7 March 2022. The BA.2 sub variant of the COVID-19 Omicron variant is spreading rapidly across Thailand and is replacing the BA.1 as the dominant sub variant. Medicine which is effective against the Delta variant and BA.1 is not as effective against the BA.2https://www.thaipbsworld.com/ba-2-sub-variant-of-omicron-becoming-dominant-strain-in-thailand/