Covid-19 levels are following an “uncertain” trend in much of the UK, with only Scotland seeing a clear increase, figures show.

Total infections for the whole of the UK are up for the fifth week in a row, but there is fresh evidence the current rise is slowing down.

Levels continue to vary across different regions and age groups in England, though rates have jumped among over-70s.

An estimated 1.6 million people in private households in the UK were likely to have Covid-19 in the week ending February 28, up 3% from 1.5 million the previous week, according to the Office for National Statistics (ONS).

This is the smallest week-on-week percentage increase since the latest rise in infections began at the end of January.

If the spread of the virus is slowing down, it could mean infections will peak at around half the level reached during the Christmas 2022 wave, when the total climbed to just under three million.

The current increase is being driven by the Omicron variant BA.2.75, which now accounts for more than eight in 10 (85.8%) sequenced infections in the UK.

Michelle Bowen, ONS head of health surveillance, said the new figures pointed to an “uncertain picture across much of the UK”, with only Scotland showing a clear increase in the number of people testing positive for Covid-19.

“Infections continue to vary across regions and age groups in England. Though many age groups have uncertain trends, rates are increasing in the over-70s,” she added.

Covid-19 is least prevalent in Northern Ireland, where one in 75 people is estimated to have the virus.

The estimate for Wales is one in 45, while for England and Scotland it is one in 40.

Some 128,400 people in Scotland were likely to test positive for coronavirus in the latest week, up from 117,100 the previous week and the highest number since the start of the year.

Around 2.8% of over-70s in England are estimated to have the virus, up week-on-week from 2.4% and the highest percentage of any age group.

Among children in school years 7 to 11, the rate has dropped from 2.2% to 1.5%.

At a regional level, the percentage testing positive has increased in the North East and West Midlands, with the trend uncertain elsewhere.

The ONS infection survey is the most reliable measure of the prevalence of Covid-19 and is based on a sample of swab tests from households across the country.

However, the survey will come to a halt at the end of this month.

Data collection will be “paused” from March 31 with any new surveys announced “in due course”, the UK Health Security Agency (UKHSA) said on Thursday.

The decision brings to an end a survey that has run continuously for nearly three years and which has been recognised worldwide as the “gold standard” for measuring levels of coronavirus among the population.

Besides providing vital data on the scale and duration of each wave of the virus, the survey has supplied crucial information on the emergence of new variants, antibody levels and long Covid.

Professor Steven Riley, UKHSA director general of data, acknowledged the survey has been an “important tool” in helping understand coronavirus, adding: “We will continue to ensure our surveillance activities remain proportionate and cost-effective with the move to living with Covid-19.

“We remain committed to monitoring the threat posed by Covid-19 through our range of surveillance systems and genomics capabilities, which report on infection rates, hospitalisations and the risks posed by new variants.”

The infection survey has been delivered by the ONS in partnership with the University of Oxford, University of Manchester, the UKHSA and the Wellcome Trust.

Separate UKHSA figures show the rate of hospital admissions in England for people with Covid-19 has risen slightly, standing at 9.4 per 100,000 last week, up from 9.0 the previous week.

The rate reached 11.8 per 100,000 during the wave of infections over Christmas.

A total of 7,655 people were in hospital in England on March 8 who had tested positive for coronavirus, up 2% from 7,507 a week earlier.

Patient numbers reached 9,535 at the peak of the Christmas wave, though this was well below levels seen during early waves of the virus.