The WHO says the new Covid strain in the UK appears to be more contagious

World Health Organization officials said Monday that the coronavirus is mutating “at a much slower rate” than seasonal flu, even as officials in the UK announced this weekend that a new mutation of the virus is making it easier to spread.

Seasonal flu mutates so often that scientists regularly have to develop new vaccines to inoculate the population against the virus every year. British officials have told the WHO that the Covid-19 vaccines appear to be just as effective against the new strain, but more research is needed. While all viruses mutate naturally, not every mutation makes a virus more contagious or virulent.

“SARS-CoV-2 mutates much more slowly than influenza,” Soumya Swaminathan, WHO chief scientist, said at a news conference. “And so far, although we have seen a number of changes and a number of mutations, none have had a significant impact on the susceptibility of the virus to the currently used therapies, drugs or vaccines under development, and it is hoped that will remain so. “

WHO officials reiterated that UK officials have said the new variant could be up to 70% more transmissible than the original strain of the virus. Dr. Mike Ryan, executive director of the WHO health emergency program, said it was unclear whether the increase in spread in the UK is due to the mutation or to human behavior.

“We’ve seen an estimate of a small increase in UK reproductive numbers,” he said, meaning the virus is spreading more quickly, which could mean it is more contagious or spreads more easily in colder months. It can also mean that people are getting lax about following public health protocols. “It remains to be seen how much of that is due to the specific genetic change in the new variety. I suspect a few.”

Maria Van Kerkhove, head of WHO’s emerging diseases and zoonosis division, said British officials estimate the mutation increased the virus’s reproductive rate from 1.1 to 1.5. That means that each person infected with the variant is estimated to infect an additional 1.5 people, an increase of 1.1 when infected with the original variant.

She added that officials are examining three elements of the new variant. She said scientists are looking into whether it spreads more easily, whether it causes more or less serious disease, and how the antibody responds to an infection. Van Kerkhove and others emphasized that there appears to be no effect on the effectiveness of the Covid vaccines on the new variant.