BA.2.75 was found in 75.4% of new domestic infections, rising from 60.1% in the previous week, when it overtook BA.5 as the dominant subvariant, said DMS director-general Dr Supakit Sirilak.
Genome sequencing on samples from new cases in Thailand last week found that 856 were caused by the BA.2.75 strain.
The XBB strain spreading in Singapore was found in 30 samples, while the BQ.1 subvariant affecting the Americas and Europe accounted for 13 cases sampled. The DMS found only one case of XBC or Deltacron, a hybrid of Delta and Omicron found recently in the Philippines.
Supakit warned that those who had recovered from infections by previous strains could be reinfected by the newly dominant BA.2.75. However, there is no evidence it causes more severe symptoms than other strains, he added.
“People are still advised to wear face masks in public, wash their hands regularly and get a vaccine booster shot every four months to stay safe from Covid-19,” he said. “Current vaccines are still effective and can reduce the chance of infection and prevent severe symptoms.”