Skeptics may have an extra reason to reconsider the upshots of vaccines: Two recent studies showed that flu and pneumonia vaccines reduced people’s risk of Alzheimer’s by as much as 30 percent.
The COVID-19 vaccines currently rolling out in the U.S. have not only been determined safe, but also effective beyond expectations. Even so, surveys have shown that some people are hesitant to take the COVID-19 vaccine or do not plan on getting one at all. Now, skeptics may have an extra reason to reconsider the upshots of vaccines in general: Early research shows that certain widely distributed vaccines may offer benefits beyond just immunity against an infection, such as helping to fend off Alzheimer’s.
Two recent studies showed that flu and pneumonia vaccines significantly reduced people’s risk of Alzheimer’s. The findings presented at a conference last year highlight that vaccines are not only critical to public health efforts of stemming and preventing deadly outbreaks of infectious diseases, but some may also play a role in protecting people’s cognition and brain health.
Alzheimer’s Association Chief Science Officer Maria C. Carrillo said continued research into the lasting health benefits of vaccines is critical in helping people understand that vaccines may be one among many factors linked to reducing dementia risk.
“With the COVID-19 pandemic, vaccines are at the forefront of public health discussions,” Carrillo said in a news release. “It is important to explore their benefit in not only protecting against viral or bacterial infection, but also improving long-term health outcomes.”
“It may turn out to be as simple as if you’re taking care of your health in this way — getting vaccinated — you’re also taking care of yourself in other ways, and these things add up to lower risk of Alzheimer’s and other dementias,” she continued.
Exploring the Link Between Flu, Pneumonia Vaccines and Alzheimer’s
According to the Alzheimer’s Association, past research has suggested that vaccination may be protective against cognitive decline, but there have been no large and comprehensive studies examining the link between flu vaccines and Alzheimer’s risk.
To fill the gap in research, a team from University of Texas combed through medical records of more than 9,000 people age 60 and up.
The researchers found that people who received at least one flu shot saw a 17 percent reduction in risk of Alzheimer’s. For people who got regular vaccinations, their risk dropped another 13 percent.
Timing of a vaccination seemed to matter as well. The protective effects of the vaccinations were the strongest for people who received their first vaccine at the age of 60, compared to those who waited until age 70.
In a separate study, scientists examined the link between the pneumonia vaccine and risk of Alzheimer’s in more than 5,000 older adults. People between the ages of 65 to 75 who received the vaccine had a reduced risk of developing Alzheimer’s of 25 to 30 percent. Those who did not carry a gene that increases risk for Alzheimer’s had the largest reduction in risk of up to 40 percent.
However, the researchers did not find any additional reduction in risk for people who received a flu vaccine as well as a pneumonia vaccine.
How Vaccines May Protect Against Alzheimer’s
While it’s unclear exactly why vaccines are associated with the risk of Alzheimer’s, researchers have proposed several theories.
Albert Amran, a medical student at the McGovern Medical School at UTHealth and a researcher in the study of flu vaccines and Alzheimer’s, told WebMD that vaccines may protect against neurological complications of an infection by preventing a viral infection in the first place.
The researchers found that people who received
at least one flu shot saw a 17 percent reduction in risk of
Alzheimer’s. For people who got regular vaccinations,
their risk dropped another 13 percent.
Dr. Scott Kaiser, a geriatrician and the director of Geriatric Cognitive Health for Pacific Neuroscience Institute at Providence Saint John’s Health Center, said coping with an infection of flu or pneumonia can exert a heavy toll on the brain, especially in severe cases of infections. By protecting people from infections, vaccinations may, in turn, safeguard people’s brain functions.
“Getting sick with the flu or pneumonia, particularly with bad cases, can be taxing on the brain and increase your long-term risk of dementia,” Kaiser told Healthline. “So protecting yourself from flu and pneumonia, through vaccination, may very well be protecting your brain too.”
Scientists also speculate that vaccines may bolster the overall immune system. According to Svetlana Ukraintseva, an associate research professor in the Biodemography of Aging Research Unit at Duke’s Social Science Research Institute and a researcher in the study of pneumonia vaccines and Alzheimer’s, certain vaccines can lead to effects beyond their intended targets. While some of these effects may be harmful, others could help people build resilience.
“[Some vaccines] are known for so-called off target effects, which can be beneficial or detrimental,” Ukraintseva said in a 2020 seminar. “In the case of beneficial effects, they sometimes improve mortality, survival and risk of other diseases.”
Another factor that may contribute to the recent findings is that people who get vaccinated may be more likely to take better care of themselves, and live a healthier lifestyle. They may also see their doctors more frequently and receive more medical care.
Scientists say that more studies are needed to explore the biological mechanisms that may explain the link between vaccines, infectious diseases, and the risk of Alzheimer’s. Carillo of the Alzheimer’s Association added that large, diverse clinical trials are necessary to inform whether vaccinations can be an effective public health strategy to reduce risk of dementia.
Is the COVID-19 Vaccine Safe?
Regardless of the link between vaccines and Alzheimer’s, scientists agree that vaccines are one of the greatest medical advances in modern times, protecting people against illnesses such as flu, pneumococcal disease, whooping cough, measles, rubella and mumps.
In the fight against COVID-19, researchers have been able to use novel approaches to develop vaccines at lightning speed without compromising the safety of the vaccines and the scientific rigor of the development process. In part, the efficiency of the process is due to years of research and development.
Vahia added that vaccinations could
open the door for older adults to return to
some degree of normalcy in their lives.
However, doubts about the vaccine remain. A December poll by the Kaiser Family Foundation (KFF) showed that about a quarter of the American public were hesitant about getting a COVID-19 vaccine, even if it were available for free and deemed safe by scientists. An earlier survey by UsAgainstAlzheimer’s found that in the Alzheimer’s community, one in 10 respondents said they would not take the vaccine, and 30 percent were unsure. But the KFF poll showed that a growing share of the general public have reported that they would definitely, or probably get one.
Dr. Ipsit Vahia, a geriatrics psychiatrist at McLean Hospital, said that in considering whether or not to get the COVID-19 vaccine, it is important to remember that older adults are at heightened risk for severe illness and death from COVID-19.
“We know well how devastating [COVID-19] has been in assisted living and nursing home communities,” Vahia told Being Patient. “While there may be unknown risks [with the COVID-19 vaccine], when deciding whether or not to take the vaccine, the higher risk of suffering or even death from COVID-19 is, to my mind, a more significant and a better established indicator.”
Vahia also noted that for older adults who recover from COVID-19, some may experience its chronic effects from loss of taste or smell, or mental health symptoms like depression.
People with severe cases of COVID-19 may experience neurological conditions ranging from stroke and brain fog, to seizures and paralysis.
While some people may feel a degree of anxiety about the safety, side effects and effectiveness of the COVID-19 vaccines, experts say that older adults are not at higher risk of more severe side effects. According to AARP, clinical trials showed that older adults actually experienced less side effects, and the vaccines appear to be just as effective for them as the younger population.
Research in COVID-19 vaccines is still in its early days, and it’s too early to know whether the vaccines have a link with the risk of Alzheimer’s. But experts understand that vaccinations play a central role in protecting people from a virus that has wreaked havoc across communities, especially among long-term care facilities. Vahia added that vaccinations could open the door for older adults to return to some degree of normalcy in their lives. Once COVID-19 vaccines are widely available in the community, he said restrictions in places like long-term care facilities would likely ease, granting older adults more opportunities to engage socially, enjoy the outdoors, and participate in group-based activities — pursuits that are central to their mental and physical wellbeing.
Contact Nicholas Chan at firstname.lastname@example.org