COVID-19 can be more dangerous than previously thought. Scientists have suggested that the disease is a coronavirus that can switch from the active form of chronic. This is based on information on cases of re-infection, fixed in China last months. The virus can remain dormant latent form, as the human immune system does not have it under full control. Another hypothesis of the Russian experts is that a new strain mutates with great speed and people just don’t have time to develop antibodies to it, so ill again. Also, cases of re-infection may be associated with errors of test systems, the accuracy of which is high.
In February came the Information Bulletin of the state Committee for hygiene and public health of the PRC, which reported 195 cases of re-infection of recovered patients with COVID-19. Sometimes the infection occurred several hours after the delivery of the tests, which confirmed successful treatment.
This may mean that part of the diseased immune system for some reason does not produce natural protection against the virus, as occurs in people who have had other diseases. Our doctors can’t fully kill the infection that enters a latent form. As explained by the “News” the head of the laboratory of genomic engineering MIPT Pavel Volchkov, usually in the course of treatment the immune system completely destroys all infected cells and eliminates the virus in the blood. Recurrent symptoms suggest that the virus is still present in the human body.— One of the possible explanations of re-infection is that the patient, a transfer of disease from the acute to the chronic phase when the fluctuation in the number of viral particles in the body, — said Pavel Volchkov. — The virus may come back as the immune system during the acute phase of the disease took him under complete control and had infected large number of bodies. Thus, in order not to destroy the heavily infected tissue, the immune system selects the option of “living together” with the virus. There are already cases of death from so-called re-infection. In early March there were reports about the death of a 36-year-old resident of Wuhan. The first time the disease was discovered on February 12, the patient was hospitalized. The doctors fixed his minor symptoms and after two weeks of treatment was discharged. Again he was taken to the hospital on March 2, where he was on the same day he died.
The superfast mutation
Information about the reasons for what is considered re-infection must be scrutinized, while there are no accurate data, only hypotheses. However, a number of infections are characterized by long-term preservation of the virus in the body and various places of its localization, Danila Konnov, head of the infectious diseases department of the H-Clinic of the RUDN University, told Izvestia. For example, adenovirus in the first stages of infection is detected in the mucosa of the oropharynx and conjunctiva of the eyes. And in the final stage of the disease and after clinical recovery, it may be present in the feces for several weeks, ”the infectious disease specialist explained. – Here the answer to the question is important: if it is a re-infection, then it happened with the same strain or genetically distinct? If it is different, then the immunity developed against one virus may not work when infected with the second.This means that possibly leading several strains or virus shows surprising variability within such a short duration of the epidemic, said Daniel Konnov. Scientists already know that pathogens, particularly those containing DNA and RNA (they just owned COVID-19), with the copy itself, allow a large number of errors. This gives them the ability to mutate quickly, changing with the transmission from person to person. However, the theory about fast changes in the genome of the coronavirus requires careful confirmation.
The fact of detection of infection in the body is already recovered individuals does not necessarily mean recurrent disease. Perhaps, in this case, the disease is “hiding” and proceeds asymptomatic, told in conversation with “Izvestia” a senior researcher of the Institute of X-Bio TSU Maria Orlova.
Repeated infections can be due to the human inability to form long-lived antibodies to this pathogen, she said. — Also this may indicate the high ability of the virus to mutate. Both assumptions are quite alarming: if the information is confirmed, most likely, the vaccine efficacy will be low, and obviously she can’t be a hard barrier to the epidemic. Scientists admit that, if re-infection occurs error test systems. Associate Professor of Skoltech Georgy Bazykin considers that immunity acquired ill COVID-19 human, can hardly be alleviated in such a short time.
— Much more likely a technical error, — the scientist explained. — It was considered that there was a second infection when the presence of the virus in the patient is first determined by the test, then no, a few days later, it is revealed again. But the sensitivity of the test is not one hundred percent and could happen that he just “didn’t notice” strain.
Hypothesis error test-systems support and chair of the Department of Virology of the biological faculty of Moscow State University. M. V. Lomonosova Olga Karpova. Although she does not deny the possibility of being infection in the chronic form. Such persistent infection is possible (persistence is the ability of microorganisms that cause infection, how long to arrive in the human body without showing clinical symptoms. — “News”), but not yet shown for coronaviruses, — said Olga Karpova. — However, the first thought that comes is an error in the testing of infections in these 195 cases of re-infection in China. In any case, the situation requires further research. The coronavirus identified in more than a hundred countries. According to the latest data given on the website of the who, recorded 109 577 cases of infection, 3809 people were killed. That is a hundred people infected account for 3.5 of the dead. A further increase in mortality is possible, but unlikely under the conditions of quarantine measures and an increase in the effectiveness of treatment, said Stanislav Otstanov, lead researcher, deputy head of the laboratory for analysis of population health indicators and digitalization of healthcare at the Moscow Institute of Physics and Technology (MIPT).
– At the same time, the Middle East respiratory syndrome, also caused by a coronavirus (MERS-CoV), is less contagious, but it has a significantly higher mortality rate: 2494 infections (from 2012 to the present day) in 27 countries resulted in 858 deaths (34 deaths per 100 cases). Therefore, in the case of COVID-19, one should not give in to panic, the expert emphasized.
Earlier, WHO Director-General Tedros Adhan Ghebreyesus said that the threat of a pandemic of the new coronavirus becomes real with an increase in the number of infected. At the same time, he emphasized that this may be the first pandemic in history that can be controlled.