Scientists believe it is only a matter of time before a new wave of Covid will cause cases to rise.
There has been a rise in Covid hospitalisations in the past week, according to official figures, as a wider winter crisis grips the NHS.
But Covid cases in the general population are at their lowest level for more than two years – hovering around the same point for the last month.
Scientists caution people not to become complacent as we could see a fresh wave of cases in the coming months.
Steve Griffin, a virology professor at the University of Leeds, said: “We will continue to see multiple waves each year for the foreseeable future. I would expect the next wave to be in spring – but that’s a guess.”
How big the next Covid wave will be remains uncertain and depends on immunity, vaccinations and the risk of a new variant, scientists say.
Paul Hunter, a professor of medicine at the University of East Anglia, explained: “At some point I would expect infections to start rising again but whether that will be this month, next month or later is not clear to me. I would be surprised not to see cases rising before Easter – but I have often been surprised by Covid.”
And Sheena Cruickshank, immunologist and professor in biomedical sciences at Manchester University, said: “I don’t see that Covid will go away soon as it continues to evolve.”
The latest Covid figures, published by the UK Health Security Agency (UKHSA) on Thursday, suggest cases may already be starting to pick up – although scientists caution that it is difficult to read too much into figures relating to the Christmas period.
This is because people are less likely to visit their GP, while disease surveillance systems have less reliable data to go on.
The UKHSA said that hospital admissions for people with Covid increased by about 5 per cent in the week to Sunday, 5 January, from 1.32 per 100,000 of the population to 1.39.
Over the same period, the proportion of people with symptoms testing positive for Covid in the national laboratory reporting system rose slightly from 1.8 per cent to 2.1 per cent in England.
Although this suggests a slight increase, this is much lower than the so-called positivity rate for flu, which stood at 21.8 per cent at the same point.
Because people are being tested in hospital with symptoms, these positivity rates are much higher than for the general population.
But scientists say they do give a good indication of wider trends across the UK – even if changes around Christmas mean the figures need to be treated with an extra degree of caution.
So with Covid rates so much lower than they have been for some time, why are scientists so sure it will be back?
Vaccination levels
Scientists are concerned by NHS figures showing that the number of people taking up the offer of a free vaccine in in the latest autumn booster campaign is considerably lower than at the same point last year.
“Low vaccine uptake is a real concern, particularly among people under 65 and in a clinical risk group,” Virologist Lawrence Young, a professor at Warwick University, said.
Just 59.1 per cent of all over 65s were vaccinated in the latest autumn booster campaign in England, compared to 70.2 per cent the year before, according to NHS figures – a 16 per cent drop.
And only 23.5 per cent of those under 65 years old and with weakened immune systems have had a vaccine.
Overall, 9.4 million Covid jabs have been given so far in the autumn booster campaign, compared to 11.8 million last year, according to analysis by Bob Hawkins, a data scientist who works with Independent Sage.
The booster campaign still has nearly three weeks to run but the gap is not expected to close much over that time, given that only about 15,000 injections have been given in the past two weeks.
Waning immunity from prior infection
Along with vaccines, immunity built up from previous infections is also a good way to protect against further Covid infections.
But the low level of cases seen in the past two months means that the nation’s collective immunity will have fallen.
This will make people more susceptible to factors that drive waves, such as the cold weather leading to people mingling indoors, and contagious new variants.
“The key thing is to reduce close contact with others when symptoms hit. We are generally most contagious in the few days after symptoms surface,” Dr Simon Williams, a behavioural scientist and public health expert at Swansea University, said.
New variants
Scientists have spotted several Covid subvariants that have the potential to spark a new wave.
It is still too early to say how much of a threat they pose but scientists are watching them closely as the current dominant variants – known as XEC and KP3.1.1 – show signs of running out of steam, paving the way for new subvariants to take over.
“As XEC and KP3.1.1 seem to have stagnated, it’s pretty much inevitable that whatever comes along next will cause another wave,” Professor Griffin said.
Scientists from Peking University have identified four new subvariants which have the potential to become significant, even dominant, new strains of the virus, in a development that could drive a further wave.
These are descended from JN.1, another significant Covid variant, and have mutations which may enable them to evade immunity built up from vaccines and prior infections better than the current variants, scientists say.
It is also possible that some of these subvariants could be fundamentally more contagious than the main existing ones or cause more severe symptoms.
“Several emerging JN.1 sublineages, such as LF.7.2.1, MC.10.1, NP.1, and, especially, LP.8.1, have demonstrated superior growth advantages compared to XEC,” said Jingyi Liu, of Peking University.
Professor Hunter added: “We will continue to see waves over coming years and decades but in general the severity of their impart will continue to become less.
“Of course, that assumes we do not get a mutation that significantly increases virulence, which is unlikely but not impossible.”
Booking a Covid Autumn booster
Although bookings for the NHS Autumn Covid booster are now closed, vaccinations are still being provided in certain locations until the end of January for those who are eligible. You can find details on how to find a walk-in Covid vaccination site at this link.
Those who are eligible for a free booster include people who:
- are aged 65 or over
- are pregnant
- are aged 6 months to 64 years and have an increased risk of getting seriously ill from Covid because of a health condition or treatment
- live in a care home for older adults
- are a frontline health or social care worker
Those who are not eligible can get the vaccine privately through Boots or from an independent pharmacist participating in the Pharmadoctor scheme.
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