The higher the frailty, the bigger the high-dose flu shot’s advantage
☕ Includes a question for the family ↓
FrailtyPart of a story we are following · 3 articles · See every update
If someone you love is frail, asking about a high-dose flu shot is a smart move. A large new study found that the more frailty an older adult had, the bigger the advantage of the high-dose vaccine over the standard one.
That matters because frailty is also what puts older adults at the highest risk of ending up in the hospital with flu or pneumonia. The stronger shot did the most for the people who needed it most.
How the study worked
Researchers in Denmark randomly gave a very large group of adults aged 65 and older either a high-dose or a standard-dose flu shot, over three flu seasons from 2022-23 to 2024-25. They then looked at who ended up in the hospital with flu or pneumonia, sorted by frailty risk, which was scored from each person’s hospital records over the previous 10 years. The results were published in September 2026 in The Lancet Healthy Longevity; the authors call them exploratory, the trial was open-label and funded by Sanofi, and the estimates for each frailty group were imprecise.
What they found
Frailty made a big difference in who got seriously sick. Hospital stays for flu or pneumonia were least common in people with low frailty risk, more common in those with intermediate risk, and most common in those with high risk.
The high-dose shot’s advantage followed the same staircase. It was smallest for people with low frailty risk, bigger for people with intermediate risk, and biggest for people with high risk. In other words, the frailer the person, the more the stronger shot helped keep them out of the hospital.
When the researchers treated frailty as a sliding score instead of three boxes, the pattern held: the higher the frailty, the bigger the advantage of the high-dose shot.
Safety looked the same for both vaccines. Serious health events were more common in frailer people, which is expected, but they showed up at similar rates whether someone got the high-dose or the standard shot.
What is a high-dose flu shot?
It is a flu vaccine made for adults 65 and older. Immune systems tend to respond less strongly to vaccines with age and frailty, so this version was developed to give older people a stronger response. It is given the same way as any flu shot, in one injection.
What you can do today
Call the pharmacy where you or your mom usually gets the flu shot and ask whether they have a high-dose flu vaccine in stock. Ask them to set one aside, or book a time to come in.
Talk about it at home
Some people’s bodies need extra help to fight off germs, like when a team that is a little tired needs a stronger coach. A stronger flu shot gives the body a bigger practice run before flu season. In this study, the people who were most frail seemed to gain the most from it.
Try it at home
How could scientists check whether a stronger shot really works better than a regular one, and not just look like it does? Think about why they gave shots to people by random chance.
Keep exploring
Copies this article and its questions so you can paste them into ChatGPT, Claude, Gemini or the AI you use, and keep the conversation going.
Questions and answers
- What is a high-dose flu vaccine?
- It is a flu shot with a stronger dose, made for adults 65 and older to give them a stronger immune response.
- Who benefited most from the high-dose shot?
- People with higher frailty risk. The higher the frailty, the bigger the advantage over the standard shot at preventing hospital stays for flu or pneumonia.
- Was the high-dose shot safe for frail people?
- Serious health events were similar in the high-dose and standard-dose groups within each frailty group.
- Were frail people hospitalized more often?
- Yes. Hospital stays for flu or pneumonia were most common in people with high frailty risk and least common in those with low frailty risk.
