COVID cases will continue to surge in the coming weeks as a new variant has become dominant.
JN.1, a sub-variant of the Omicron, is considered a "variant of interest" by the World Health Organisation (WHO), because of how quickly it's able to spread.
Infections of the new bug in the UK are likely to increase for another week or two, a scientist has warned.
JN.1 grew from 1 per cent of UK Covid cases at the end of October to account for 5 per cent by mid November.
It then soared to 51.4 per cent on Christmas Day - making it three times as common as the second biggest strain, according to the latest data from the CovSpectrum database.
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Professor Christina Pagel of University College London has said its rapid growth is sending the UK towards its highest infection rate ever.
Prof Christina told the inews: "Unfortunately, it is likely that this JN.1 wave has not yet peaked and will peak mid-January, either next week or the week after.
"And then infections will stay very high for a few weeks on the downward slope, too.
"I am sure this wave will rival the first two Omicron waves in 2022 and might even exceed them."
However, she said it is unlikely that hospitalisations will approach the levels seen during the previous Omicron waves.
Less immunity
Other scientists have warned about waning immunity.
Speaking to the Sun, Prof Peter Openshaw, from Imperial College London, said, "Immunity falls over time, and for many, it's been over a year since they had their last booster jabs."
The number of Brits getting vaccinated is not the only thing to have changed - the virus is also evolving.
Vaccines and natural immunity only work when a strong match between the antibody and the virus is circulating.
The more a virus mutates, the less effective antibodies are at fighting it.
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"The virus circulating now is quite different from the one we saw in 2020," Prof Peter said.
"The new virus has become so much better at transmitting from person to person, and it's likely only going to get better.
"It's also much better at evading the current immunity from infection and vaccination."
It is important to stress that the Covid bug, generally, is less virulent and dangerous now than it was in 2020.
"Infections will be milder now, and the impact is lower if you look at the hospitalisations and death rates," Dr Phil Gould of Coventry University told the Sun.
The latest ONS and UK Health Security Agency (UKHSA) winter infection survey, published on 21 December, estimated that 2.54 million people had Covid on 13 December – more than double the level seen at the start of that month.
Since then, infections are expected to have risen sharply, as people spent time together over Christmas and the virus thrives in cold conditions.
The next UKHSA influenza and Covid report on Thursday is expected to indicate how high infections have gone clearly.
Two new Covid symptoms
Some of the illness's hallmark symptoms, like a runny nose and a cough, are still lurking around.
But loss of taste and smell - once a typical sign of the bug - is now only reported by two to three per cent of infected Brits.
Fever, which used to be a more common sign, was only experienced by two per cent of people, according to the winter Covid report from the Office For National Statistics in the UK.
ONS scientists suggest that anxiety can also be a sign that someone has become infected - though experts don't know exactly why.
Almost 10 per cent of Brits with Covid have consistently reported anxiety, excess worrying or trouble sleeping since early November.
Meanwhile, the most common symptom of infection with the JN.1 variant was runny nose, with 31 per cent of patients reporting the symptom, the report said.
Some 23 per cent of people reported experiencing a cough, and 20 per cent a headache.
Nearly 20 per cent of people with the bug reported weakness and fatigue, 16 per cent reported experiencing muscle aches, and 13 per cent had a sore throat.
