, three or four weeks ago. Our figures do not yet reflect the real picture. In China, out of 80 thousand patients, 3-4 thousand patients remained. There you can already calculate mortality (it turns out 4%, - Reminder). But even in Italy it’s too early to count, because they have just overcome the peak of incidence.
About the varieties of coronavirus
Yes, it is now gradually becoming clear that there are two or even three varieties of the virus. One is more contagious, but less pathogenic, and the other is less contagious, but more pathogenic. So far, only a couple of studies have been published, with the authors cautiously writing that there is such a trend in three varieties. In theory, this should be the case with this virus, because for him the human population is like a medium of selection. If we isolate a patient with a severe form, he practically does not spread the virus further. An asymptomatic carrier spreads the virus freely, and most people infected with it will also have an asymptomatic infection. That is, a less pathogenic variant is selected. In the history of mankind, this has already happened to some pathogens. This is a natural process, which, however, can go very slowly.
About infection methods
Flu studies have shown that up to 40% of people become infected through finger contact, and not through coughing and sneezing. On April 10, in Novosibirsk, 18 people were identified. For two, the situation is incomprehensible: where they became infected is unknown. They certainly did not contact the patients. Now it’s being checked whether they were in contact with their relatives, and if it turns out that they didn’t contact with their relatives, there’s only one hypothesis that they took the same pen somewhere as an infected person. But we only see the tip of the iceberg, because we don’t know how many asymptoms we have.
About the spread of the virus
How many percent of people should be immunized in order to develop collective immunity depends on the degree of contagiousness - the virus spread coefficient. It shows how many people on average infect one infected person. For example, in influenza, the distribution rate is 1.4. And it is believed that it is enough to immunize 60% of the population so that outbreaks of influenza quickly fade. In the case of measles, it is 95%. But in measles, the distribution coefficient is much higher - 12-14. The current virus has about 3. Approximately, we can say that in the case of coronavirus, the proportion of immunized should be more than 50%. But even at 30%, the process will slow down, as happened in China. Apparently, in Hubei, about 40 percent of the population is already immunized, so they quarantined them and even started holding football matches. So 30-50% - this will be the threshold after which the epidemic will decline.
About the vaccine
There is an example of polio virus, which we have virtually eradicated with vaccines. Many other viral infections are mild - two to three days. But they still exist in nature. The question is, due to what and how they are saved. In the case of polio viruses, we understood this 15-20 years ago. They are excreted from the human body with feces, where they are much more than in the blood. Then they fall into the sewers and live there for up to six months. It is for this reason that we are now moving from a live vaccine from polio to inactivated: so that the virus does not stand out after vaccination with feces and other people do not become infected. How effective the vaccine against the new coronavirus will be can only be judged when we get the current vaccine. And it will become clear in six months.
About the future
The coronavirus is called new, but in fact it is not something new. Studies show that even the ancestors of our own four coronaviruses are found in bats. The process we have now witnessed is not the first for nature, but at least the fifth. We must come to terms with the fact that the more we are, the more there will be viruses that infect us. And study animal viruses much more intensively in order to be ready to repel new invasions.