Introduction to Vaccines and Older Adults
The primary reason to be vaccinated against shingles is that two shots provide at least 90% protection against a painful, blistering disease that a third of Americans will suffer in their lifetimes, one that can cause lingering nerve pain and other nasty long-term consequences. The most important reason for older adults to be vaccinated against the respiratory infection RSV is that their risk of being hospitalized with it declines by almost 70% in the year they get the shot, and by nearly 60% over two years. And the main reason to roll up a sleeve for an annual flu shot is that when people do get infected, it also reliably reduces the severity of illness, though its effectiveness varies by how well scientists have predicted which strain of influenza shows up.
Off-Target Benefits of Vaccines
But other reasons for older people to be vaccinated are emerging. They are known, in doctor-speak, as off-target benefits, meaning that the shots do good things beyond preventing the diseases they were designed to avert. The list of off-target benefits is lengthening as “the research has accumulated and accelerated over the last 10 years,” said William Schaffner, an infectious disease specialist at Vanderbilt University Medical Center in Nashville, Tennessee. Some of these protections have been established by years of data; others are the subjects of more recent research, and the payoff is not yet as clear. The first RSV vaccines, for example, became available only in 2023.
Reduced Risks of Dementia
Still, the findings “are really very consistent,” said Stefania Maggi, a geriatrician and senior fellow at the Institute of Neuroscience at the National Research Council in Padua, Italy. She is the lead author of a recent meta-analysis, published in the British journal Age and Ageing, that found reduced risks of dementia after vaccination for an array of diseases. Given those “downstream effects,” she said, vaccines “are key tools to promote healthy aging and prevent physical and cognitive decline.”
Yet too many older adults, whose weakening immune systems and high rates of chronic illness put them at higher risk of infectious diseases, have not taken advantage of vaccination.
Vaccination Rates Among Older Adults
The Centers for Disease Control and Prevention reported last week that about 31% of older adults had not yet received a flu shot. Only about 41% of adults 75 and older had ever been vaccinated against RSV, or respiratory syncytial virus, and about a third of seniors had received the most recent COVID-19 vaccine. The CDC recommends the one-and-done pneumococcal vaccine for adults 50 and older. An analysis in the American Journal of Preventive Medicine, however, estimated that from 2022, when new guidelines were issued, through 2024, only about 12% of those 67 to 74 received it, and about 8% of those 75 and older.
Cardiovascular Risks and Vaccines
The strongest evidence for off-target benefits, dating back 25 years, shows reduced cardiovascular risk following flu shots. Healthy older adults vaccinated against flu have substantially lower risks of hospitalization for heart failure, as well as for pneumonia and other respiratory infections. Vaccination against influenza has also been associated with lower risks of heart attack and stroke. Moreover, many of these studies predate the more potent flu vaccines now recommended for older adults.
RSV Vaccine and Cardiovascular Effects
Could the RSV vaccine, protective against another respiratory illness, have similar cardiovascular effects? A recent large Danish study of older adults found a nearly 10% decline in cardiorespiratory hospitalizations — involving the heart and lungs — among the vaccinated versus a control group, a significant decrease. Lowered rates of cardiovascular hospitalizations and stroke did not reach statistical significance, however. That may reflect a short follow-up period or inadequate diagnostic testing, cautioned Helen Chu, an infectious disease specialist at the University of Washington and co-author of an accompanying editorial in JAMA.
Other Off-Target Benefits
Vaccination against still another dangerous respiratory disease, COVID, has been linked to a lower risk of developing long COVID, with its damaging effects on physical and mental health. Probably the most provocative findings concern vaccination against shingles, aka herpes zoster. Researchers made headlines last year when they documented an association between shingles vaccination and lower rates of dementia — even with the less effective vaccine that has since been replaced by Shingrix, approved in 2017.
Mechanisms Behind Off-Target Benefits
What causes such vaccine bonuses? Most hypotheses focus on the inflammation that arises when the immune system mobilizes to fight off an infection. “You have damage to the surrounding environment” in the body, “and that takes time to calm down,” Chu said. The effects of inflammation can far outlast the initial illness. It may allow other infections to take hold, or cause heart attacks and strokes when clots form in narrowed blood vessels. “If you prevent the infection, you prevent this other damage,” Chu said.
Conclusion
In conclusion, vaccines are not only effective in preventing infectious diseases but also offer off-target benefits that can improve the overall health and well-being of older adults. These benefits include reduced risks of dementia, cardiovascular disease, and other chronic conditions. As research continues to uncover the mechanisms behind these benefits, it is essential for older adults to take advantage of available vaccines and for healthcare providers to recommend them.
FAQs
Q: What are off-target benefits of vaccines?
A: Off-target benefits refer to the positive effects of vaccines beyond preventing the specific disease they were designed to prevent.
Q: Which vaccines have been shown to have off-target benefits?
A: Flu, RSV, COVID, and shingles vaccines have been associated with off-target benefits, including reduced risks of dementia, cardiovascular disease, and other chronic conditions.
Q: Why are older adults at higher risk of infectious diseases?
A: Older adults have weakening immune systems and high rates of chronic illness, making them more susceptible to infectious diseases.
Q: What can be done to improve vaccination rates among older adults?
A: Healthcare providers should recommend available vaccines, and older adults should take advantage of them to prevent infectious diseases and potentially reduce the risk of chronic conditions.
