This is what we must take into account in the face of a possible fourth wave of COVID-19 by BA.2 in Peru

On November 24, 2021, when it was expected that the decline of the delta variant would bring the end of the pandemic stage and the start of the endemic phase of the COVID-19the South African Minister of Health made an announcement that once again changed the course of the pandemic.

and was immediately considered a concern variant. It was about omicron. Being baptized so early with the Greek letter, its scientific name, BA.1, went more or less unnoticed.

In a few weeks, omicron, compared in its contagiousness with the virus of measles, spread rapidly, and the unthinkable happened: it displaced the hitherto highly contagious delta variant.

The omicron family

The importance of remembering that formed around March 2021. The three BA variants derived from the virus original from Wuhan.

Despite having common mutations, which is why they are grouped as a family, these variants, known as the family omicronare as different from each other as the alpha, beta, gamma, or delta variants are from each other.

thought to be present in the parent variant, from which came BA.1 (omicron), which has 20 additional mutations; BA.2, which has 27 additional mutations; and BA.3which has 13 extra mutations.

The vast majority of these 39 mutations of the mother variant are in the area of ​​the spike which, as we know, is what the virus uses to enter cells and contains the antigenic areas, against which the antibodies produced by the cells are directed. vaccines and natural disease. The rest of the mutations are distributed in other parts of the virus structure, and could play an important role in the transmissibility of the virus. coronavirus.

“The Hong Kong case has shown that the omicron variant is far from being a harmless virus.”

The two most important characteristics of the viruses of the family omicron are its high contagiousness and the way it enters cells. Despite producing a lower viral load in the nose than the original Wuhan variant,

On the other hand -and this is a feature that has practical implications as yet unknown-, like the virus that causes SARS (which disappeared in 2004), the omicron family completely enters the interior of the infected cell, while all previous variants enter the cell, fusing their membrane with that of the infected cell.

Clinical behavior of the virus

Based on data from Europe, the US and other countries in which omicron has become prevalent, the disease causes mild symptoms, such as sore throat, malaise, body aches, and low-grade fever.

However, the case of Hong Kong has shown that omicron is far from being a harmless virus. In this regard, until January 31, 2021, 213 deaths had been registered in that city, a number that increased to 3,993 as of March 13, 2022. That is, during the first 10 weeks of March, there were 17.7 times more deaths in Hong Kong than during the first two years of the pandemic.

One of the reasons for this health misfortune is that the Hong Kong Government did not emphasize the vaccination of its population, because for the first week of March, . These data show us that if omicron – and apparently also BA.2 – infects vulnerable people, the virus can be deadly.

The advancement of BA.2

It is estimated that the resurgence of the pandemic in Europe is a consequence of the BA.2 variant, which has displaced omicron.

In the US, genomic surveillance data showed that from March 13 to 19 the 35% of cases it was caused by BA.2, and it was 22% the week before. It is estimated that, and it is feared, as happened with ómicron, that it will saturate health services.

The possible new wave by BA.2 in Peru

BA.2 was found since February in Peru, and the behavior of this variant in a population with high rates of natural infection and relatively high levels of vaccination with two doses is unknown.

In this context, it is worrying that vaccination coverage with a third dose does not reach 40% of the population. If it causes a fourth wave, BA.2 may disproportionately affect older adults and people with comorbidities.

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