Flu and pneumonia shots do more than their intended purpose as they also lower risk of Alzheimer's disease, studies say.

Getting a flu or pneumonia shot lowers risk of a nasty infection, and unknowingly, until recently that is, it also minimises the risk of developing Alzheimer's disease later. This hypothesis was based on two separate studies presented Monday, at the Alzheimer's Association International Conference.

According to Dr Richard Isaacson, the optimistic finding was built upon past evidence that vaccinations against some of the most common infectious diseases like flu is linked to a reduced Alzheimer's risk and delays its onset. Dr Isaacson, who was not involved in the study, is the founder of the Alzheimer's Prevention Clinic at the NewYork-Presbyterian and Weill Cornell Medical Center, CNN Health reports. "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," he said.

However, some experts say there is a need to conduct more studies to establish the link between getting those vaccines and the lowered risk. At present, Alzheimer's disease (AD) does not have any cure. But, some studies show that giving due attention to particular key lifestyle factors like proper nutrition, sleep, and exercise, may influence the individual risk of a person. Having the vaccine falls into this category.

If just getting flu or pneumonia shots reduces Alzheimer's risk, then this is a crucial message that needs to be spread to the public, according to Maria Carrillo, the chief science officer of the Alzheimer's Association. She also oversees the many research initiatives for the organisation. "We do need more research to understand what that connection is," Carillo told CNN.

She also posed several questions as to whether the vaccine to disease effect is direct and whether such a measure is protective. She believed these are important questions since it may form part of the risk reduction strategies that are already in place, such as lowering the body mass index (BMI), watching the sugar intake, keeping an eye on high blood pressure and cholesterol levels, and exercising. "It's one of those sorts of health tips that we need to make sure that our public knows about," she added.

Getting a vaccination
Person getting a vaccination whitesession/Pixabay

AD and Influenza Vaccine

Albert Amran, a fourth-year medical student at The University of Texas Health Science Center's McGovern Medical School presented the first study. The work of his team involved examining a huge American health record data set of over 9,000 AD patients 60 years old and above.

Researchers found that getting one flu shot was linked to a 17 percent reduction in the incidence of Alzheimer's disease. Those who got the shots in more than once over several years experienced an additional reduction of 13 percent in AD incidence.

In an interview with CNN, Amran said there is concern within the medical community that most inflammation sources, like urinary tract infections, aggravate the condition of AD disease patients. "Hence, we have been worried that vaccinations, a form of inflammation, could also worsen the course of AD," he said.

Doctors, at the same time, recommend getting flu vaccinations for people with AD because the flu is usually deadly. Data from the Centers for Disease Control and Prevention show flu caused deaths of approximately 12,000 to 61,000 people each year in the US since 2010.

Amran and his team welcomed the results of the study that show flu shots reduced AD incidence. "We were very surprised, because of the concern noted above about the potential to increase AD when our statistical colleagues told us that the flu vaccination was one of the 'medications' that is so strongly associated with a lower Alzheimer's incidence," he said.

AD and Pneumonia Vaccine

The second study analysed the link between the pneumococcal vaccine, with and without a supplementary flu shot, and Alzheimer's risk. The study examined more than 5,000 people 65 years and older who were participating in the Cardiovascular Health Study, a government-funded research on cardiovascular disease risk factors. Some of the volunteers had rs2075650 G allele in the TOMM40 gene, which is a known genetic risk factor for AD. It has also been linked to an elevated risk for lifetime depression.

Researchers found that getting pneumococcal shots between 65 and 75 years old lowered the risk of Alzheimer's by around 25 to 30 percent after adjusting for birth cohort, race, sex, education, smoking, and genetic risk factors. However, the biggest reduction in Alzheimer's risk, which can be up to 40 percent, was seen among people who got pneumonia shots and did not have the risk gene.