Covid positive tests among hospital patients have the highest level in ten months, new figures show.
The proportion of hospital patients in England with respiratory symptoms testing positive for the virus reached 9.3 per cent on Friday 29 August - the highest hospital 'positivity rate' since 30 October and 55 per cent higher than it was a month earlier, according to data from the UK Health Security Agency (UKHSA).
Experts stress that this rate is much higher than for the population as a whole and they point out that it is a different measure to the 'hospitalisation' figure, which shows how many people have been admitted to hospital because of Covid (meaning their case is serious).
Encouragingly, that level that has stayed relatively low and fairly flat for many months now.
But the level of the virus among those hospital patients who were admitted for reasons other than Covid - but do have it (although typically in a much milder form) - has proved to be a good indicator of wider trends across the UK.
And it is the best indicator we have at this time of the year when there is no population-wide surveillance of the virus.
The positivity rate in England rose from 6.0 per cent on 28 July to 9.3 per cent on 29 August, a 55 per cent increase.
It was last higher on 30 October, when it was 9.6 per cent - although it remains well below the peaks of last year's waves - of 16.5 per cent in July and 14.7 per cent in mid October.
But with children and students returning to education and the cooling weather pushing people into - often poorly ventilated - rooms more often, the concern is that cases will continue to rise.
At the same time, immunity given by vaccines and previous infections has waned and highly contagious new Covid variant XFG, or Stratus, is now the dominant variant in the UK.
"It's not surprising that Covid positivity rates are at a 10 month high and they are likely to increase further," Professor Lawrence Young, a virologist at Warwick University, told The i Paper.
"A combination of return to work and school after the summer holidays, cooler weather and waning immunity will contribute to increased spread of the virus.
"These factors are further exacerbated by the continued development of new virus variants and by access to the free autumn/winter vaccine booster being restricted to those aged 75 and over along with those who are the most clinically vulnerable," he added.
Nearly 13 million fewer people will be offered an autumn booster for Covid this year.
The Government said that pensioners aged 65 to 74 will no longer be able to go for a free jab.
Meanwhile, 6.9 million people in "clinical risk" groups such as pregnant women and people with chronic heart and liver disease will also be excluded for the first time.
Simon Williams, a behavioural scientist and public health expert told The i Paper: "Most people haven't been boosted for years - and we know that this will be more of an issue now that the UK is reducing boosters this Autumn, which I think is a bad call.
"Vaccines are not just about keeping people out of hospital but also about keeping people healthy in general and avoiding sickness," he said.
The government's decision to offer fewer Autumn boosters this year is based on expert advice from the Joint Committee on Vaccination and Immunisation (JCVI) which continuously monitors and evaluates emerging scientific evidence on Covid vaccines, although many scientists don't agree.