Stealth Omicron BA.2 spread faster than BA.1 but there's a catch: UK study. Read here
After two doses, vaccine effectiveness was 9% and 13% respectively for BA.1 and BA.2, after 25 weeks
This increased to 63% for BA.1 and 70% for BA.2 at 2 weeks following a third vaccine
In some positive news regarding stealth Omicron, a recent study has revealed even though BA.2 sub-lineage of the COVID variant spreads much faster than the BA.1 strain, it seems to show higher vaccine protection.