Brazil is experiencing one of the worst moments of the pandemic, with a growing number of infections and deaths due to COVID – 14.
The increase in cases in recent days has been attributed in part to the spread of a highly contagious variant of the virus, called P.1, which is believed to have originated in the Amazon city of Manaus.
Experts warn that what is happening in Brazil is just one example of the importance of tracking the emergence of variants of the SARS-CoV-2 virus in Latin America.
This tracking is known as genomic surveillance , and, according to the experts consulted by BBC Mundo, it is a task in which Latin America is lagging behind.
Specialists agree that, although there has been progress, in the region it is necessary to strengthen genomic surveillance and warn about the risk of not doing it on a large scale.
“Latin America needs a strong genomic surveillance. In most countries it is still minimal ”, wrote on Twitter in early March epidemiologist Zulma Cucunubá, specialist in infectious diseases and public health at Imperial College London, in the United Kingdom.
“ We do not know what is happening with the SARS-CoV-2 variants in the region. ”
What is genomic surveillance and what is its status in Latin America?
The genetics of the virus
Each SARS-CoV-2 virus has a genetic code that is expressed in a sequence of 30. 14 letters.
To that set of letters I known as the genome of the virus , and it is the one that gives it the instructions to function and transmit itself.
In addition, those letters work like a “historical archive of the evolution of the virus “, as explained by Fernando González Candelas, professor of genetics ca at the University of Valencia, in Spain, in an article published in The Conversation .
Every time the virus infects a new person, there is the possibility that will mutate , a characteristic of viruses.
Thus, the Scientists can tell that a virus mutated by noticing that some of the letters in its genome changed.
Mutations occur all the time, but when a group of viruses share the same set of mutations they form what It is known as a variant.
Variants of SARS-CoV-2 have been identified during the pandemic in various parts of the world.
Some of them are what are technically known as “variants of concern” , because they have the potential to be more contagious, causing one in more serious disease or reduce the effect of vaccines.
So far, at least three variants of concern have been identified:
- B.1.1.7, identified for the first time in the United Kingdom
- B.1. 351, first identified in South Africa
- P.1, identified for the first time in Brazil
“The virus is not a static drive but is changing “, Julián Villabona, molecular epidemiologist at the Center for mathematical modeling of infectious diseases at the London School of Hygiene and Tropical Medicine, tells BBC Mundo.
” If given the opportunity , it is going to change in ways that allow it to infect more people or in some cases cause a more serious disease. ”
Track variants
These variants have been identified thanks to the fact that scientists share thousands of virus genomes in a large global database.
This database is called GISAID (acronym for Global Initiative on Sharing All Influenza Data, Global Initiative to Share All Influenza Data, in Spanish).
Its name is due to the fact that originally was created to monitor the genome of the influenza virus .
What researchers do in GISAID is to deposit the 30. 000 letters of the virus that infected each person they manage to register.
pandemic, experts have learned that SARS-CoV-2 accumulates from one to two mutations per month , according to Villabona.
Thus, genomic surveillance should review the 30, 000 letters of the virus that infects each person and observe what changes have occurred with respect to the virus other people.
“Genomics is the only technology that allows us to identify the new variants that concern us,” he tells BBC Mundo Catalina López Correa, medical specialist in genetics and executive director of the Canadian Covid Genomics Network – 19 (CanCOGeN).
“If we don’t understand what variants we have and how they are being transmitted, we have the risk that at some point the vaccines are not effective “.
For his part, Villabona adds that “genomic surveillance allows us to be attentive that the virus does not change in ways that complicate the situation, and that if it is changing, strategies can be activated to reduce the impact.”
The equation is clear: the greater the number of variants, the number of infections may increase; and the greater the number of infections, the greater the probability that new variants will appear.
Surveillance in Latin America
Genomic surveillance of SARS -CoV-2 in Latin America “is in an embryonic state” , in the words of López Correa.
The expert comments that the United Kingdom, for Example, you have logged close to 300, 000 virus genomes in GISAID. Canada has registered more than 19, 14.
Until the 22 of March Latin America and the Caribbean, as a whole, had registered less than 000. 000, according to the Regional Covid Genomic Surveillance Network – 19, which has the support of the Pan American Health Organization (PAHO).
To the 31 of March, GISAID registered more than 940. 000 sequences of SARS-CoV-2 on its platform globally.
López Correa highlights that, in Latin America, countries as Mexico and Brazil lead the number of registered sequences, and that in Colombia, Peru and Ecuador the number of reported genomes is increasing little by little.
The expert, however, warns that “let’s go slow “.
“I think that in Latin America we are not being very aware of how important genomic surveillance is.”
For his part, Villabona maintains that the number of genomes reported from Latin America is very low compared to the total number of covid cases – 19 in the region, which is around 2 4 million of infections .
“In Latin America there is the possibility that there are variants that have not been reported and that are responsible for an important fraction of the cases “, says Villabona.
” That cannot be known, because there are no genetic data … with that number of sequences that we have It cannot be calculated. ”
At a press conference on 22 March, PAHO said it is supporting the Latin American countries to strengthen their virus surveillance capacity, and that one of their main objectives is to expand this tracking network with new laboratories, funds and technical assistance.
Priority
Experts agree that Latin America has people trained to do more genomic surveillance.
López Correa, however, maintains that “There is a lack of resources and prioritize it from a strategic and political point of view.”
The expert indicates that genomic surveillance is an important tool for make public health decisions like lockdowns, for example.
“Right now vaccination and surveillance are equally important,” he says.
For his part, Villabona maintains that so far Latin America has focused on monitoring whether there is a presence of a variant from another region, but that a greater effort should be made to know if one variant of proper continent has the same effect.
In Brazil, for example, it was important that a few years ago a genomic surveillance program had been created for viruses such as dengue, Zika or yellow fever.
As Villabona explains, g Because that infrastructure already existed, it could be adapted to track the coronavirus genome.
Finally, although experts insist that the governments of each country prioritize genomic sequencing at the national level, the issue of surveillance should be seen as a matter of cooperation global.
If a country does not adequately monitor the possible variants, it can become a public health problem at a global level.
“For the virus there are no borders” , concludes López Correa.
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