Office for National Statistics (ONS) data indicates that covid infections are continuing to rise across the UK.
However, officials say vaccines are stopping similar rises in hospital admissions, and they are encouraging everyone to come forward for both doses.
“It will help us to break the chain of transmission, and save lives,” said Dr Jenny Harries, from the UK Health Security Agency.
England is due to lift most remaining Covid restrictions on 19 July.
According to ONS estimated there was “a notable increase in infection rates” across England, Wales and Scotland during the week ending 26 June.
One in every 250 people may now be infected by coronavirus, it says.
In Scotland, which has not seen estimated level of infections this high since the start of February, one in every 150 people could be infected.
These cases are driven by the Delta variant and, although infection rates are now similar to February, it is hoped fewer people will go on to become ill with severe symptoms, because of the vaccination programme.
Recent government figures on confirmed cases suggest that vaccines have already reduced hospital admissions and deaths.
Fewer than one in 1,000 infections is now leading to a death – compared with one in 60 last winter.