World faces around 4,000 Covid-19 variants as researchers explore mixed vaccine shots

The world faces around 4,000 variants of the virus that causes Covid-19, prompting a race to improve vaccines, Britain said on Thursday, as researchers began to explore mixing doses of the Pfizer and AstraZeneca shots.

from UK News Headlines, Latest UK News and Live Updates - Times of India https://ift.tt/2MUnPLE