Two international clinical trials found that a high-dose flu vaccine reduced flu- and pneumonia-related hospitalizations by 8.8% in older adults with chronic lung diseases, like asthma and COPD.
- Analysis evaluated 31,976 participants aged 65+ with chronic lung disease across Denmark and Spain from 2022-2025
- The high-dose vaccine contains four times the active ingredient to stimulate stronger immune response in older adults
- Findings support recommending high-dose flu vaccines for seniors with chronic lung disease to reduce hospitalizations
Older individuals with chronic lung disease are at increased risk of hospitalization for flu or pneumonia. According to combined results of two large, international clinical trials, this risk can be reduced with a high-dose flu vaccine.
Lisa Steen Duus, MD, a researcher from Gentofte Hospital in Copenhagen, Denmark, presented the crucial findings at the European Respiratory Society (ERS) Congress in Barcelona, Spain.
“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 hospitalization,” said Dr. Duus in an ERS press release.
The research results came from two randomized, controlled studies that compared a high-dose flu vaccine with a standard-dose flu vaccine in patients aged 65 years and older. One trial ran in Denmark over consecutive flu seasons from 2022 to 2025. The second trial ran in Galicia, Spain, over flu seasons from 2023 to 2025. Early analysis of the combined results showed the high-dose flu vaccine was beneficial in the at-risk population, the researchers said.
“Although high-dose flu vaccines are designed to produce a stronger immune response in older adults, there has been limited randomized evidence specifically showing whether they provide better protection against serious illness in people with chronic lung disease,” Dr. Duus said. “We therefore wanted to investigate whether a high-dose vaccine could reduce hospitalizations in this particularly vulnerable group.”
While the two studies enrolled more than 466,000 participants, approximately 7% (31,976) of individuals had a chronic lung disease, such as asthma, COPD, bronchiectasis, bronchitis, cystic fibrosis, tuberculosis, sarcoidosis or lung transplantation.
Participants in the chronic lung disease group randomly received either a standard-dose flu vaccine or a high-dose flu vaccine, which contained four times the amount of the active ingredient that stimulates the body’s immune response. Researchers monitored the participants through May, when flu season is fully over in Europe, and recorded any post-vaccine hospitalizations.
Dr. Duus reported that that high-dose flu vaccine reduced flu- or pneumonia-related hospitalizations by 8.8% in comparison with the standard-dose flu vaccine. Hospitalizations for other related conditions, including cardiorespiratory vaccine, were also reduced with the higher dose flu vaccine.
“Being hospitalized creates a considerable burden on patients, families and healthcare systems, so even a modest reduction could have meaningful public health benefits,” Dr. Duus said. “For that reason, these results support considering high-dose flu vaccines for older adults, including those with chronic lung disease, when developing vaccine recommendations.”
