Covid-19 infections have fallen slightly in England and Wales, but the trend is uncertain in Scotland and Northern Ireland, figures suggest.
There is still a high prevalence of the virus across the country, with infections remaining above pre-Christmas levels.
Numbers are down overall for the UK, however.
Around one in 20 people in private households in England had Covid-19 in the week to February 12, or 2.4 million people – down from one in 19, or 2.8 million people, in the week to February 5.
Wales also saw a decrease week-on-week, from around 121,200 people to 112,600, though the proportion remained unchanged at one in 25.
Scotland and Northern Ireland are estimated to have seen a small rise in infections, though the ONS described the trend in the two nations as “uncertain”.
In Scotland, around 219,300 people were likely to have had Covid-19 last week, up from 211,300 the previous week – both the equivalent of around one in 25.
Northern Ireland saw infections remain broadly level, at an estimated 146,600 people or one in 13, compared with 145,600 people – also one in 13 – the previous week.
Across the UK as a whole, 2.9 million people were estimated to have Covid-19 in the seven days to February 12, down week-on-week from 3.3 million.
The number stood at 4.3 million at the start of the year.
The ONS infection survey is the most reliable measure of the prevalence of coronavirus in the UK.
It is based on a representative sample of swab tests collected from tens of thousands of households, and is therefore able to estimate the percentage of people likely to test positive for Covid-19 at any one point in time – regardless of when they caught the virus, how many times they have had it and whether they have symptoms.
By contrast, the number of cases of Covid-19 announced each day by the Government is limited only to those people who have reported themselves as testing positive for the virus, and is being increasingly affected by how many people are coming forward for tests or who are taking a test because they know they have coronavirus symptoms.
When estimating infections among age groups in England, the ONS found that around one in 13 children (7.6%) from age two to school year 6 are likely to have had Covid-19 last week, the highest level for any age group.
This is down from one in nine, or 11.5%, the previous week.
For children in school years 7 to 11 the estimate was around one in 16 (6.3%), down week-on-week from one in 11 (8.7%).
