COVID-19: warn that a person can be infected with two variants at the same time

Brazilian scientists have confirmed that a patient can be simultaneously infected with two variants of the SARS-CoV-2 virus, which causes the disease COVID-19. Of discovery, researchers have warned that such a high viral load of different strains of the pathogen is circulating, which would provide the ideal conditions for further and more dangerous recombinations of the virus to take place.

At the end of November 2020, a genomic surveillance study was carried out on 92 patient samples from the state of Rio Grande do Sul, in southern Brazil. Scientists have identified two 30-year-old patients infected with the B.1.1.28 variant (E484 K), who emerged in Rio de Janeiro, but at the same time tested positive for the B.1.1.248 variants or B.1.91. virus. These are the first two cases reported in the world of co-infected patients. The patients had relatively mild symptoms and did not require hospitalization. Both patients have recovered. The discovery was published in the magazine Virus research.

In addition to the two cases of co-infection, by genetically analyzing the 92 samples, the researchers were able to characterize five different strains of the virus circulating in Rio Grande do Sul, and a new variant, called VUI-NP13L. “Although coinfections with viruses are known and have some recurrence, the discovery in Brazil adds an additional requirement to the management of the pandemic,” said Vivian Luchsinger., Institute of Biomedical Sciences of the Faculty of Medicine of the University of Chile, which did not participate in the study, according to the portal Scidev.NET.

“These co-infections reflect the strong simultaneous circulation of different lineages of the virus in a given geographic space”, explained to SciDev.Net Fernando Spilki, co-author of the study published in Virus scan and virologist from Feevale University, in the state of Rio Grande do Sul. This is very worrying, according to the specialist, because these are the conditions favorable to the recombination or the emergence of new species of the virus.

Genetic recombination occurs when two different viruses infect the same cell and replicate, generating a “progeny”. Unlike the new virus lines detected so far, which respond one by one to accumulated point mutations, this recombinant virus may have several genetic improvements, or evolutionary advantages, at the same time. “This may mean an evolutionary leap for the virus, making it stronger than other lineages,” Spilki pointed out. And if it’s stronger, it can also be more infectious or cause more serious conditions, and end up being the dominant strain, he added.

Although the researchers did not detect any recombinations in the samples studied, the risk of them occurring is high. And there would already be evidence. Scientists at Los Alamos National Laboratory in New Mexico, US, reported recombination during a webinar hosted by the New York Academy of Sciences in early February. These are believed to be the British and Californian strains, and are believed to be responsible for the increase in cases in Los Angeles, United States. If confirmed, it would become the first recombination detected during the pandemic.

It is also not known whether a co-infected patient can transmit both strains and what if one of them has higher transmissibility. It is also not known how common the co-infection is, but it is highly likely to occur elsewhere as well, Luchsinger said.

A previous study – still in the prepress phase, without peer review – found that the variants that appeared in Brazil are responsible for the latest increases in infections in their border countries. By imposing restrictions on movement between nations, as was the case in Uruguay and Argentina at the end of 2020, the strains have been genetically differentiated on either side of the border, adding more variants. For all the past, specialists recommend maintaining social distancing measures, wearing masks or chin straps and continuing to wash your hands frequently, constantly ventilate closed environments, such as offices and schools, and also to limit minimum transfers. But they also call for vaccinations. “Vaccination should not be done only at the national or regional level, but at the global level to achieve control of the pandemic,” warns Luchsinger. For this reason, he added, the richer countries must necessarily help the poorest to immunize their populations.

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