The number of people in the UK with COVID has risen by 32% to almost 2.3 million, latest figures show.
It is up from 1.7 million people the previous week and the highest estimate for total infections since late April.
But it is still below the record high of 4.9 million which was reached at the end of March.
Omicron variants BA.4 and BA.5 are likely behind the latest surge, the Office for National Statistics said.
They are thought to be the most dominant strains in the UK.
The virus continues to be most prevalent in Scotland, where 288,200 people were likely to test positive for COVID last week, or one in 18.
This is up week on week from 250,700, or one in 20.
In England, more than 1.8 million people were likely to have had the virus last week, the equivalent of around one in 30.
This is up from 1.4 million, or one in 40 people, the previous week.
Wales has seen infections rise sharply to 106,500 people, or one in 30, up from 68,500, or on in 45.
In Northern Ireland, infections rose to an estimated 71,000 people, or one in 25, up from 59,900, or one in 30.
Sarah Crofts, ONS head of analytical outputs for the COVID-19 infection survey, said: “Across the UK we’ve seen a continued increase of over half a million infections, likely caused by the growth of BA.4 and BA.5 variants.
“This rise is seen across all ages, countries and regions of England.
“We will continue to monitor the data closely to see if this growth continues in the coming weeks.”