GPs in England have reported a big drop in cases of influenza, colds and other common infections – with cold rates now about a quarter of the five-year average, and flu at about a 20th of the usual level for this time of year.
Social restrictions brought in to curb transmission of coronavirus combined with an increased uptake of flu vaccine is the most likely explanation, experts say.
Surveillance data gathered during the southern hemisphere’s flu season had suggested the UK might expect to see a drop in the incidence of flu this winter. However, the scale of the drop in England is surprising given that children attended school and limited social mixing was permitted until the introduction of a full lockdown on 4 January.
The data is derived from patient reports of illness at up to 500 GP practices across England gathered by the Royal College of GPs’ (RCGP) Research and Surveillance Centre. “We record whatever symptoms people consult with and these are sent on to the Research and Surveillance Centre,” said Azeem Majeed, professor of primary care and public health at Imperial College London and a GP.
During December, rates of common cold symptoms reported to GPs were 0.3-1.2 per 100,000 persons, while for influenza-like illness this was 0.5-1.3 per 100,000 persons – well below the five-year average for this time of year. The incidence of other common infections including intestinal disease, strep sore throat and inner ear infections (often linked to respiratory illness) is also well below the five-year average, and may similarly reflect increased hand hygiene and decreased social mixing.
Equivalent data for Wales and Scotland was not immediately accessible, but is likely to show a similar pattern given that similar restrictions on movement and social mixing have been imposed there.
“I think this is real and reflects two things: overwhelmingly the main thing is that social distancing and lockdown measures dramatically reduce the transmission of cold, influenza and other respiratory viruses,” said Paul Little, a professor of primary care research at the University of Southampton. “There may be a smaller secondary effect in that people may be contacting their GP less with ‘normal’ cold and coughs – but that cannot possibly explain the huge differences observed. Similar trends were seen in Australia with their flu season – which basically did not happen there either.”
There has also been a reduction in hospital admissions for flu, Majeed added.
Another factor which may have contributed is increased uptake of the flu vaccine. “There has been an excellent take-up this year, with a record 77% of over-65s coming forward for their jab, which will be offering them protection from the flu,” said Prof Martin Marshall, chair of the RCGPs. “This is something general practice teams should be hugely proud of given the additional pressures under which they are delivering the expanded flu vaccination programme this year.”
“Flu can be a nasty illness and as we start to come in contact with people again – even following social distancing measures – it’s important that people maintain good hygiene. We’d also urge anyone who is eligible for the flu vaccine – now including 50-64 year olds – to come forward for their jab. This is best protection we have against flu and vaccines only work if people have them.”