Since December 22, people in England who have tested positive for Covid have been allowed to end isolation if they have negative lateral flow tests on days six and day seven.

Fully vaccinated close contacts of someone who has tested positive also no longer need to self-isolate, but those who are not vaccinated have to isolate for 10 days.

On Monday, the Centers for Disease Control and Prevention (CDC), said it was important to follow the science, but it was also important to keep society functioning.

“The change is motivated by science demonstrating that the majority of SARS-CoV-2 transmission occurs early in the course of illness, generally in the 1-2 days prior to onset of symptoms and the 2-3 days after,” the CDC said.

The agency said that infected persons and those exposed to them should observe “strict mask use” for five days after their isolation or quarantine ends. Symptomatic cases will still need to isolate for the full 10 days.

Experts said that the infectious period for omicron appeared to be shorter than delta meaning a longer self isolation period was not needed.

Sir John Bell, Regius professor of Medicine at the University of Oxford, said that he would support a move to five days if there was science to support the move.

“That’s one way to deal with the quarantine issue,” he told Radio 4’s Today Programme.

“My view is that natural flow tests are quite a good way of marking infectiousness and you could have sequential lateral flow tests.

“That is, in my view, a much better way to measure and quantitate whether we’re allowing people to go back into the community who are infectious.”

The self-isolation period for those who test positive remains 10 days for people living in Scotland, Wales and Northern Ireland.