World Health Organization provides clarity on evolution of Covid-19 virus

Echoing his thoughts, Stuart Campbell Ray, an infectious disease expert at Johns Hopkins University said: “It’s the longer, persistent infections that seem to be the most likely breeding grounds for new variants.”

“It’s only when you have a very widespread infection that you are going to provide the opportunity for that to occur,” he added.

Because Omicron appears to cause less severe disease than delta, its behaviour has kindled hope that it could be the start of a trend that eventually makes the virus milder like a common cold.

It’s a possibility, experts say, given that viruses do not spread well if they kill their hosts very quickly. But viruses do not always get less deadly over time.

A variant could also achieve its main goal – replicating – if infected people developed mild symptoms initially, spread the virus by interacting with others, then got very sick later, Ray explained by way of example.

“People have wondered whether the virus will evolve to mildness. But there’s no particular reason for it to do so,” he said. “I don’t think we can be confident that the virus will become less lethal over time.”

Getting progressively better at evading immunity helps a virus to survive over the long term. When SARS-CoV-2 first struck, no one was immune. But infections and vaccines have conferred at least some immunity to much of the world, so the virus must adapt.

It is because of this, that experts have urged wider vaccination now, while the existing shots still work.