Covid cases and hospitalisations are rising in England – and experts don’t know why.
The lifting of all Covid restrictions has made it more difficult to properly track and understand the country’s epidemic, scientists have warned the government following a recent and sudden rise in hospital admissions.
Since the turn of the month, infections and hospitalisations have both increased across England, according to the latest data.
It comes after the scaling back of testing and removal of mandated self-isolation at the end of February, as part of plans for “living with Covid”.
The uncertainty surrounding the current prevalence of cases has been reflected in the fact that admissions appeared to initially rise before infections, when typically it is the former that follows the latter by seven to 10 days.
Figures recently published by the React and ZOE Covid studies have since confirmed the current scale of infections, with cases rising in all age groups and regions of the country, but experts fear it is becoming increasingly harder to monitor and explain fluctuating trends in England’s epidemic.
“The one thing we do know is that both cases and admissions are rising, seemingly across all age groups and regions. What we don’t understand is exactly why,” said Christina Pagel, a professor of operational research at University College London (UCL).
According to the ZOE Covid study, around 175,100 new infections are occurring on a daily basis in the UK – an increase of 20 per cent from 145,530 reported last week. The government’s Covid dashboard shows 71, 259 cases were picked up on Thursday.
The latest surveillance report from the UK Health Security Agency (UKHSA) meanwhile says that infections increased nationally between 28 February and 6 March.
Case rates were highest in those aged 30 to 39, with a weekly rate of 542.7 per 100,000 population. The hospital admission rate for England also rose, from 9.84 per 100,000 in the previous week, to 11.26.
These trends could be driven by a number of different factors, scientists say, including the waning of protection provided by boosters, the emergence of the highly infectious Omicron sub-variant, known as BA.2, increased social mixing between the young and old, a reduction in mask-wearing and testing, and the removal of self-isolation requirements.
Prof Pagel said the lack of clarity around England’s epidemic “highlights the importance for continued surveillance such as the Office for National Statistics’ (ONS) infection survey and the React study, but also the limitations of scaling back testing and telling the public that it is no longer necessary, because we just don’t have good real-time information about spread.”
The ONS’ national Covid survey is set to be wound down later this year, while Professor Tim Spector, head of the ZOE Covid study, said on Thursday that funding for the programme had not been renewed by the UKHSA.
Professor Irene Petersen, an epidemiologist at UCL, said that scientists had been caught off-guard by the recent rise in hospital admissions.
“As close contacts are no longer encouraged to test it is likely that there are fewer people who realise that they are infectious and therefore not testing,” she said.
She also speculated that “one of the reasons why we see an increase in hospitalisations now is not so much because of the waning in the triple vaccinated, but in the double vaccinated”. Some 33 per cent of all people aged over 12 have yet to receive a third dose, government data show.
Paul Hunter, a professor in medicine at the University of East Anglia, also tweeted that the recent increase in hospital admissions had “taken me by surprise”.
However, experts have said that, for now, the rise in hospitalisations is being driven by Covid-positive people who are seeking care for a separate health issue. The number of patients being admitted because of Covid continues to lag behind, data show.
On 1 March, 4,452 people were in hospital with Covid, compared to 3,525 people who were being treated for the disease. By 8 March, this had risen to 4,908 and 3,661 respectively.
“Whether it’s just a short-lived bump or a bigger mini-wave is very much up in the air I’d say,” said Colin Angus, a senior research fellow and health inequalities modeller at the University of Sheffield.
He said the rise in people in hospital, both with and because of Covid, “points to a genuine increase in Covid prevalence in recent weeks”.
Prof Petersen said “we may not need to worry too much,” adding that it would be troubling if the number of people admitted to intensive care units “goes up dramatically”. She said a rise is expected, but the “key is that they are not overloaded”.
However, Saffron Cordery, the deputy chief executive of NHS Providers, warned that the NHS remains “under intense pressure, despite moving towards spring, when we normally expect to see seasonal winter pressures ease.”
She added: “It remains deeply concerning that 6.1 million people are on waiting lists for routine care, with significant backlogs across mental health and community services as well.”
Ms Cordery said continuing staff shortages and the increase in Covid hospitals, after weeks of falling admissions, was a “real concern”.
“The NHS now has 110,00 staff vacancies, and these gaps are putting significant pressure on quality of care and patient safety,” she said.
