ATLANTA -- The Centers for Disease Control and Prevention (CDC) today took the precautionary step of adding a temporary medical deferral to the smallpox vaccination program for persons who have been diagnosed with heart disease. The CDC is investigating whether there is any association between smallpox vaccination and reports of heart problems in seven healthcare workers who have been vaccinated.
CDC added the temporary measure to the existing list of deferral criteria based on information from its real-time monitoring system, which showed a small number of heart-related incidents among health care workers following smallpox vaccination. It is not clear whether this number is greater than would be expected normally in this population, CDC scientists said.
"We promised to closely monitor this program and to put safety first, so we are exercising exceptional caution," said Julie Gerberding, MD, CDC director. "If our investigation shows this precautionary measure should become permanent or the need for other changes or enhancements in the civilian smallpox vaccination program, we will take immediate action. We continue to believe that it is important and necessary to vaccinate health care workers to prepare our nation in the event we have to respond to a smallpox outbreak," Gerberding said.
CDC is recommending that persons with known cardiac disease -- such as cardiomyopathy, previous heart attack, history of angina, or other evidence of coronary artery disease -- be temporarily deferred from receiving smallpox vaccination. CDC will provide states with simple questions about heart problems to use in screening people volunteering for smallpox vaccination.
In pursuing its promise of safety, last week CDC asked the Advisory Committee on Immunization Practices' (ACIP) Smallpox Vaccine Safety Review Board to examine reports of heart-related adverse events occurring in connection with the smallpox vaccination program. CDC is also beginning research projects aimed at identifying and understanding any associations that may exist between smallpox vaccine and heart-related problems.
"A major part of our monitoring program involves regularly sharing information about adverse events with experts such as those on the ACIP. They can help assess whether the smallpox vaccine is, indeed, associated with the medical conditions described in the adverse event reports," said Walter Orenstein, MD, director of CDC's National Immunization Program.
CDC has received several reports of heart-related problems among the 25,645 people who have been vaccinated in the civilian program. The seven cases prompting today's precautionary action include three cases of myocardial infarction (heart attack), one of which resulted in death; two cases of angina (chest pain); and two cases of myopericarditis (inflammation of the heart muscle or sac surrounding the heart). In each case the individual's medical history, including risk factors for heart disease, is being studied.
Cases of heart inflammation following smallpox vaccination were reported in the 1960s and 1970s. However, the information from these reports does not provide any information about the types of people who may be at higher risk for heart-related problems following smallpox vaccination.