Updated COVID vaccines are necessary, just as flu vaccines are updated because immunity wanes with time, even among those vaccinated and those that have had prior COVID infections. In addition, the virus mutates, which creates a need for vaccines that better match strains circulating in the general population.

Add Yahoo as a preferred source to see more of our stories on Google. A new Covid variant is spreading across the U.S. and it may be able to evade protection from current vaccines. The variant, known as BA.3.2, has been detected in nasal swabs taken from ...