Covid infections continue to rise across the UK, driven by the Omicron BA.4 and BA.5 subvariants of the virus.

New figures from the Office for National Statistics (ONS) show that 2.7 million people in private households are estimated to have had Covid-19 last week, up 18% from 2.3 million the previous week.

Mark Woolhouse, professor of infectious disease epidemiology at the University of Edinburgh, said the UK was now in “a substantial wave of infection” which underlines that coronavirus “is not just a problem in winter”.

An immunologist warns that a new strain of Covid could be causing new symptoms on those infected, particularly at night, the Independent reports.

Professor Luke O’Neill from Trinity College Dublin told a Irish radio: “One extra symptom from BA.5 I saw this morning is night sweats.”

“The disease is slightly different because the virus has changed,”  O’Neill warned.

He added: “There is some immunity to it - obviously with the T-cells and so on - and that mix of your immune system and the virus being slightly different might give rise to a slightly different diease, strangely enough night sweats being a feature.

“But very importantly, if you are vaccinated and you’re boosted, it doesn’t progress into severe disease is the message to keep reminding people.”