Flu Shots May Reduce the Risk of Alzheimer’s & Related Dementias

Flu Shots May Reduce the Risk of Alzheimer’s

Researchers discovered that vaccines may lower the risk of getting Alzheimer’s and associated disorders by increasing the immune system.

There are several reasons to get a flu vaccination. However, there is one reason that might surprise you! A recent study suggests that flu shots may protect your brain.

According to the study, getting regular vaccines against influenza and other infectious illnesses, including whooping cough, shingles, pneumococcal pneumonia, tetanus, and diphtheria, may lower the risk of Alzheimer’s disease and associated dementias [1]. Paul E. Schulz, professor of neurology and director of the Neurocognitive Disorders Center at McGovern Medical School at UTHealth Houston, led the study.

The Recent Study

In the study, after tracking two groups for up to eight years—one vaccinated against the flu, the other not—the researchers discovered a statistically significant disparity in the incidence of Alzheimer’s.

The researchers obtained individuals from a national patient database, dividing them into two groups of 935,887 each, one vaccinated and the other not. The scientists ensured that both groups had a number of similar characteristics, including age, gender, frequency of medical visits, and specific medical conditions like high blood pressure and elevated cholesterol, to minimize the possibility of different factors influencing the results.
The research team discovered that receiving an annual flu vaccination for three years in a row decreased the chance of dementia by 20% during the ensuing four to eight years while receiving six doses doubled the reduction to 40%.

According to Schulz, the number of dementia cases in the vaccinated group was 47,889, whereas the number in the unvaccinated group was 79,630. There is a difference of over 30,000 cases.

Similar results of other vaccines

Schulz team also saw comparable outcomes with vaccinations against other infectious illnesses, such as pneumococcal pneumonia, shingles, and Tdap, which is a mix of tetanus, diphtheria, and pertussis (whooping cough), or tetanus and diphtheria without the pertussis component.

Shingles Vaccine

The researchers compared 198,847 individuals who had the shingles vaccines—Zostavax, the first shingles vaccine, and Shingrix, the most current one—against an equivalent number of patients who did not receive the vaccinations. During the eight-year follow-up, 16,106 vaccinated individuals had Alzheimer’s disease, compared to 21,417 unvaccinated patients — or 5,311 fewer people in the vaccinated group experienced dementia.

Tdap and Td Vaccines

The researchers studied two groups of 116,400 patients each, one vaccinated and the other not, using the Tdap and Td vaccinations. Over eight years, 8,370 vaccinated people had dementia, compared to 11,857 unvaccinated people — 3,487 fewer cases overall.

Pneumococcal Vaccine

Using pneumococcal vaccination, researchers examined two groups of 260,037 individuals, one vaccinated and the other unvaccinated. After eight years, they found 20,583 instances of dementia among the vaccinated, compared with 28,558 unvaccinated individuals – 7,975 fewer patients in the vaccinated group.

Results from other studies

Stanford University researchers discovered comparable outcomes in two UK-based studies that are currently unpublished and undergoing peer review. The first, conducted over seven years in an older population in Wales, indicates that vaccination with Zostavax prevented an estimated 1 in 5 new cases of dementia, according to the study’s lead researcher, Pascal Geldsetzer, an assistant professor of medicine at Stanford University’s division of primary care and population health [2].

The second study examined mortality statistics for Wales and England and discovered a five percent difference in the likelihood of dying from dementia over a nine-year follow-up, or one in twenty deaths prevented [3].

For both studies, the researchers divided the participants into two groups for comparative reasons based on the country’s birth date qualifying requirements. Those who turned 80 shortly before the program started were not eligible for the vaccination and remained so. However, those who became 80 shortly after the program commenced were eligible for the vaccine, which they got for free over the subsequent year.

Geldsetzer stated that the likelihood of receiving the shingles vaccination varied significantly between the two comparison groups, presumably due to a tiny age difference. This sets the study apart from other studies that only compare those who receive vaccinations with those who do not. According to the researchers, the results of this particular natural randomization imply a causal link.

How can the vaccine help against dementia?

A multitude of studies have revealed that people who receive flu and other infectious disease vaccines are less likely to develop dementia than the unvaccinated [2][4]. However, the experts are unsure about the reason. According to some, vaccinations minimize or lessen the chance of contracting infectious agents, which may have a role in the development of Alzheimer’s.

In contrast, Schulz believes that vaccines could reduce the immune system’s response to amyloid plaque – a naturally occurring protein that is present in unusually high levels in Alzheimer’s patients. The immune system perceives plaque as a foreign intruder and attacks it, resulting in persistent brain inflammation and the death of adjacent neurons, leading to dementia.

Vaccines may rescue brain cells that the body’s immune system might otherwise kill by suppressing the immunological reaction to amyloid. Additionally, vaccinations may enhance the immune system’s capacity to eliminate plaque. Fewer plaques result in reduced inflammation and brain cell death.

Schulz further added that they are unsure what the process is yet, but something is happening with the brain and immune system that appears to be making a significant effect.

According to experts, more research is needed to evaluate the vaccine’s effects on the brain.

References

  1. Harris, K., Ling, Y., Bukhbinder, A.S., Chen, L., Phelps, K.N., Cruz, G., Thomas, J., Kim, Y., Jiang, X. and Schulz, P.E., 2023. The impact of routine vaccinations on Alzheimer’s disease risk in persons 65 years and older: a claims-based cohort study using propensity score matching. Journal of Alzheimer’s Disease, (Preprint), pp.1-16.
  2. Eyting, M., Xie, M., Heβ, S. and Geldsetzer, P., 2023. Causal evidence that herpes zoster vaccination prevents a proportion of dementia cases. medRxiv.
  3. Michalik, F., Xie, M., Eyting, M., Heß, S., Chung, S. and Geldsetzer, P., 2023. The effect of herpes zoster vaccination on the occurrence of deaths due to dementia in England and Wales. medRxiv, pp.2023-09.
  4. Wiemken, T.L., Salas, J., Hoft, D.F., Jacobs, C., Morley, J.E. and Scherrer, J.F., 2021. Dementia risk following influenza vaccination in a large veteran cohort. Vaccine, 39(39), pp.5524-5531.
  5. Cimons, M. Flu shots may protect against the risk of Alzheimer’s, related dementias. The Washington Post. https://www.washingtonpost.com/wellness/2023/10/25/flu-shots-alzheimers-dementias-vaccinations-infectious-diseases/. Published Online: 25th October, 2023. Accessed: 7th December, 2023.
  6. Simpson, M.L. Flu Shots Might Lower Your Risk of Alzheimer’s and Other Dementias. People. https://people.com/flu-shots-could-lower-risk-of-dementia-8383636. Published Online: 27th October, 2023. Accessed: 7th December, 2023.
Share with your friends!

Leave a Reply

Your email address will not be published. Required fields are marked *

×
×
0
    0
    Your Cart
    Your cart is emptyReturn to Shop
      Calculate Shipping
      Apply Coupon
      home-icon-silhouette remove-button handshake left-quote check-circle user-icon