Takeaway
Prioritize talking with patients about how vaccines not only prevent infection but support cognitive health. This is one way that patients can take steps to preserve brain function.
Lifelong Learning in Clinical Excellence | June 23, 2025 | 2 min read
By Mfon Umoh, MD, PhD, Johns Hopkins Medicine
As a geriatrician and memory care specialist, I care for older adults with cognitive decline. Many patients wonder what they can do to improve their cognitive health. In some visits I discuss vaccines. Vaccines play an important role in brain health, mostly by preventing infectious diseases that can directly and indirectly impact brain function.
Vaccines directly influence brain health by protecting against infections that cause harmful consequences like inflammation in the brain (encephalitis), seizures, and meningitis (inflammation of brain and spinal cord membranes). Vaccines protect against illnesses, like measles, mumps, rubella, and polio, that can have lasting negative consequences on brain development and function. Indirectly, vaccines against common conditions, like influenza (flu), COVID-19, or shingles, also influence cognitive health.
Several studies have brought national attention to the link between vaccines and brain health. We’ve known for years that adult vaccination is associated with a significantly lower risk of developing dementia and most studies supporting this have been population-based observational studies. A recent “Nature” article1 presented results from a natural experiment in Wales that found that people that received the shingles vaccine were 20% less likely to develop dementia over the next seven years compared to those that did not.
Beyond preventing infections, vaccines can also decrease the severity of infections. Infections can lead to inflammation in the brain, a condition that significantly affects the development and progression of dementia. Infections like COVID-19 can cause symptoms like brain fog in the short term which can persist (long COVID). Vaccination can decrease the severity of a COVID infection, and may decrease the risk of persistent symptoms, though studies are ongoing.
Vaccines also influence overall health, which indirectly impacts brain health throughout life. “The Lancet” commission outlined 14 modifiable risk factors for dementia.They acknowledge that vaccinations reduce risk or severity of inflammation and are good for general health, though their effect on dementia risk, from a population perspective, remains unclear. Nevertheless, good physical health supports overall individual brain health.
The cognitive health benefits of vaccines are universally agreed upon. Vaccines are safe, have been well-studied, and have tremendous benefit. Research evaluating causal relationships between vaccines and improved cognitive outcomes is ongoing but the cognitive benefits are not up for debate. Staying up to date with recommended vaccines is a critical step in promoting both physical and cognitive health. Helpful resources for vaccination schedules for older adults are The American Geriatric Society Older Adults Vaccine Initiative and the CDC.
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This piece expresses the views solely of the author. It does not represent the views of any organization, including Johns Hopkins Medicine.