New interim analysis from the UK Health Security Agency (UKHSA) indicates that excess deaths in England associated with flu infection were higher (14,500) than the average figure (13,500) for the five years before the pandemic.
This is the highest figure since the 2017 to 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 to 2023, 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 years 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, Consultant Epidemiologist, 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."
