Omicron ‘stealth’ COVID variant now dominant globally

March 29 (Reuters) -  A sub-variant of the highly transmissible Omicron version of coronavirus known as BA.2 is now dominant worldwide, prompting surges in many countries in Europe and Asia and raising concern over the potential for a new wave in the United States.  

BA.2 now represents nearly 86% of all sequenced cases, according to the World Health Organization. It is even more transmissible than its highly contagious Omicron siblings, BA.1 and BA.1.1, however the evidence so far suggests that it is no more likely to cause severe disease.  

As with the other variants in the Omicron family, vaccines are less effective against BA.2 than against previous variants like Alpha or the original strain of coronavirus, and protection declines over time. However, according to UK Health Security Agency data, protection is restored by a booster jab, particularly for preventing hospitalisation and death.