Excess flu deaths in England highlight the importance of vaccination, according to UKHSA

The UK Health Security Agency (UKHSA) has released a new interim analysis revealing a concerning increase in excess deaths associated with flu infection in England. The report indicates that the number of excess deaths in the 2022-2023 flu season reached 14,500, surpassing the five-year pre-pandemic average of 13,500.

These figures represent the highest since the severe 2017-2018 season, which saw 22,500 excess flu-related deaths. The analysis sheds light on the impact of the dominant circulating strain, the role of reduced population immunity due to pandemic-related measures, and the effectiveness of flu vaccinations in preventing severe illness and hospitalisation.

The report notes that the flu season in England began earlier than usual in the winter and reached its peak quickly. Hospitalisations across all age groups were higher than average, partly due to increased testing by the National Health Service (NHS) compared to previous winters.

The reasons behind the elevated number of deaths and hospitalisations are likely multifaceted, with the dominant circulating strain playing a significant role. Influenza A(H3N2), the predominant subtype during the 2022-2023 season, is known to be more severe among older age groups.

The analysis suggests that lower population immunity resulting from reduced flu circulation due to social distancing measures during the pandemic contributed to the population's increased susceptibility to catching the flu. This vulnerability likely influenced the timing, shape, and scale of the influenza season. The absence of significant flu activity in previous seasons may have led to a larger number of individuals contracting the flu in a condensed timeframe once the virus returned.

Vaccine effectiveness and prevention of severe illness

Despite the challenging circumstances, the report highlights that the flu vaccines used in the 2022-2023 season were well-matched to the circulating strain. Analysis of vaccine effectiveness against hospitalisation revealed consistent results with previous seasons.

The study found that vaccination reduced the risk of hospitalisation due to flu by 25 per cent in adults aged 65 years and older, 33 per cent in other adults, and two-thirds in children. These findings, combined with the collective protection resulting from reduced flu transmission due to vaccinations, indicate that flu vaccination played a crucial role in preventing serious illness and alleviating pressure on healthcare systems.

Dr Conall Watson, a Consultant Epidemiologist at UKHSA, stressed the impact of the flu's return after being mitigated by COVID-19 control measures. Lower population immunity following the absence of significant flu activity likely contributed to the early onset of the season and a higher number of people contracting the virus within a short timeframe. The strain on the healthcare system was evident, with numerous severe flu cases requiring hospital care and individuals seeking advice from NHS 111 services.

Dr Watson emphasised that getting vaccinated ahead of the winter season provides the best protection against severe illness and hospitalisation. The evidence from last season's vaccine programme indicates that vaccinations helped prevent a potentially worse flu season. As plans for this winter's flu vaccine programme are underway, it is strongly advised that all eligible individuals take advantage of the vaccination offer.

The UKHSA's interim analysis of the 2022-2023 flu season in England highlights the concerning increase in excess deaths and hospitalisations associated with flu infection. The dominant circulating strain, reduced population immunity due to pandemic-related measures, and the early onset of the season are factors contributing to these outcomes.

However, the report also underscores the importance of flu vaccination in preventing severe illness and reducing the burden on healthcare systems. The findings provide a clear message that vaccination remains a crucial tool in safeguarding public health and should be embraced by eligible individuals to mitigate the impact of future flu seasons.