High-dose flu vaccine cuts hospital admissions in elderly with lung disease

Combined results from two large clinical trials suggest that high-dose influenza vaccination offers older people with chronic lung disease greater protection against serious illness than a standard-dose vaccine

A high-dose influenza vaccine reduced hospital admissions for influenza or pneumonia among older people with chronic lung disease, according to research presented at the European Respiratory Society (ERS) Congress in Barcelona, Spain in September.

The analysis combined data from two large randomised controlled trials and focused on 31,976 participants aged 65 years or older who had a chronic respiratory condition. The high-dose vaccine reduced hospital admissions for influenza or pneumonia by 8.8 per cent compared with the standard-dose vaccine.

“Influenza can be particularly serious for older people with chronic lung disease, such as asthma and chronic obstructive pulmonary disease. They are more likely to experience complications, such as pneumonia, deterioration of their existing lung disease and hospital admission,” said Dr Lisa Steen Duus of Gentofte Hospital in Copenhagen, Denmark, who presented the research.

High-dose influenza vaccines contain more antigen, the component that prompts the immune system to recognise and respond to the virus. The vaccine assessed in the trials contained four times as much antigen as the standard-dose formulation and was designed to produce a stronger immune response in older adults.

One trial took place in Denmark across three influenza seasons, from 2022–23 to 2024–25. The second took place in Galicia, Spain, across the 2023–24 and 2024–25 seasons. Together, the trials enrolled 466,320 people aged 65 years or older.

The latest analysis concentrated on the 31,976 participants, just under seven per cent of the total, who had a chronic lung disease. Their conditions comprised asthma, bronchiectasis, bronchitis, chronic obstructive pulmonary disease (COPD), cystic fibrosis, emphysema, interstitial lung disease, respiratory tuberculosis and sarcoidosis. The group also contained people who had received a lung transplant.

Approximately half received a standard-dose influenza vaccine, while the remainder received the high-dose formulation. Researchers recorded hospital admissions from 14 days after vaccination until the following May, by which time the European influenza season was largely complete.

As well as the 8.8 per cent reduction in admissions for influenza or pneumonia, high-dose vaccination reduced admissions associated with cardiorespiratory disease and hospital admissions from any cause.

“For older people with chronic lung disease and their families, these findings provide reassurance that high-dose influenza vaccination can offer better protection against serious illness that requires hospital treatment than a standard-dose vaccine,” Duus said.

“Hospital admission creates a considerable burden for patients, families and healthcare systems, so even a modest reduction could provide meaningful public-health benefits.

“These results support consideration of high-dose influenza vaccines for older adults, such as those with chronic lung disease, as authorities develop vaccination recommendations,” she added.

“Older people with lung disease face a greater risk of severe illness, hospital admission and death from influenza, which is why the ERRS recommends annual influenza vaccination for this group,” said Professor Thomas Wilkinson during the conference proceedings. He is chair of the ERS’ group on respiratory infections and immunology and a researcher at the University of Southampton, UK but did not take part in the study.

“This analysis indicates that a high-dose influenza vaccine could provide additional benefits for this vulnerable group,” Wilkinson concluded.