High-Strength Flu Vaccine Linked to 55% Lower Alzheimer's Risk in Major Study
A major new study published in the journal Neurology suggests that older adults who receive a high-strength flu jab may have a significantly reduced risk of developing Alzheimer's disease. The research, involving nearly 200,000 adults aged 65 and over, found those given the high-dose vaccine had a 55 per cent lower risk of the condition, compared with a 40 per cent reduction among those receiving a standard jab.
Growing Evidence for Vaccination's Brain Benefits
These findings add to growing evidence that routine vaccinations may help protect the brain as we age. Previous studies have indicated that getting a flu shot each winter could help reduce the risk of dementia. Importantly, there is no suggestion that catching flu causes dementia; rather, scientists believe the benefit comes from vaccination later in life.
Vaccines – administered to more than 16 million people in England last winter alone – may assist the ageing immune system in reducing inflammation, a key driver of brain damage linked to dementia. As we get older, cells become more prone to damage and release chemicals that drive chronic inflammation, while the body becomes less capable of repairing itself.
This heightened inflammatory state increases the risk of illnesses such as cancer, dementia and heart disease. Scientists are increasingly exploring whether it may be possible to slow or even reverse this biological ageing process. Vaccines such as the high-dose flu jab may help strengthen the ageing immune system and dampen inflammation, potentially lowering dementia risk.
Stronger Protection with High-Dose Formulations
The protective effect appeared stronger in women, though the reason for this gender difference is not yet clear. Dr Paul Schulz, professor of neurology at McGovern Medical School at UTHealth Houston and director of the Neurocognitive Disorders Centre, explained: 'At age 65, the immune system becomes less effective at fighting infection. This is why a high-dose vaccine is recommended for adults aged 65 and over.'
Previous research from his team suggested that getting any flu shot could lower Alzheimer's risk. This new study demonstrates that a higher dose may offer even greater protection. Dr Avram Samuel Bukhbinder, a corresponding author and neurology fellow at Massachusetts General Hospital, said: 'Our findings suggest that selecting the high-dose vaccine could be an easy, safe, and widely available way to help protect the brain as we age.'
Relevance to UK Healthcare Policy
The findings are particularly relevant in the United Kingdom, where more potent flu vaccines are already part of routine care for older adults. As of the most recent flu season, the Joint Committee on Vaccination and Immunisation (JCVI) recommends 'enhanced' vaccines for adults aged 65 and over to counteract the natural weakening of the immune system.
This includes the high-dose inactivated influenza vaccine (IIV-HD), such as Efluelda, which is four times stronger than standard vaccines. Another option commonly used in the UK is the adjuvanted vaccine (Fluad), which contains an added ingredient to boost the immune response and provide longer-lasting protection.
The JCVI also recommends the recombinant vaccine (Supemtek), an egg-free jab considered equivalent in providing enhanced protection. These vaccines are offered free on the NHS to those aged 65 and over, generally from October each year.
Beyond Influenza Prevention
While flu vaccination has long been recommended for older adults to prevent influenza, this research highlights the added benefit of the high-dose shot for potentially reducing the risk of Alzheimer's disease. It is important to note that the study was observational, meaning it shows an association rather than definitive proof that the vaccine prevents Alzheimer's. Factors such as overall health and lifestyle could also influence the results.
In England, flu vaccine uptake for those aged 65 and over remains consistently high, with 74.9 per cent vaccinated in the 2024–25 season – close to the 75 per cent target set by the World Health Organisation, although uptake in 2023 was higher at 79 per cent.
Alzheimer's disease represents the most common form of dementia in the UK, accounting for 60 to 80 per cent of cases – roughly two in three people with the condition. The progressive disorder is caused by abnormal protein build-up in the brain, known as plaques and tangles, which gradually destroy brain cells.
This research provides compelling evidence that healthcare interventions already in widespread use may offer unexpected benefits for brain health in later life, potentially transforming our understanding of how routine medical care can support cognitive function as we age.
