Covid-19 infections have fallen simultaneously in all four UK nations for the first time since the middle of January, figures show.

Wales has seen infections drop for the first time in seven weeks, while in Northern Ireland prevalence of the virus has declined to levels last seen before Christmas 2021.

England and Scotland have also recorded falls, suggesting the recent surge in infections driven by the Omicron BA.2 variant has peaked.

The virus is still circulating at high levels in much of the country, however.

Across the UK, 3.8 million people in private households are estimated to have had Covid-19 in the week to April 16, down from 4.4 million the previous week.

Total infections in the UK hit a weekly record of 4.9 million in late March.

In England, infections have dropped for the second week running, with 3.2 million people likely to test positive for Covid-19, or one in 17 – down from 3.8 million, or one in 14.

Wales has recorded its first week-on-week fall in nearly two months, with 198,400 people estimated to have coronavirus, or one in 15 – down from 231,900, or one in 13.

Infections in Northern Ireland are dropping quickly and have returned to levels last seen in mid-December, with 65,300 people likely to have had Covid-19 last week, or one in 30 – down sharply from 95,900 people, or one in 19.

Levels are not falling quite so steeply in Scotland but infections have now declined for four weeks in row, with 281,400 people estimated to have had the virus last week, or around one in 19.

This is down from 314,800 people, or one in 17, the previous week.

Professor James Naismith of the University of Oxford said the figures showed that prevalence of the virus “peaked around the middle of March” and that “all things being equal, a fall in prevalence should feed through to reduced pressure in hospitals which are clearly under extreme stress.”

He added: “This will lead to a fall in deaths, which have continued to rob families of their loved ones.”

The last time all four UK nations were estimated to have recorded a simultaneous week-on-week fall in infections was in the seven days to January 22.

The percentage of people testing positive for Covid-19 in England decreased in all age groups in the most recent week, the ONS said.

Infections have also fallen in all regions except the North East, where the trend is described as “uncertain”.

The figures come as the number of people in hospital with Covid-19 in the UK shows early signs of being on a downwards trend, having peaked at around the same level that was reached during the first Omicron surge in January.

Deaths involving Covid-19 are continuing to rise slowly, but remain well below the numbers seen during the first and second waves of the virus.

The ONS infection survey is the most reliable measure of the prevalence of Covid-19 in the UK.

It uses a sample of swab tests collected regularly from tens of thousands of households, and is therefore able to estimate the percentage of people likely to test positive for coronavirus at any point in time, regardless of when they caught the virus, how many times they have had it and whether they have symptoms.

The survey is more representative of the level of Covid in the UK than the number of cases announced each day by the Government, which includes only those who have reported themselves as testing positive, so it is affected by how many people are able to take a test or know they have symptoms.

The latest ONS data suggests just one in eight people newly infected with Covid-19 is currently being included in the Government total.

Separate figures published by the ONS on Friday show that around seven in 10 people in England are likely to have had coronavirus since the early months of the pandemic.

An estimated 38.5 million people in private households – or 70.7% of the population – have had at least one infection since the end of April 2020.

The figures run up to February 11 2022, so do not include people who have been infected for the first time in recent weeks.

They are based on the infection survey that began in England on April 27 2020, which also means they do not cover most of the initial wave of the virus that began in early March.

But it is the first time an attempt has been made to calculate the cumulative number of people who have had Covid-19 over much of the pandemic.