The U.K. Coronavirus variant: Some facts

When researchers took a close look at its genome, they were struck by the relatively large number of mutations — 23, all told — that it had acquired. Most mutations that arise in the coronavirus are either harmful to the virus or have no effect one way or another. But a number of the mutations in B.1.1.7 looked as if they could potentially affect how the virus spread.

The variantappears to be morecontageous.In preliminary work, researchers in the U.K. have found that the virus is spreading quickly in parts of southern England, displacing a crowded field of other variants that have been circulating for months.

Some scientists have raised the possibility that the increase in transmission is at least partly the result of how it infects children. Normally, children are less likely than teenagers or adults to get infected or pass on the virus. But the new strain may make children “as equally susceptible as adults,” said Wendy Barclay, government adviser and virologist at Imperial College London.

There is no strong evidence that it causes more severe disease.But there is reason to take the possibility seriously.

The variant may not as such render the new vaccines ineffective according to most of the experts.But Kristian Andersen, a virus expert at Scripps Research Institute, thinks it is too early to dismiss the risk to vaccines. If the U.K. variant evolved to evade the immune system in immunocompromised patients, those adaptations might help it avoid vaccines. The vaccines would not become useless, but they would become less effective. Fortunately, experiments are underway to test that possibility.