Virus expert voices concern about new XBB, BQ.1.1 subvariants mixing

Dr Anan Jongkaewwattana posted on Facebook that XBB and BQ.1.1 are likely to replace BA.5, which is currently a dominant subvariant, for the upcoming winter/cold season.

XBB was recently discovered in Asia, while BQ.1.1 has mostly been reported in Europe and the Americas.

“These two subvariants have mutations at similar positions on their spikes, which enable them to evade immunity created by Covid-19 vaccines or in patients who have recovered from previous infections,” said Anan, who is a director of the Veterinary Health Innovation and Management Research Group Unit, National Centre for Genetic Engineering and Biotechnology.

Anan said XBB has “more mutating positions” than BQ.1.1, making it more efficient in evading immunity and infecting human cells. Meanwhile, BQ.1.1 has a mutation in position L452R that XBB does not have, which helps it infect the ACE2 receptor, a protein on the surface of many human cell types.

“If these two mix together, they could create a new subvariant that has both advantages, resulting in a more infectious version of Covid-19,” Anan warned.

Thailand reported its first XBB case is a 48-year-old Thai woman who developed a cough and blocked nose before visiting hospital on September 27. She tested positive for Covid but did not develop fever and recovered on October 6 after two weeks of home isolation.

The second case was a 60-year-old foreign woman who developed a cough and tested positive with an ATK kit on September 27, a day before visiting hospital.

The Medical Sciences Department said on Monday there was no need to panic since the XBB strain, like other Omicron subvariants, is a weak version of the virus.

The BQ.1.1 subvariant, meanwhile, has not spread in Thailand yet, according to the Department of Disease Control.

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BQ.1.1, XBB variants have not spread in Thailand yet: Disease Control Dept