Specialists from Skoltech, the Institute for Information Transmission Problems named after V.I. A.A. Kharkevich RAS, First State Medical University named after I.I. Pavlova, N.I. Smorodintsev and the 31st city hospital of St. Petersburg.
A patient suffering from malignant lymphoma contracted the coronavirus in April 2020 while undergoing chemotherapy at the hospital. However, not after two weeks, as usually happens, or after a month, the PCR test for coronavirus did not give a negative result …
The so-called persistent-positive type of illness sometimes occurs in people with suppressed immune systems. Not only did the woman suffer from cancer, the situation was aggravated by the fact that before the infection, she underwent chemotherapy, which further weakened her body.
The researchers report that during May-July, the PCR test in their patient showed a negative result, but this does not mean that she did not suffer from coronavirus at that time. This is a common history where the virus is not detected in the upper respiratory tract, but is diagnosed in the lungs and blood vessels. In addition, the woman had all the symptoms corresponding to the coronavirus.
In August, this patient’s PCR became positive again. According to the doctors who observed it, it was precisely persistence – a prolonged “falling asleep” of the previous virus followed by “awakening”. The woman did not have the opportunity to get infected again.
– This is the first case with such a long course of the disease, – I ask Nikolai Kryuchkov.
– No, not the first. It is unique in its analysis of the properties and structure of the virus itself. She got infected with one type, and then they found 18 of his mutations (not to be confused with strains). Scientists have done sequencing (decoding of the coronavirus genome) many times, comparing it with a large library of virus sequences obtained in different countries. It turned out that over a long period of time, the virus evolved within one organism.
– The paper talks about two mutations inherent in those found in the organisms of Danish minks infected with coronavirus. What does this mean?
– Previously, scientists have already identified one of the types of “mink” mutations in the body of another patient with immunosuppression (suppressed immunity). Until recently, it was believed that a combination of two such coronavirus mutations was characteristic only of minks. In this case, it was proved that the populations of minks and people with reduced immunity are somewhat similar to each other, include the same mechanisms for the development of the disease.
Another noteworthy fact: experts have noticed that the rate of development of SARS-СoV-2 mutations in the organisms of weakened people is several times higher than the rate of mutation in the normal human population.
All this confirms the fears that the population of people with immunodeficiency, including HIV-infected people, people with autoimmune diseases and cancer may play an important role in the evolution of coronavirus.
– In what direction will this evolution be directed?
– In the direction of strengthening its properties, negative for people. The main ones are the high degree of infectiousness and replication (reproduction in the body). The third property is a high ability to escape from the influence of antibodies, immunity to vaccines.