The latest estimates from the Office for National Statistics (ONS) suggest one in 37 people in the UK has coronavirus, a rise from one in 50 the week before.
Experts warn of a “notable rise” in older people in England and Wales.
They say vaccines are the best defence against the virus and urge people aged 50 and over and others eligible for booster jabs to get them.
There are fears of a flu and Covid “twindemic” this winter.
Sarah Crofts, deputy director for the ONS Covid survey, said there was a need for close monitoring as we moved through colder months.
She added: “Infections have risen again across much of the United Kingdom, continuing the pattern of steady increases seen over recent weeks, although Scotland and the North East of England had uncertain trends in the latest week.”
