LONDON, March 24 (Xinhua) -- It is wrong to assume that the virus will inevitably continue to become milder, a British scientist has said.

"There has been a view put out in the media that this is inevitable, that the direction of travel is inexorably towards mildness. That's complete rubbish," Simon Clarke, a microbiologist at the University of Reading, told Xinhua in an interview on Monday.

"It just happens to have happened that way with omicron. That doesn't mean it's going to be constantly heading in that direction. It could easily turn around," said the associate professor specializing in how humans interact with infectious diseases.

Clarke made the remarks after more than 500,000 new cases, mainly of the omicron variant, were reported in Britain last week.

Official figures on Tuesday showed Britain added 592,459 COVID-19 cases and 836 deaths over the last seven days, bringing the national counts to 20,413,731 and 163,929 respectively.

"The finding of over half a million cases, principally of omicron in the UK doesn't really surprise me," said Clarke.

Last month, British Prime Minister Boris Johnson announced the end of all domestic COVID-19 restrictions in England.

"What we've done here is to remove a lot of restrictions that were put in place to reduce the amount of interpersonal spread, interpersonal interactions and therefore viral spread. So if you remove those, you'll get more viral spread, and the numbers of infections will just go up and down," said Clarke.

Clarke said omicron was "not just a bit of a flu".

"I'm not sure people realise quite how devastating influenza, proper influenza, not just a bad cold, can actually be, but unfortunately in the UK and in other parts of the world, we've had a bunch of medics and scientists, a small minority, who have consistently sought to downplay the importance of this pandemic," he said.

In a separate report, the Office for National Statistics (ONS) said one-in-20 people in England had the virus in the week ending March 12. The ONS also reported increased cases in all age groups, with the number of over-70s infected reaching the highest ever level.

The British government announced second boosters are to be offered to 5 million people across England at higher risk from COVID in the coming weeks.

Clarke said it was quite likely, particularly in elderly and vulnerable groups, for repeated cycles of vaccination to be given over the coming years because the effectiveness wears off.

A further jab, which would be the fifth for most people, may also be needed this fall, he said.

On the evolution of the virus, Clarke predicted that a "more aggressive version" is a "distinct possibility".

"We will not know whether a new, more aggressive variant is likely, or going to happen until it actually does. There is no scientific logic for assuming that it will be less serious, apart from people who want it to decrease, or deny the significance of the infection," he said.

Given "different variations of this virus on the way", Clarke expected the virus "to become more and more transmissible", or otherwise "it won't out-compete the versions that are already established."

Deeming precautions necessary, Clarke said, "I have a mask in my jacket pocket, and I would put it on if I was in a particularly crowded space."