Health Benefits of Vaccines in Older Adults
It is well-known that vaccines help prevent a number of illnesses, but many older adults do not receive vaccinations routinely, some due to weakened immune systems and chronic illnesses. The main reason to be vaccinated against conditions such as shingles, influenza, COVID, and Respiratory Syncytial Virus (RSV) is that vaccines effectively reduce the risk of contracting these conditions, or reducing their severity if contracted. However, a growing body of research suggests that vaccines in older adults may have additional far-reaching health benefits in addition to prevention of these illnesses.
Off-Target Benefits of Vaccines in Older Adults
Strong evidence of off-target benefits of vaccines in older adults has been present for 25 years, in that recipients of influenza vaccines show reduced cardiovascular risk. Healthy older adults vaccinated against flu have lower risks of hospitalization for heart failure, as well as stroke, heart attack, pneumonia, and respiratory infections than those who do not receive flu vaccines. RSV vaccines have been available for only a few years, but a recent Danish study of older adults noted a nearly 10 percent decline in cardiorespiratory hospitalizations in those vaccinated against RSV vs. a control group. Vaccination against Covid-19 is known to reduce the risk of developing long-COVID, a condition which effects both physical and mental health. Dr. William Schaffner, an infectious disease specialist at Vanderbilt University Medical Center, notes that the list of off-target benefits for vaccines is lengthening, as research in this area has accelerated over the last ten years.
Vaccines’ Role in Decreasing the Risk of Dementia
A meta-analysis performed in 2022 reviewed five studies including 292,157 older participants. This research showed that influenza vaccines decreased the risk of dementia over a mean follow-up period of nine years, and potential confounding variables (such as low education, physical inactivity, smoking, obesity, and air pollution) did not account for this effect. The authors concluded that influenza vaccines may aid in the prevention of dementia. In a January 2026 New York Times article, journalist Paula Span noted that among other off-target benefits, many vaccines seem to lower the risk of dementia. Dr. Stefania Maggi, a geriatrician and senior fellow at the Institute of Neuroscience at the National Research Council in Padua, Italy, was the lead author of a recent meta-analysis in the British journal Age and Ageing. This study found reduced risks of dementia after vaccination for a number of diseases.
The studies that draw associations between vaccinations and the prevention of dementia are observational, and may be criticized in that strong associations between vaccination and off-target benefits can be noted, but causal connections cannot be assumed. It could be argued, for example, that vaccinated patients practice other healthy habits (such as exercise, regular medical care, and healthy nutrition), which differentiates their health outcomes from those who are not vaccinated. However, a Stanford study of the shingles vaccine in Wales offers epidemiological evidence to support the idea that viruses that affect the nervous system can increase the risk of dementia. In 2013 in Wales, the shingles vaccine (containing a live-attenuated, or weakened form of the virus) became available only to those who were 79 years old but had not yet turned 80. People who were 78 became eligible for the vaccine when they turned 79, and so on each year; this was done to ration to limited supply of the vaccine. Half of those eligible 79 year olds received the new shingles vaccine. The findings (published in Nature) note that seven years later, the rate of dementia in participants who were eligible for the shingles vaccine was 20% lower than those who were slightly older, narrowly missed the age cutoff, and were therefore not vaccinated. This situation allowed for naturalistic circumstances that were very similar to a randomized controlled trial. The two comparison groups were not statistically different in terms of education, frequency of other vaccines or preventative treatments, or health conditions such as heart disease, cancer, or diabetes. The only difference found by the researchers between these two groups was that the group that had access to the vaccine developed dementia and Mild Cognitive Impairment at a lower frequency than those who did not have access to the vaccine. Additionally, a follow-up study published in Cell noted that those who received the vaccine and already had dementia appeared to experience slowed progression of the disease. The researchers found that people who received the vaccine after a dementia diagnosis were significantly less likely to die from dementia than from another cause (per cause of death noted on death certificates) than those who did not receive the vaccine. Additionally, the study found that the vaccine’s protection against dementia was more pronounced in women than in men. This may be because women contract shingles more often than men, and on average women’s antibody responses to vaccinations are higher than men’s. The findings from the sample of people in Wales have been replicated via study of health records in England, Australia, New Zealand, and Canada. Dr. Maggi notes that many infections are associated with the onset of vascular dementia and Dementia of the Alzheimer’s Type, and vaccination against shingles, influenza, Tdap (tetanus, diphtheria, and pertussis) and pneumococcal infection are all associated with reduced risk of dementia.
How May Vaccines offer Multiple Health Benefits to Older Adults?
How and why could vaccines protect older adults by offering multiple health benefits including off-target benefits? Most hypotheses addressing this phenomenon focus on the inflammation that arises when the immune system mobilizes to fight off an infection. This inflammation damages the body, and the damage from inflammation can last much longer than the initial illness. This prolonged inflammation is hypothesized to allow other infections to occur, narrow blood vessels, and lead to strokes and heart attacks. In addition, hospitalization of older adults is a risk factor for dementia. Hospitalization results in deconditioning and delirium, as well as causing or exacerbating other health issues. When vaccines ward off illnesses, they may reduce hospitalization rates, and thus offer additional protection to cognitive health.
If you are concerned about cognitive changes related to aging, Mild Cognitive Impairment, or dementia and you are interested in assessment, please feel free to reach out to me by email at amy@amyblackmonphd.com.