Two new studies: getting flu and/or pneumonia vaccines can reduce the risk of dementia.

Two new studies presented at the Alzheimer's Association's (AAIC) annual International Virtual Conference on July 27, local time, suggest that seasonal influenza vaccines and/or pneumococcal vaccines are associated with reduced risk of Alzheimer's disease.
in both studies (one for the flu vaccine and the other for pneumococcal), people who had at least one vaccine were less likely to be diagnosed with Alzheimer's in later life.
Although the two studies differ slightly, their similar conclusions suggest that vaccines may play a broader role in increasing the body's lifelong resistance to certain diseases. Richard Isaacson, a neuroscientist at weill Cornell Medical School in
, said: "This is an encouraging finding based on previous evidence that vaccination against common infectious diseases, such as influenza, is associated with a reduced risk of Alzheimer's disease and delayed onset of the disease.
"He was not involved in any of the studies.
the first study, which resulted in an exploratory analysis of millions of medical records to broadly identify factors that could affect a person's risk of diseases such as Alzheimer's.
in the initial study, Albert Amran, a medical student at the University of Texas Health Science Center, observed that the flu vaccine was associated with a lower incidence.
Amran then looked for the relationship among 9,066 people over the age of 60, comparing the diagnosis of Alzheimer's disease in people who had been vaccinated after the age of 60 and those who had not.
each group included almost equal groups of people with potentially mixed risk factors such as smoking status, obesity, diabetes, cardiovascular disease, education, age and income. "We found that more vaccinations mean less Alzheimer's disease, " said
Amran.
people who had been vaccinated against the seasonal flu vaccine at least once after age 60 were 17 percent less likely to be diagnosed with Alzheimer's, while those who received the flu vaccine each year were 13 percent less likely to be diagnosed. The earlier the
get the flu vaccine after age 60, the more effective it is.
While Amran is heartened by these results, he adds that a comprehensive assessment of the potential benefits of vaccination needs to be quantified in more depth.
second study by researchers at Duke University and the University of North Carolina.
they looked at the relationship between the pneumococcal vaccine (and/or with the flu vaccine) and the risk of Alzheimer's disease.
the team analyzed the medical records of 5,146 people over the age of 65 and excluded factors such as gender, race, education and smoking.
others involved in the study also had a known genetic risk factor for Alzheimer's disease, the rs2075650 G allele in the TOMM40 gene, which is associated with the permeability of the blood-brain barrier that protects the brain from infection.
study co-author Svetlana Ukraintseva, a geneticist at Duke University, reported that people who were vaccinated against pneumococcal disease between the ages of 65 and 75 were associated with a 25 to 30 percent reduction in the risk of Alzheimer's disease.
For those who don't carry the rs2075650 G allele, their risk of getting vaccinated is reduced by 40 percent.
pneumococcal vaccine appears to have a protective effect on older people.
both teams are trying to determine the biological mechanisms they found, but they do have some initial ideas. "Because many different types of pathogens are associated with Alzheimer's disease, including viruses, bacteria and fungi, vaccines can protect people from infection in their lives," said
Ukraintseva.
some vaccines have shown non-target effects that are beneficial to health beyond their protection against specific diseases.
this may be because they can improve immunity on a wide range of areas.
the brain's immune system has long been associated with the onset of Alzheimer's disease, specifically, disorders of small glial cells and the overall immune system of the brain may thus become an important intermediary for cognitive decline.
"Similarly, because both influenza and pneumonia affect the brain, reducing exposure to them over a lifetime can keep the immune system strong for longer. Maria Carrillo, chief scientific officer of the Alzheimer's Society at the
, who was not involved in the two studies, said: "Every time you get one of these diseases, your memory and thinking are challenged.
" Dallas Anderson, a neuroepidemiologist at the U.S. National Geriatrics Institute who was not involved in the two studies, agrees that there may be other health effects besides preventing influenza.
but he urged the need for further research.
while both teams are trying to control the mix, there may be other commonalities between vaccinated people to explain the results.
he said: "Observational studies can never clearly show that flu vaccination can prevent Alzheimer's or dementia.
evidence is only suggestive at best.
"