Coronavirus: the Rio de Janeiro variant was detected in a local sample and studies are still needed to know its clinical implications

Last week, researchers from the Argentine Inter-institutional Genomics Project of
SARS-CoV-2
(COUNTRY) announced that they had detected a marker of the variant of
coronavirus identified in
Rio de Janeiro
(the S_E484K mutation) in a sample from the
Greater Buenos Aires
taken between December 18 and 26. Although the finding was interesting, they explained, it would be necessary to sequence the entire genome to determine if the
virus
found shared a common origin with the Rio de Janeiro variant.

This is what scientists from the Anlis-Malbrán Institute, they just confirmed it. “Of the last genomes we sequenced between November and December, we found one in which we were able to identify the six mutations corresponding to the Rio de Janeiro variant,” Josefina Campos, coordinator of the institute’s Genomics and Bioinformatics Platform, told Télam.

According to Claudia Perandones, scientific-technical director of Malbrán, when the new variants of the coronavirus were reported in the United Kingdom, the researchers sequenced 135 genomes. “We did not find them until December 20,” Perandones says. “This week we made 40 more, which we finished yesterday afternoon and among which there were five samples of international travelers who had returned from Europe. In these we did not find any of the variants, but among 34 samples from the province of Buenos Aires and the city we found one corresponding to a person who had no travel history with the six mutations that make up the variant of Rio de Janeiro “.

The relevance

Although it is important to monitor it, Not much is yet known about the clinical impact that this variant may have. “The caution is circumstantial and significantly less than that inspired by the data we have from the UK and South Africa. preprint that was presented about this finding from Brazil was very little discussed and has not been followed up until now – highlights Humberto Debat, virologist at INTA and member of the PAIS collaboration. It is based on the sequencing of 180 SARS-CoV-2 genomes. It appeared in October or November, and suddenly it began to make up a significant percentage of the sequenced genomes, but the total number is very small. In the case of the United Kingdom, we are talking about thousands and thousands of data that support greater transferability. The same happened in South Africa. That is not in the data for Brazil, so you have to be much more careful in how the arrival of this variant is communicated. Usually, one assumes that they all have the same behavior as the canonical virus, unless proven otherwise. The increase in the transferability of the British was something out of series, it was a great surprise. The data we have from Brazil is much worse. “

For Mariana Viegas, leader of the PAIS project, there was a great possibility that this lineage would enter the country. “This variant has a mutation that is associated with a decrease in neutralization with monoclonal antibodies and convalescent sera, and that is why it draws attention, but that has no implication in terms of transmissibility, effectiveness, severity of the condition,” he says. You just have to pay attention to it because more mutations associated with this could have a correlate in the escape of the virus to the antibodies. so far it doesn’t imply anything about the response to the vaccine. “

“In Brazil, it is the one with the greatest circulation; epidemiological studies must be carried out to see if it is associated with certain behaviors of the virus,” adds Elsa Baumeister, head of the Malbrán Respiratory Virosis Service. And Josefina Campos clarifies: “It is normal that there are variants of the virus, and there are several associated with international tourism. It still cannot be said that it is circulating in the country, we have to continue analyzing to see if we find it in a greater number of samples. “

To learn more about his behavior, Perandones yesterday had a conversation with the epidemiologist from the University of Rio de Janeiro, Amilcar Tanuri. “He told me that they are carrying out studies to determine if it has a higher transmissibility – he says -. There are two publications that propose, based on a theoretical model, that this mutation could condition the virus the possibility of evading the neutralizing response [del sistema inmune], but this has not yet been corroborated neither in vitro nor in vivo. “According to Tanuri, it would already constitute 40% of the samples sequenced in Rio de Janeiro and was detected in people between 2 and 80 years old. However, it is worth asking if this is representative of what happens in Rio or if there is any bias due to the relatively small number of samples.