These variants that science watches | Coronavirus

A recombinant can arise when several variants infect the same person at the same time. For example, a person in a bar where people are infected with two different variants could inhale particles from these two viruses. If these viruses then infect the same cell, it could be that the variants interact during replication and mix their genetic material to form new combinations: recombinants.

Everything mixes like a soupillustrated by virologist Benoit Barbeau. What it does is diversify the virus. Some [recombinants] not only can it be more highly transmissible, but it can also better evade the immune response.

The first recombinant SARS-CoV-2s were discovered in 2020, but with the high levels of transmission in recent months, it is not surprising that many recombinants appear, explains this professor from the Department of Biological Sciences at UQAM. Of the 17 recombinants discovered so far, 12 were discovered in 2022. There is fertile ground for these recombinantspoints out.

Two letters are used to name recombinants, the first of which is an X.

First there was XA, discovered in December 2020 in the UK, which was a combination of Alpha variant and B.1.177 variant.

There was also the recombinant XD, commonly known as Deltacron, who was a starter for a few weeks. This recombinant, first discovered in France, never became dominant and its range was limited.

For now, experts have their sights set on the recombinant XE, a combination of Omicron’s BA.1 and BA.2 subvariants.

There are other recombinants that combine these same subvariants, such as XQ in the UK, XG in Denmark, XJ in Finland and XK in Belgium.

However, it is XE that seems to be causing the most community broadcast, especially in the UK, where more than 1000 cases have been reported. It has also been reported in India, China, and Thailand; a handful of cases have been detected in Canada.

For now, researchers believe that XE should not escape the immune response provided by the vaccine, but they are monitoring the situation closely.

On the other hand, UK data suggest that XE has a 10% to 20% higher growth rate than BA.2. Remember that BA.2 was already 30% to 50% more transmissible than the original Omicron variant (BA.1).

It is believed [que les recombinants] circulating are more transmissible but not more dangerous. We need to be aware that this virus has not yet evolved. »

A quote from Benoit Barbeau, virology expert

Even more members in the Omicron family

Not only recombinants are being closely monitored. To date, about twenty variations of BA.2 (Omicron subvariant) have been discovered. Most of them have undergone mutations without consequences. On the other hand, some new members of the Omicron family raise some concerns about their increased community transmission.

This is especially true of BA.2.12.1 and BA.2.1, first discovered in the United States, especially in New York State.

Although BA.2 is still very much present in our southern neighbors, it is losing ground to BA.2.12.1, which is currently experiencing exponential growth.

In fact, according to the Centers for Disease Control and Prevention (CDC), BA.2.12.1 caused 19% of new infections in the United States last week, compared to 11% of cases in the United States. previous week and 7% three weeks ago.

According to New York authorities, BA.2.12.1 would be approximately 25% more contagious than BA.2 and would also have led to an increase in the number of hospitalizations. Experts believe that the mutations observed in BA.2.12.1 protein S (spike) would allow the virus to enter cells more quickly and could affect the immunity conferred by a vaccine or an infection.

Two other Omicron sub-variants, BA.4 and BA.5, are circulating at low levels in other parts of the world, such as South Africa, Botswana, Germany, and Denmark.

So far, these subvariants have not caused a rise in hospitalizations, but experts say it remains to be seen whether these subvariants are more virulent or not and whether they will lead the BA.2.

The more cases there are, the more mutations there will be.

If the appearance of all these subvariants may seem disturbing, Mr. Barbeau reminds us that it is natural for the virus to mutate.

According to Mr. Barbeau, all these variations are a sign that SARS-CoV-2 continues to evolve and has not said its last word. It is a reminder that we are in a pandemic with ever new players.

In addition, experts have been repeating this for months: the more cases of COVID-19 there are in the world, the greater the risk of seeing a variant that is not only more contagious but also more dangerous.

Will the virus lose its vigor with the mutations?

It is unknown at this time what he will do after leaving the post. Will they have the same level of danger? We cannot answer this question. Some say yes, but more data is needed. »

A quote from Benoit Barbeau, virology expert

While we can’t predict all the surprises that SARS-CoV-2 will bring us in the coming months, Mr. Barbeau says it is absolutely necessary to continue to detect these new and recombinant variants not only through PCR screening but also wastewater analysis.

He adds that despite the appearance of all these variants, vaccination is still the best way to protect yourself from the severe symptoms of the disease.

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