Vismita Gupta-Smith We're hearing about variants of the SARS-CoV-2 virus that causes COVID-19. How concerned should we be? And do vaccines provide protection against these variants? Welcome to Science in 5. I'm Vismita Gupta-Smith and this is WHO’s conversations in science. Answering these questions today will be WHO’s chief scientist, dr Soumya Swaminathan. Welcome, Soumya. Dr Soumya Swaminathan Hello Vismita, nice to be back with you again on Science in 5. Vismita Gupta-Smith Soumya, tell us what we know about these variants. How concerned should we be? And is it unusual for viruses to change? Dr Soumya Swaminathan From the beginning of the year, we've been tracking this virus and we know that it's gone through a lot of changes and there've been variants before. Now this particular time there have been two particular variants that have been reported to WHO. One was identified in the UK and one was identified in South Africa. They do have one change in common, we call it the N501Y mutation. But otherwise the two are different. And the reason there's concern is that both of these variants were associated with an increase in the number of cases in both of these countries. And scientists have now studied this and have found that these variants do tend to spread faster, they're more transmissible or more infectious. So that's the worrying part. However, so far, they do not seem to cause more severe illness or a higher death rate or any sort of different clinical manifestations. They seem to behave pretty much as the previous viruses were behaving and cause a pretty similar kind of disease.