UK Health Security Agency News and Media

22 Jun 2023

Excess deaths associated with flu highest in 5 years

The UK Health Security Agency has published its annual flu report for the 2022/2023 flu season, the first-time flu has been widespread since the COVID-19 pandemic began. A new UKHSA interim analysis indicates that excess deaths in England associated with flu infection were higher (14,500) than the average figure (13,500) for the 5 years before the pandemic.

This is the highest figure since the 2017/2018 season, when there were 22,500 excess deaths associated with flu.

The report also shows that the season started relatively early in the winter, but peaked quickly. Hospitalisations across all ages were higher than average, although some of this may be attributed to increased testing by the NHS compared to previous winters.

There are likely multiple reasons for the above average number of deaths and hospitalisations, but the impact will have been influenced by the dominant circulating strain. Influenza A(H3N2), which was the predominant subtype in 2022/23, is known to be more severe in older age groups. In addition, there is evidence to suggest that lower population immunity due to reduced flu circulation from social distancing measures during the pandemic meant that, overall, the population was more susceptible to catching flu than usual, contributing to the timing, shape and scale of the influenza season.

The vaccines were well matched to the predominant circulating strain. Vaccine effectiveness against being hospitalised by flu was analysed by looking at patients who were tested for influenza, and was consistent with analysis from previous seasons. The analysis found that getting vaccinated cuts the risk of being hospitalised by flu by a quarter in adults aged 65 and older, a third in other adults and reduces the risk two-thirds in children. This is on top of the collective protection we all get from the vaccines reducing flu transmission.

This indicates that flu vaccination again this season had an important role preventing serious illness and keeping people out of hospital.

Dr Conall Watson, Lead Flu Epidemiologist, at UKHSA, said:

“Flu returned at scale last winter after being locked out by COVID-19 control measures. Lower population immunity following flu’s absence played a part in the season starting relatively early and led to lots of people catching flu in a short timeframe.  Many people needed advice from NHS 111 services and there were high numbers of severe flu episodes that required hospital care, placing pressure on the heath system.

“The best protection against getting seriously ill and needing hospitalisation is to get the flu vaccine ahead of winter. We have clear evidence that the protection from last season’s vaccine programme helped prevent a much worse winter. Plans for the delivery of this winter’s vaccine programme are well underway and we strongly advise all those eligible to take up the offer of vaccination this autumn.”

 

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Notes to editors

  • The average number of excess deaths associated with flu is around 13,000 over the 5 to 10 years prior to the COVID-19 pandemic with the worse winter seasons seeing flu-associated deaths exceeding 20,000.
  • The interim mortality analysis uses a new way of looking at excess deaths to tease apart those attributable to flu, COVID-19 and cold weather. In 2022/23 there were 10,500 excess deaths associated to COVID-19 and 5,500 associated with cold weather.
  • Older adults, pregnant women, and those in clinical risk groups, are all at higher risk from flu and will be eligible for the flu jab this winter. Many children are also eligible for a nasal spray flu vaccination this winter.
  • National flu immunisation programme 2023 to 2024 letter: https://www.gov.uk/government/publications/national-flu-immunisation-programme-plan/national-flu-immunisation-programme-2023-to-2024-letter