Studies Show Influenza and Pneumonia Vaccines May Reduce Risk of Developing Alzheimer’s

Two studies show the influenza (flu) and pneumonia vaccines lessen the risk of developing Alzheimer’s disease (AD) in the future.

The first study examined a large American health record data set of more than 9,000 patients over age 60 years and found having one flu vaccination was associated with a 17 percent reduction in Alzheimer’s incidence. Further, those vaccinated more than once over the years saw an additional 13 percent reduction in incidence. The protective association appeared to be strongest for those who received their first vaccine at a younger age, for example at age 60 years versus 70 years.

“There has been a concern in the medical community that many sources of inflammation such as urinary tract infections worsen the course of patients with Alzheimer’s disease,” said Albert Amran, a fourth-year medical student with McGovern Medical School at The University of Texas Health Science Center at Houston. “Hence, we have been worried that vaccinations, a form of inflammation, could also worsen the course of AD.”

The second study, which examined the associations between pneumococcal vaccine with and without an accompanying flu shot and the risk of AD, analyzed more than 5,000 people over 65 years who were participating in the Cardiovascular Health Study, a long-term government funded examination of risk factors for cardiovascular disease. Some participants had a known genetic risk factor for AD: the rs2075650 G allele in the TOMM40 gene, which has also been linked to a higher risk for lifetime depression. The researchers found that getting a pneumococcal vaccine between the ages of 65 years and 75 years reduced risk of developing AD by 25 percent to 30 percent after adjusting for sex, race, birth cohort, education, smoking and genetic risk factors. However, the largest reduction in the risk of AD — up to 40 percent — was seen among people vaccinated against pneumonia who didn’t have the risk gene.

“This is an encouraging finding that builds upon prior evidence that vaccination against common infectious diseases — such as the flu — is associated with a reduced risk for Alzheimer’s and a delay in disease onset,” said neurologist Richard Isaacson, founder of the Alzheimer’s Prevention Clinic at NewYork-Presbyterian and Weill Cornell Medical Center. “Regular use of the flu vaccine, especially starting at an early age, may help prevent viral infections that could cause cascading effects on the immune system and inflammatory pathways. These viral infections may trigger Alzheimer’s-related cognitive decline.”