All viruses mutate — including the novel coronavirus. But as the world now races to develop a Covid-19 vaccine, the coronavirus mutations are not expected to alter vaccine efficacy during this race, said World Health Organization chief scientist Dr. Soumya Swaminathan.

“The mutations have not been shown to be in those regions of the virus — the spike protein, the receptor binding domain — that are going to alter the efficacy of a vaccine so far,” Swaminathan said on Friday during a live Q&A broadcast on WHO’s social media pages.

Swaminathan added that “viruses keep on changing and we have to keep an eye on that.”

Currently there are about 200 vaccine candidates in development around the world, with 10 in human trials — four in the United States, five in China and one in the United Kingdom — and 126 in preclinical trials globally, according to WHO.

Regarding how the coronavirus may differ across countries due to mutations, “the virus may be slightly different but it’s not so different that the vaccine will not work,” Swaminathan said.

“It’s also good to have vaccine trials in many different countries because you have different populations, different genetics, different risk factors and WHO very much would like to see the candidates that are being developed now being tested in many countries.”