Heart Talk - August 2020
The Two Vaccinations That Help Prevent Alzheimer’s Disease, Heart Attacks and Strokes
Heart-healthy and Stroke-free Living with Eric A. Goulder, MD, FACC
Being vaccinated against pneumococcal pneumonia reduced older adults’ risk for Alzheimer’s disease (AD) by up to 40 percent, depending on their individual genetic profile, according to a study by Svetlana Ukraintseva, PhD, of Duke University and colleagues. The research was presented at the virtual Alzheimer’s Association International Conference (AAIC) in July.
The team examined links between AD and pneumococcal pneumonia vaccination, with or without an accompanying seasonal influenza shot, in more than 5,100 men and women ages 65 and older who were participating in the Cardiovascular Health Study. The results were adjusted for age, race, birth cohort, education and smoking. The researchers also took into account a strong genetic risk factor for AD: carrying a variant called the G allele of rs2075650 in the TOMM40 gene.
“[This allele is] linked to [the] NECTIN2 gene, which is involved in blood-brain barrier permeability and vulnerability to infection,” Dr. Ukraintseva told Medpage today. Overall, in the entire group, those who were vaccinated against pneumonia between ages 65 and 75 had 30 percent lower risk for AD afterwards. However, among noncarriers of the G allele of rs2075650, risk for AD dropped by 38 percent, the study found. “This means that adult vaccination against pneumonia may reduce Alzheimer’s risk depending on individual genotype, which supports personalized prevention of Alzheimer’s disease,” Dr. Ukraintseva said.
The CDC and the BaleDoneen Method recommend the shot for everyone age 65 and older, as well as younger people with risk factors for pneumonia, such as heart failure, pulmonary disease, diabetes or smoking. The shot protects against infection by 23 types of pneumococcal bacteria and has been FDA-approved since 2000. Rates of the types of pneumonia the shot protects against have dropped by 99 percent in the U.S. since it was introduced, the CDC reports. However, pneumonia remains a major public threat — particularly to those who are not vaccinated — killing about 50,000 Americans a year, most of whom are over 65 or older.
Along with protecting against a dangerous infection — and the risk of being hospitalized with pneumonia during the COVID-19 pandemic — the pneumococcal immunization also has another life-saving benefit: A study of more than 84,000 people found that those who have been vaccinated against this disease were at lower risk for heart attack and stroke. Given these benefits, we recommend being vaccinated at age 50 if you have cardiovascular disease.
What effect does the seasonal flu shot have on risk for Alzheimer’s disease?
Another study presented at the same conference looked at links between annual flu shots and risk for AD in a propensity-matched set of 9,066 patients ages 60 and older. Key findings from the study by Albert Amran, a medical student at McGovern Medical School at The University of Texas Health Science Center at Houston, and a team of researchers include the following:
• Having at least one flu shot was associated with a 17 percent risk for Alzheimer’s disease.
• People who consistently got annual flu shots had 30 percent lower risk for AD.
• The protective effects of flu shots were strongest in those who received their first flu shot at a younger age. For example, those who got their first documented flu shot at age 60 benefitted more than those who waited until after age 60 to get their first flu shot.
“Our study suggests that regular use of a very accessible and relatively cheap intervention — the flu shot — may significantly reduce risk of Alzheimer’s dementia,” Amran stated in a news release from the Alzheimer’s Association. Dr. Ukraintseva’s study also reported that people who received a higher number of flu and pneumonia vaccinations between ages 65 and 75 had a 12 percent lower risk for AD, as compared to people who received fewer or no shots. The CDC recommends the annual influenza vaccination for everyone age 6 months or older, but cautions that certain people should check with their healthcare provider before being immunized.
Do seasonal flu shots help prevent heart attacks and strokes?
People who get a flu shot are significantly less likely to suffer heart attacks, transient ischemic attacks (TIAs, also known as “mini-strokes”) and other cardiovascular events in the following year, according to a large study presented at the American Heart Association’s virtual scientific sessions in July. The research was conducted by scientists from Texas Tech University Health Sciences Center Paul L. Foster School of Medicine in El Paso, Texas.
The team reported that in high-risk groups — such as people over age 50, those who are obese and those who live in nursing homes — seasonal flu vaccination was associated with a 28 percent reduction in heart attacks, 47 percent reduction in TIA and a 73 percent reduced risk for death in the following year. Using a database of more than 7 million patients who had been hospitalized, the researchers analyzed the rate at which the flu vaccine was given to patients designated by the CDC as being at high risk. The study also looked at cardiovascular outcomes in those who were vaccinated during their hospital stay versus those who didn’t get the shot.
The study adds to a large body of scientific evidence demonstrating that the flu shot may also be a vaccine against life-threatening CV events. Adults who are immunized have a 46 percent lower risk for fatal or nonfatal heart attacks, strokes and other major cardiovascular (CV) events over the subsequent 12 months, compared to those who received a placebo shot or no shot, according to a recent Harvard analysis that pooled results from randomized clinical trials involving nearly 7,000 men and women.
Another recent study found that people who are vaccinated early in the flu season (such as September or October) have a greater reduction in heart attack risk than those who wait until mid-November to be immunized. Many studies have shown that acute influenza infection is a strong, independent risk factor for heart attacks and strokes. Researchers report that up to 91,000 Americans die each year from CV events triggered by the flu. These grim statistics have prompted the American Heart Association and the American College of Cardiology to issue guidelines recommending flu shots for people with cardiovascular disease (CVD).
Why would flu and pneumonia shots have any effect on risk for Alzheimer’s disease?
Because these were observational studies, they were not intended to prove a cause-and-effect relationship between pneumonia and flu vaccinations and Alzheimer’s disease. “More research is needed to explore the biological mechanism for this effect — why and how it works in the body — which is important as we explore effective preventive therapies for Alzheimer’s,” remarked Amran.
“The fact that very different pathogens — viral, bacterial, fungal — have been linked to Alzheimer’s disease suggests a possibility that a compromised host immunity may play a role in Alzheimer’s through increased overall brain vulnerability to microbes,” Dr. Ukraintseva said. “Some vaccines show beneficial off-target effects on health that span beyond the protection against specific disease,” she told MedPage Today. “This could be because they may improve immunity on a broad scale.”
Another possibility is that by protecting against flu and pneumonia, these vaccines help people avoid the systemic inflammation that these diseases cause. As we recently reported, targeting brain inflammation is one of the newest strategies to prevent AD and other forms of dementia. Recently, 24 of the world’s leading experts on dementia prevention published a landmark paper in Lancet outlining lifestyle steps that could reduce risk for memory loss by up to 35 percent. These steps were designed to reduce brain inflammation and other factors that can set the stage for dementia.
Although vaccinations were not discussed in that paper, these new findings suggest yet another powerful reason to get your annual flu shot in September. Doing so could save your life, heart and brain! And if you are 65 or younger with risk factors for pneumonia, getting that vaccine could also be one of the easiest — and fastest — ways to protect your memory, your lungs and your arteries!
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