The BA.2 subvariant of Omicron is not just more transmissible than the original strain, BA.1, but may also cause more severe disease, suggests a lab study done in Japan.

Investigators infected hamsters with BA.1 and BA.2 strains and noted that the hamsters infected with BA.2 got sicker, had more lung damage and loss of body weight. Results appeared to be similar when mice were infected with the two strains. The study revealed that BA.1 and BA.2 both seem to evade immunity induced by COVID-19 vaccines. The monoclonal antibodies used to treat COVID-19 patients did not appear to have much impact on BA.2.

The investigators proposed that BA.2 must be recognized as a unique variant of concern and should be closely monitored. The study, yet to be peer-reviewed, is published on the preprint server bioRxiv… (Medscape)