The world could see a resurgence in flu next winter due to people having low immunity, experts have warned.
According to some reports, the disease has been "almost wiped out" with the number of people being struck down by it dropping to its lowest levels in 130 years.
But now experts are concerned that the lack of circulation of influenza means people's immunity levels have fallen, and could result in a dramatic flu outbreak next winter.
Watch: Flu rates drop dramatically due to COVID-19 Precautions
Sage member Professor John Edmunds, from the London School of Hygiene & Tropical Medicine, told the Telegraph: "If I had to gamble on it, then I would guess that we are likely to get a more severe epidemic in the coming winter - assuming restrictions are fully lifted by then.
“We have effectively missed out on flu this winter, so the levels of immunity are less than would be typical. In fact, it is not impossible that we will have an out-of-season epidemic perhaps in the autumn, rather than winter."
Last month the The Sunday Times reported that figures showed the number of people being struck down by flu had dropped by 95%, suggesting it had nearly been eradicated.
The newspaper reported that in the second week of January, the number of flu-like illnesses reported to GPs was just 1.1 per 100,000 compared to a five-year average rate of 27 per 100,000.
Social distancing measures have not only reduced transmission of SARS-CoV-2, but also of the flu as seen here in this remarkable chart. Note the absence of any ‘spike’ in the 2020/2021 season indicated by the red arrow.
How have these measures impacted other viruses?
— Nicola Oliver | Medical Intelligence (@NicolaMedical) February 11, 2021
Earlier this month Nicola Oliver, a director and public health expert at Medical Intelligence, showed the effects of the COVID pandemic on other viruses in a Twitter thread, saying: "Social distancing measures have not only reduced transmission of SARS-CoV-2, but also of the flu as seen here in this remarkable chart.
"Note the absence of any ‘spike’ in the 2020/2021 season indicated by the red arrow."
Some experts have also said low immunity will make it difficult to predict which strain of flu will hit next, and therefore which vaccine to develop, the Telegraph reported.
Dr John McCauley, director of the Worldwide Influenza Centre at the Francis Crick Institute, told the newspaper: “I don’t think we’ve been in a position with so little flu in circulation for over a century.
"What that means is overall in the population there’s less experience and therefore there’s less boosting of immunity.”
On Sunday, Prof Edmunds also warned that while the UK is in a “really strong position” in the fight against coronavirus thanks to the vaccine rollout, until everyone – including children – has been vaccinated there will be “significant risk of a resurgence” of the virus.
Watch: What is long COVID?