The World Health Organization says the new XBB.1.5 variant is the most transmissible identified so far

The identification of a new type of coronavirus that may be behind the increase in Covid cases in the United States sets off an alert for the rest of the world, according to the World Health Organization (WHO).

It is called XBB.1.5, a descendant of XBB, and has been identified in at least 29 countries. In the USA, it has replaced the omicron variants BA.5 and BQ.1, which account for more than 75% of samples in some places in the country, such as New York.

In a presentation made by the WHO Technical Group on Wednesday (4), the epidemiologist and responsible for the Covid group in the entity, Maria Van Kerkhove, said that “the variant is the most transmissible so far due to the mutations it has accumulated” and that it has an immune escape, that is It is able to escape the immunity conferred by vaccines and previous infections.

According to the epidemiologist, last Tuesday (3) the WHO technical committee met to discuss the rise in Covid cases in China, but also ended up discussing the rapid spread of XBB.1.5, which is already showing signs of concern for the committee.

“The more circular this variant is, the greater the chances of it changing, and with that we expect new waves of infection worldwide, although we still have no indication of the potential severity or the clinical picture,” he said.

Kerkhov also said that XBB.1.5 may grow in many countries around the world, but delays in sample processing make it difficult to assess the scale of the scenario. She said there is a clear growth advantage to the variant in the northeastern United States, where it has managed to become dominant compared to other variants.

In a study published December 13 in the specialized journal Cell, scientists warn of the escape of antibodies from sub-variants of the BQ and XBB strains, including BQ.1, identified in Brazil in October, and XBB.1, which triggered their emergence. . to the rolling swing.

According to the research involving scientists from Columbia University and the University of Michigan (both in the US), the level of antibodies in people who received three or four doses of the vaccine produced against the original virus in Wuhan (the Chinese city in which the coronavirus was initially identified) Those vaccinated with Omicron-adapted bivalent had almost zero antibody to XBB.1.

Alleged vaccine escapes with Omicron’s BA.4 or BA.5 variants also failed to prevent new infections by XBB.1.

The same concern arose with monoclonal antibodies, a treatment used to treat serious patients with Covid, which had practically no effect against the variants.

Rapid development of new sub-variants [de BQ.1 e XBB.1] and their accumulation of mutations, particularly in the S. [espícula usada pelo vírus para invadir as células] Similar to what we saw when omicron first appeared in early 2021, raising alarm about how it could weaken the effectiveness of existing Covid vaccines and monoclonal therapies,” the paper’s authors write.

(Anna Potalo/Folhabers)