Pneumonia vaccine may cut heart attack risk

TORONTO—Adults who have been vaccinated against a common type of bacterial pneumonia appear to have a dramatically lower risk of having a heart attack than those not given the shot in the arm, Canadian researchers have found.
The study of about 5,000 patients at risk for a heart attack raises intriguing questions about the role of infection and inflammation on the cardiovascular system, and offers another possible reason for getting vaccinated against pneumococcal pneumonia, the researchers suggest.

“We know that the pneumococcal vaccination can alter one of the complex mechanisms of atherosclerosis, one of the steps in the formation of atherosclerotic plaque,” said principal investigator Dr. Danielle Pilon of the University of Sherbrooke. “So we wanted to see if this could be replicated in clinic.
“The hypothesis was that if the vaccination can alter one of the steps in atherosclerosis formation, perhaps it could decrease the risk of heart attack. And this is what we found,” she added.
Atherosclerosis is a disease in which plaque—comprising fat, cholesterol, calcium, and other substances in the blood—builds up on the insides of the arteries. Over time, plaque hardens and clogs the arteries, which can lead to potentially fatal heart attacks or stroke.
Pilon, a specialist in internal medicine and clinical pharmacology, said vaccination was associated with a more than 50 percent decrease in the rate of heart attack following inoculation.
“We didn’t expect that much, really,” Pilon said from Sherbrooke, Que. “For our results, the effect of the vaccine was more evident after a year, but probably it could be more after two or three or five years.”
However, she warned about over-interpreting the results of the research, which compared about 1,000 patients who had suffered a heart attack with about 4,000 patients who had not had a heart attack, but were at high risk for one.
Subjects had a mean age of about 60.
“This is a case-controlled study, so we have to be very careful . . . it is still an explanatory study and the results are still to be confirmed, for sure,” she said.
Commenting on the study, Dr. Douglas Lee said the results suggest there is a strong link between pneumococcal vaccination and protection from heart attacks. But he noted there are caveats with a study of this kind, which took its patient data from hospital and other health records.
“One of them is: Is this association there? Did they detect this association because people who get vaccinated are also more likely to take other preventive measures that would also put them at lower risk for heart attack?” asked Lee, a cardiologist at Toronto’s University Health Network.
In a commentary accompanying the paper, published in this week’s issue of the Canadian Medical Association Journal, Dr. Mohammad Madjid of the Texas Heart Institute in Houston said it’s reasonable to hypothesize that the vaccination may be protective against cardiovascular events by preventing pneumonia.