Flu has left more than 2,000 Britons needing life-or-death treatment in an intensive care unit (ICU) this winter, even though the virus is circulating at unusually low levels.
Senior doctors said as many people were at risk of dying as during the pandemics of 2009-10 and 2010-11, despite the small numbers contracting the virus.
One leading expert said the strain of flu this winter was so virulent that it had left people who were previously fit and healthy critically ill, some of whom hospitals have been unable to save. Those who have not had this year’s winter flu vaccine appear to be most at risk.
Pregnant women and adults with a long-term medical condition who contract the virus are most likely to end up struggling to breathe so badly that they could die, said Public Health England (PHE). This strain of flu is following a dangerously different pattern than usual, with comparatively few people visiting their GP about it but large numbers becoming so unwell they risk dying.
In total, 2,182 people in the UK have had to be admitted to an intensive care unit (ICU) or high-dependency unit (HDU) because of flu since the start of October. That is more than the 2,045 who needed such care in the same period last year, when the virus was much more prevalent. Flu has killed 195 this winter, though that is down on the 241 deaths that occurred in the same period in 2017-18.
Dr Simon Ashworth, a consultant in intensive care at St Mary’s hospital in London, who has specialised in such care for 25 years, said: “This is the worst flu season I have ever known.” At least six of his ICU’s 32 beds have been taken up with flu patients since mid-December.
The five NHS trusts in England that provide extra corporeal membrane oxygenation (ECMO), the highest level of lifesaving support available for patients who cannot breathe, have also had to use the technology in recent weeks on flu patients.
Ashworth said: “Although the overall incidence of flu reported by Public Health England is, if anything, lower than last year, our experience at St Mary’s has been that we have seen more patients with severe influenza requiring intensive care than we saw even in 2010.
“Colleagues from other hospitals have reported similar experiences, including those from ECMO centres, which have reported high levels of activity and running at close to capacity. Our impression is that patients who have ended up in ICU have generally not been vaccinated so even if the vaccine hasn’t been completely protective, it has reduced the risk of life-threatening infection.”
Dr Nick Scriven, the president of the Society for Acute Medicine, whose members help care for flu patients in hospital, said the unusual combination of low levels of the infection but high numbers of people left severely unwell could mean that it was proving deadlier this year.
He said: “From the relatively lower rates of GP consultation and so far hospital admission compared to the higher levels of ICU/HDU need and nearly 200 flu-related deaths, it could point to this year’s strain being particularly virulent and causing more extreme reactions in infected patients.
“I would urge anyone who requires vaccination but has not had it yet to get vaccinated as circulating levels are still significant and the illness caused very severe.”
At Leicester Hospitals trust, which is also an ECMO centre, more patients have needed ECMO to breathe since the last UK flu pandemics.
Dr Chris Harvey, director of the trust’s paediatric and adult ECMO programme, said it had treated 42 patients in intensive care or high dependency and another 25 with ECMO, this winter.
He said: “Since the start of December we have treated a total of 25 critically ill patients with ECMO support with confirmed influenza A in Leicester. This represents the highest number of flu patients we have managed with ECMO since the pandemics of 2009-10 and 2010-11.
“All of our patients were previously fit and well and were rendered critically ill by the virus. None of these patients had been vaccinated against flu this year.”
The most recent flu surveillance data, released by PHE last Thursday, showed that primary care services, mainly GP surgeries, were seeing low-intensity levels of the virus in the week ending 10 February. Only 23.1 people per 100,000 of population were reporting flu-like symptoms.
Despite that, both the number of people admitted to hospital with flu, and those needing admission to an intensive care or high-dependency unit, were at high-impact levels. In that week alone, 269 people ended were sent to an ICU or HDU, compared with 177 last year.
Dr Mary Ramsay, PHE’s head of immunisations, said: “Flu is having less of an impact this year than last. However, we know that we are seeing high hospital admission rates due to flu. The main strain circulating this season is A(H1N1)pdm09, which particularly tends to affect younger and middle-age adults.
“At-risk groups who are affected by this strain, pregnant women and adults with long-term conditions, are at increased risk of more severe consequences of flu, which may be why we are seeing higher rates of ICU and HDU admissions.”
PHE data shows that, by the fourth week of January, 44.8% of pregnant women received the winter flu vaccine, as had just 46.7% of those under 65 and 71.2% of those over that age who are in a clinical risk group owing to an underlying medical condition such as diabetes. Official advice is that everyone in at-risk groups should have the jab to protect themselves.
