JAMA editorial discusses role of influenza and pneumonia vaccines
in reducing risks of heart attack, stroke
Based on research at Texas Heart Institute at St. Luke's Episcopal
Houston, Texas (May 4, 2010)
– Physician-scientists at the Texas Heart Institute at St. Luke's Episcopal Hospital (THI at St. Luke's) are publishing an editorial this week in the
Journal of the American Medical Association that warns against drawing too-broad conclusions one way or another about whether pneumonia vaccines reduce the risk of heart attack or stroke in high-risk patients.
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Dr. Mohammad Madjid
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Meanwhile, physicians should continue to increase the number of patients who receive the vaccine, the authors urge.
The subject, as the editorial points out, is a matter of much debate and some "myth" within the medical community. Determining the answer has "immense clinical implications," the authors write, because it offers a potential way for doctors to prevent some heart attacks and strokes by preventing some respiratory infections that can trigger the attacks.
The editorial is authored by Dr. Mohammad Madjid, a THI senior research scientist, and Dr. Daniel M. Musher, with the Baylor College of Medicine in Houston.
What is known is that some respiratory infections brought on by pneumonia and, more frequently by influenza, in high-risk patients such as the elderly can trigger "exaggerated inflammation" which can cascade within the body and bring on heart attacks (Myocardial Infarctions) or strokes.
Dr. Madjid, along with Dr. S. Ward Casscells, has conducted significant research at THI at St. Luke's which has demonstrated this cascade process with regard to infections caused by the flu. That research also concluded that cardiac patients who receive the influenza vaccine significantly lessen their chance of suffering a heart attack, later confirmed by other groups. These studies led to official recommendation by the American Heart Association and American College of Cardiology to vaccinate subjects with coronary artery disease against influenza. But, such definitive research is not yet available with regard to the pneumonia vaccine.
The JAMA editorial cites one study that concluded there is no association between pneumonia vaccine and the risk of heart attack or stroke. But, the editorial authors point out a number of questions about that study and cite other research that indicates the opposite.
What is needed, writes Madjid, is more rigorous examination of the questions and of other interventions, such as whether early use of antibiotics and anti-inflammatory drugs, such as statins, could offer additional protection.
In the meantime, the editorial advises, other studies have shown that the pneumonia vaccine provides significant protection against pneumonia itself. The research also shows that the vaccine is associated with a reduction in the risk of pneumococcal respiratory infection by 30-60 percent.
"The core question is whether the vaccine can be shown definitively to reduce cardiovascular risk," said Madjid. "The answer isn't yet totally clear, but what is clear are the benefits of vaccination and we should keep vaccinating. If a cardioprotective effect is ever proven for pneumonia vaccination, it will be an added bonus which will be welcomed by the medical community."
The JAMA editorial concludes: "Until rigorous data from clinical trials are available …, physicians should strictly adhere to available guidelines for optimizing vaccination rates in recommended target groups, because the rates are still far from optimal."
See also on this website:
Research shows flu can trigger heart attacks.
For media inquiries please contact:
Texas Heart Institute
Frank Michel ♦ 713-218-2210 or 832-355-9246
Email: fmichel@heart.thi.tmc.edu
For THI and St. Luke's media profiles, see Public Affairs.
