(LifeWire) - If you're at risk for a heart attack (or myocardial infarction), getting a pneumonia shot could cut that risk in half, according to a 2008 study conducted by Canadian researchers.
The study in the Canadian Medical Association Journal focused on patients with risk factors for heart disease, such as high blood pressure or diabetes. Furthermore, the study reports indicated that pneumonia shots appeared to offer 2 years of heart protection.
It's not clear how the vaccine does helps, but doctors know that pneumonia affects the cardiovascular system in at least two ways: It reduces lung capacity, which reduces oxygen in the blood, increasing the heart's workload, and it inflames the coronary arteries.
The key may lie in countering the arterial inflammation that accompanies pneumonia. Inflammation is linked with atherosclerosis (the buildup of fatty plaques in the arteries), although the connections still are not fully understood. Atherosclerosis is a major risk factor for heart attack.
Researchers have demonstrated that the pneumonia vaccine reduces atherosclerosis in mice; however, the results haven't been replicated in humans.
Scientists note that there could be other explanations. People who get pneumonia shots might be less likely to smoke -- or more health conscious, in general -- which could account for some of their reduced incidence of heart attack.
Pneumonia shots are considered safe and are available at doctors' offices year-round. Mild side effects may include swelling or soreness at the injection site. For the majority of people, one shot provides a lifetime immunity, whereas others may need a booster every 5 years. Medicare and Medicaid cover the cost of these vaccines.
"Avoiding Flu and Pneumonia." americanheart.org. 13 Dec. 2007. American Heart Association. 2 Dec. 2008 <http://www.americanheart.org/presenter.jhtml?identifier=351>.
Lamontagne, François, et al. "Pneumococcal Vaccination and Risk of Myocardial Infarction." Canadian Medical Association Journal 179:8(2008):773-7. 2 Dec. 2008 <http://www.cmaj.ca/cgi/content/full/179/8/773>.
Musher, Daniel M., Adriana M. Rueda, Anjum S. Kaka, and Sulaiman M. Mapara. "The Association Between Pneumococcal Pneumonia and Acute Cardiac Events." Clinical Infectious Diseases 45:2(2007): 158-65. 2 Dec. 2008 <http://www.journals.uchicago.edu/doi/full/10.1086/518849>.
"Pneumococcal Vaccine Publications (for Adults)." cdc.gov. 6 Feb. 2007. Centers for Disease Control. 2 Dec. 2008 <http://www.cdc.gov/vaccines/vpd-vac/pneumo/vac-pneumo-pubs.htm>.