Indian scientists have published the results of the study.
Indian scientists from the National Institute of Virology in Puna, with the support of the country’s Ministry of Health and the Department of Health Research, conducted scientific work on the study of new strains of SARS-CoV-2 and concluded that the recently appeared variant of P.2, first discovered in Brazil, has increased pathogenicity, that is, causes a more severe course of COVID-19. However, so far this has been proven only on laboratory hamsters.
During the year of the COVID-19 pandemic, the SARS-CoV-2 virus accumulated serious mutations that led to the emergence of new strains. The first worrisome variant of B.1.1.7 was identified at the end of December in the UK and has now spread to 62 countries in Europe, Asia, the United States, etc. Today, this variant has about 17 mutations.
The next dangerous variant (B.1351) appeared in South Africa (today it has 21 mutations). He is already traveling in Africa, Europe, Asia, and Australia.
In January, the P.1 line appeared which is of the greatest concern today (17 mutations). This variant has been widely distributed in the Amazonas state of Brazil and has also been recorded in the Faroe Islands, South Korea, and the United States. Less is known about it yet, including how contagious it is and whether it causes a more severe course of the disease. However, some experts blame him for the outbreak of repeated infections in the Brazilian city of Manaus, where, it would seem, collective immunity was already achieved (by the time of his arrival, 70% of the inhabitants were ill there). In addition, Brazil reported a different version of the line – P.2.
Today, public health experts around the world are closely monitoring the three most rapidly spreading variants of SARS-CoV-2: “British,” “South African” and “Brazilian.” They not only have an increased ability to infect but are also able to bypass the immune defenses after previous strains, which threatens the effectiveness of vaccination, among other things. However, there has been no scientific data about the P.1 and P.2 lines so far: no one has yet evaluated their properties in the laboratory.
At the same time, the Brazilian Ministry of Health and doctors on the ground after the spread of P. 1 and P.2 reported a much more severe course of the disease. The main focus has been on the Brazilian P.1 strain, which has largely displaced P.2 in Brazil and spread to many countries around the world. P.2, which is losing out to other dangerous strains, is unlikely to spread particularly widely. The discovery by the Indian scientists at the same time reveals a possible near-term prospect of the virus changing its virulence if P.2 mutations appear in the next-generation strains.
Indian scientists tried to evaluate the pathogenicity of SARS-CoV-2 virus variants in animal models. 9 Syrian hamsters (these animals were already used to assess the pathogenicity of other variants of the coronavirus) were artificially infected with the usual variant of the virus, and another 9 with the P variant.2, which was received from two international travelers returning to India from Britain and Brazil. The hamsters were watched for a week. As a result, it turned out that P.2 causes greater weight loss, carries a higher viral load in the respiratory tract, and remained active longer in the lungs. In hamsters infected with the usual variant of the virus, lung damage was mild, in those infected with P. 2-severe, with a specific picture of the lesion, including hemorrhages in the lung tissue.
P.2 becomes the first variant with experimentally confirmed higher pathogenicity. Experiments with other dangerous strains did not show an increase in pathogenicity. B.1.1.7 and B.1.617.2 are associated with a more severe course of the disease, probably due to inoculation with large doses of the virus, since dangerous strains create a higher viral load in the upper respiratory tract. The combination of high viral load and increased pathogenicity makes Brazil P.2 particularly dangerous. In addition, experiments have shown that the P.2 line is twice as resistant to the two docks of the anti-coronavirus vaccine compared to the older strains.
The authors of the study call for increased genomic surveillance of the spread of new Brazilian strains, which, fortunately, are still detected infrequently. “It will also allow you to quickly assess their prevalence around the world. In an environment where the effectiveness of existing COVID-19 vaccines against new strains is still unknown, we still need to continue to monitor non-drug measures, such as the use of masks, physical distancing, hand hygiene, and avoiding public gatherings, which will prevent the transmission of these new variants to a large extent,” the authors note.
Meanwhile, a well-known virologist and corresponding member of the Russian Academy of Sciences told, to date there is no convincing scientific data that the Brazilian strain is more pathogenic for humans, that is, it causes severe disease more often: “Data on greater pathogenicity for laboratory animals deserve attention, but the pathogenicity of the virus for different hosts does not always correlate. But it is worse neutralized by the antibodies of those who have been ill and vaccinated — about the same as the British one-and worse neutralized by the antibodies of those who have been ill and vaccinated. We don’t know exactly how much the risk of getting sick increases for these people. In general, they remain protected, but the risk of getting sick again, especially in a mild form, has become noticeably higher.”