The Centre for Medical Genomics, at Ramathibodi Hospital, has found the first case in Thailand of a descendant of the COVID-19 Omicron BA.5 sub-variant, called BQ.1.

The centre said, in its Facebook post today (Tuesday), that the US Centres for Disease Control and Prevention has issued a warning about the spread of BQ.1 and BQ.1.1, two descendants of Omicron’s BA.5 sub-variant.

They are described by Dr. Anthony Fauci, director of the US National Institute of Allergy and Infectious Diseases, as “pretty troublesome”, because of they possess dangerous qualities or characteristics that could evade some of the interventions available.

The two sub-lineages are responsible for more than 10% of all the current US cases, according to the latest Centres for Disease Control and Prevention data. There is no guarantee that the two strains will eventually overtake BA.5 as the dominant variant in the country, according to Dr. Fauci, adding that, if they do spread rapidly, they could threaten to reverse a nationwide decline in COVID cases.

BQ.1 and BQ.1.1 are reported to be resistant to current antibody medications used to treat COVID patients, such as Evusheld and Bebtelovimab, said the Centre for Medical Genomics.

BQ.1 is capable of evading antibodies from a COVID-19 infection or those generated by vaccination. Those inoculated with vaccines against the BA.5 sub-variant may, however, have a slightly higher level of antibodies against BQ.1, because it is a descendent of BA.5, said the centre.

The second generation of vaccines may, therefore, generate more antibodies against the increase of virus load from the BQ.1 and BQ.1.1 sub-variants, and a second generation of medication cocktails may be necessary to deal with these two sub-variants.

BQ.1 spreads 15% faster than BA.5.2 and 14% faster than BA.2 on daily basis. So, it is possible that BQ.1 could replace BA.5 as the dominant strain at the end of this year or next year, according to the Centre for Medical Genomics.