COVID-19 crisis could return quickly as infections surge, UK adviser warns

British Prime Minister Boris Johnson is removing most pandemic restrictions in England from July 19, saying a rapid rollout of COVID-19 vaccines has largely broken the link between infections and serious illness or death.

Some scientists are worried, though. Daily reported cases are at their highest since January, while the reproduction "R" number remains above one, indicating a continued exponential growth of cases.

"We are not by any means out of the woods yet on this," Chief Medical Officer Chris Whitty said late on Thursday during a webinar hosted by the Science Museum.

He added that the doubling time for hospitalisations was around three weeks, and that low numbers of people in hospital currently could escalate in next couple of months.

"It doesn't take many doublings until we're in actually quite scary numbers again ... I don't think we should underestimate the fact that we could get into trouble again surprisingly fast," Whitty said.

The Office for National Statistics estimated as many as 1 in 95 people in England were infected with COVID-19 in the week to July 10, the highest prevalence since February.

"New cases of Delta will lead to long COVID, hospital admissions and deaths," said James Naismith, Director of the Rosalind Franklin Institute

"The ratios between these have been massively changed by the safe and effective vaccines we are administering but the link is not eliminated."

Britain's COVID-19 death toll is among the highest in the world but two-thirds of its adult population have been fully vaccinated.

On Monday, the last remaining businesses still closed in England, including nightclubs, can finally reopen, but business leaders have warned that the self-isolation requirement for people exposed to positive cases could hinder the economy.

Over 520,000 contact tracing alerts were sent through the National Health Service app in the week to July 7.

"The hospitality sector, 20% of staff are isolating, the health service up to 25% of staff are absent, and buses and trains delayed," Karan Bilimoria, president of the Confederation of British Industry (CBI), told LBC radio.

"This cannot go on ... This is wrecking the economy."