The risk of being hospitalised for flu or pneumonia can be reduced with a high-dose flu vaccine for older people with chronic lung disease, according to the combined results of two large clinical trials presented at the European Respiratory Society (ERS) Congress in Barcelona, Spain [1].
The research was presented by Dr Lisa Steen Duus from Gentofte Hospital, Copenhagen, Denmark. She said: “Flu can be particularly serious for older people with chronic lung disease, such as asthma and COPD. They are more likely to develop complications, including pneumonia, worsening of their existing lung disease, and hospitalisation.
“Although high-dose flu vaccines are designed to produce a stronger immune response in older adults, there has been limited randomised evidence specifically showing whether they provide better protection against serious illness in people with chronic lung disease. We therefore wanted to investigate whether a high-dose vaccine could reduce hospitalisations in this particularly vulnerable group.”
The new research combines the results of two gold-standard randomised controlled trials comparing a high-dose flu vaccine with a standard-dose in people aged 65 and older. One trial ran in Denmark over three flu seasons (2022-23, 2023-24 and 2024-25) and one ran in Galicia, Spain over two flu seasons (2023-24 and 2024-25). Analysis of these trials has already shown that the high-dose vaccine is beneficial in older people overall [2].
In the new study, researchers looked specifically at trial participants who had a chronic lung disease, including asthma, bronchiectasis, bronchitis, chronic obstructive pulmonary disease (COPD), cystic fibrosis, emphysema, interstitial pulmonary disease, lung transplantation, respiratory tuberculosis and sarcoidosis. Between the two studies, this was 31,976 people, just under seven per cent of the total 466,320 trial participants.
Around half of the participants were randomly allocated to receive a standard dose of flu vaccine. The other half received a flu vaccine containing four times as much of the active ingredient that stimulates the immune response.
Researchers monitored the participants and recorded any who were hospitalised from 14 days after their vaccination until the following May when the flu season is largely over in Europe.
The high-dose flu vaccine reduced hospital admissions for flu or pneumonia by 8.8% compared with the standard-dose vaccine. The high-dose vaccine also reduced hospitalisations for several other conditions, including cardiorespiratory disease, and hospitalisation from any cause, compared to the standard-dose vaccine.
Dr Duus said: “For older people with chronic lung disease and their families, these findings provide reassurance that high-dose flu vaccination can offer better protection against serious illness requiring hospital treatment than a standard-dose vaccine.
“Being hospitalised creates a considerable burden on patients, families and healthcare systems, so even a modest reduction could have meaningful public health benefits. For that reason, these results support considering high-dose flu vaccines for older adults, including those with chronic lung disease, when developing vaccination recommendations.”
Professor Thomas Wilkinson, Chair of the European Respiratory Society’s Group on Respiratory Infections and Immunology and based at University of Southampton, UK, who was not involved in the research said: “A flu infection is unpleasant for anyone, but for some people it can be a serious health risk. Older people with lung disease have a greater risk of severe illness, hospitalisation and death from flu, which is why the European Respiratory Society recommends annual flu vaccination for this group.
“This research combines the results of two large and well-run studies comparing the standard-dose flu vaccine with a high-dose flu vaccine in people aged 65 and above. Researchers have looked specifically at people on the trial who had also been diagnosed with a lung disease, such as COPD or asthma. Their analysis shows that a high-dose flu vaccine could be even more beneficial in this group.”
Randomized controlled/clinical trial
People