Covid-19 on the rise: From XBB to BF.7, new Omicron variants explained

Covid-19 cases are on the rise around the world. According to the World Health Organization (WHO), the 'variant of concern' at the moment is the Omicron variant, which includes its subvariants.

A discussion held by WHO's Technical Advisory Group on SARS-CoV-2 Virus Evolution (TAG-VE) recently focused on how the evolution of the variant is currently unfolding — in particular, the public health implications of the rise of some variants, like XBB and BQ.1.

XBB

According to the health organisation, XBB is a recombinant of BA.2.10.1 and BA.2.75 sublineages. It has a global prevalence of 1.3% and it has been detected in 35 countries. It noted "some early evidence on clinical severity and reinfection risk from Singapore and India", but added that the variant has not yet been consistently associated with an increase in new infections.

While further studies are needed, the current data does not suggest there are substantial differences in disease severity for XBB infections, it said. There is, however, early evidence pointing at a higher reinfection risk, as compared to other circulating Omicron sublineages. Cases of reinfection were primarily limited to those with initial infection in the pre-Omicron period.

BQ.1

BQ.1 is a sublineage of BA.5. It has a prevalence of 6% and it has been detected in 65 countries. The variant is showing a "significant growth advantage" over other circulating Omicron sublineages across Europe and the US, and therefore warrants close monitoring.

The WHO added, however, that at this time, there is no epidemiologic data to suggest an increase in disease severity. Protection by vaccines against infection may be reduced but no major impact on protection against severe disease is foreseen, it said.

The WHO panel ended with the conclusion that the treatment required for the subvariants XBB and BQ.1 does not differ from the treatment of Omicron. However, it requested countries to continue to be vigilant, to monitor and report sequences, as well as to conduct independent and comparative analyses of the different Omicron sublineages.

What about the BF.7 variant?

There has been an alarming surge in Covid cases in China, Japan, South Korea, France and the United States.

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