When many of us thought that we could finally relax and forget about covid, two new sub-variants of the coronavirus, known as BA.4 and BA.5, are leading some countries to return to being on alert.
These two subvariants of omicron are considered the most contagious so far, because they have mutations that allow them to evade immunity.
This means that neither existing vaccines nor previous covid infections prevent its transmission.
According to the World Health Organization (WHO), in June the BA.5 subvariant was detected in 62 countries and BA.4 in 58.
The agency also reported that BA.5 became the main source of covid in the world.
In some countries these two subvariants are causing new waves of contagion.
However, the scientific journal Nature noted that “so far, the latest omicron variants appear to be causing fewer deaths and hospitalizations than their older cousins,” referring to the original coronavirus, which emerged in Wuhan, China, and the alpha, beta, gamma and delta, which followed.
Here we explain what is known so far about BA.4 and BA.5.
What exactly are the subvariants BA.4 and BA.5?
Since it first appeared in late 2019, the virus that causes covid-19 (SARS-CoV-2) has been mutating or changing form.
New genetic versions that keep appearing are called variants.
There have already been some variants, such as alpha and delta, causing massive waves of infection around the world.
Some variants mutate slightly, generating subvariants, as in the case of ómicron, which has already generated five versions.
The two most recent are BA.4 and BA.5, first detected in South Africa in January and February 2022, respectively.
According to experts, they spread much more rapidly than the other subvariants of omicron and that is why they are promoting a new increase in cases.
Where are they circulating?
According to the WHO, evidence indicates that the BA.2 subvariant of omicron, which caused an increase in infections in late 2021 and early this year, is disappearing, with more and more cases of BA.4 and, above all, of BA.5.
The latter is today the main source of covid contagion in the world.
At the end of June, it represented 43% of omicron cases, the variant responsible for 94% of infections globally.
This variant is believed to be responsible for an increase in infections in various parts of the world.
The most affected region, according to the latest WHO epidemiological report, is Europe, where cases increased by 33% in the week of June 20 to 26, compared to the previous week.
It was the third consecutive increase in infections, after reporting drops between March and May.
The largest increases in cases were seen in Romania (665%), Spain (531%) and Kazakhstan (167%).
There were also strong increases in Italy (61%), France (37%) and Germany (23%).
Europe is the region hardest hit by BA.4 and BA.5. GETTY IMAGES
The Americas region is also seeing a rapid increase in cases, with 1.3 million new infections (a 14% increase) in the same period.
“16 countries reported increases in the number of new cases of 20% or more, with some of the largest proportional increases seen in Canada (131%), the Falkland/Malvinas Islands (122%) and Bolivia (110%),” it notes. the WHO report.
Brazil, the most populous country in Latin America, had a 37% increase in the number of cases, and Mexico 47%.
Although in percentage terms the increase in new infections in the United States was lower, 5%, in nominal terms it was the country in the region that added the most cases: more than 700,000 in that single week.
According to the Los Angeles Times, the growing dominance of what it called “new, ultra-contagious subvariants of omicron” in California is “prompting growing concern from health officials that the next few weeks could see significant spread and increased hospitalizations.” “.
The Middle East is also the epicenter of a new wave, with an increase of 47%, while the South-East Asia region registered 32% of new cases.
In contrast, in the rest of Asia and in Africa, infections have been declining.
Are they more dangerous variants?
Like other subvariants of omicron, BA.4 and BA.5 are believed to cause mild illness and are not as deadly as other variants of the coronavirus.
But its rapid ability to spread could affect the most vulnerable populationsleading to more hospitalizations.
Therefore, experts are not sure how much countries will be affected.
The evidence so far does not show a clear trend.
In Europe, despite the fact that infections increased by 33%, deaths fell by 5%, according to the latest UN report.
Meanwhile, in the Americas, where the rise in infections was lower (14%), deaths from covid increased by 11%, with the highest increases recorded in the US, Brazil and Chile.
One of the theories is that in the places where these two subvariants circulate the most, herd immunity is generated, which protects the most vulnerable in society.
It is estimated that these variants are not more lethal than the previous ones, but they are much more contagious. GETTY IMAGES
Can I get these subvariants if I’ve already gotten sick from other versions of omicron?
There is evidence that BA.4 and BA.5 appear to be infectious even for people vaccinated or who recently had a covid infection with other types of omicron.
But even if they don’t prevent contagion, they do prevent serious illness.
“If you have been vaccinated and had covid (of the previous omicron subvariants), you will have at least some protection against BA.4 and BA.5,” Paul Bieniasz, a professor at Rockefeller University in the USA, told BBC Mundo. USA, specializing in viral evolution.
However, he clarified that “it is not complete protection.”
How can we protect ourselves against these two new variants?
As with other variants of covid, the risk of serious illness remains higher for people who are older or have underlying health conditions.
That is why the recommendation for these people is to continue using protection measures such as social distance or the chinstrap.
And if you are going to meet someone from a vulnerable population, it is recommended that you take a test to check that you do not have the virus, even if you do not have symptoms.
Finally, doctors say it’s vital that people continue to get vaccinated with the recommended number of doses to avoid severe disease.
Vaccines are still the best way to protect yourself. GETTY IMAGES
Why do variants continue to appear?
Viruses make identical copies of themselves to reproduce, but they don’t always do it perfectly.
They make mistakes that change the genetic blueprint, resulting in a new version of the virus.
If this gives the virus a survival advantage, the new version will thrive.
The more chances the coronavirus has to make copies of itself in us, its hosts, the more chances there are for mutations to occur, so BA.4 and BA.5 are probably not the last to cause covid.
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