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Smallpox Vaccination Programs Adopt Cardiac Precaution

Cheryl Thompson

Persons who have been diagnosed with a heart condition or who have at least three major risk factors for cardiac disease should not be vaccinated against smallpox during the country's buildup of smallpox-response teams, the Centers for Disease Control and Prevention (CDC) announced yesterday.

The newly revised AHFS Drug Information monograph (PDF) on smallpox vaccine can be obtained from the ASHP Emergency Preparedness–Counterterrorism Resource Center.

The decision solidified a temporary exclusion that CDC had announced Thursday, one day after the second civilian died of a myocardial infarction in the first few weeks after vaccination. At the time, CDC had decided to temporarily exclude persons with a history of heart disease. The Department of Defense made a similar decision for the military's smallpox vaccination program, which reported one death from myocardial infarction. 

Both of the civilians who died, CDC reported, were women in their 50s who had had hypertension and were smokers. One of them also had hypercholesterolemia, while the other had undergone cardiac catheterization at some time in the past. A total of seven civilian health care or public health workers have had cardiac-related problems, such as myocarditis or angina, after smallpox vaccination.

The man who died of a myocardial infarction after vaccination through the military program was a 55-year-old National Guard soldier with cardiac disease, the Defense Department reported. Fourteen cases of myocarditis or pericarditis have been diagnosed among military personnel, all in persons whose recent vaccination was their first exposure to smallpox vaccine.

The unexpected occurrence of cardiac problems in health care or public health workers fairly soon after smallpox vaccination prompted CDC to turn to its Advisory Committee on Immunization Practices (ACIP) for recommendations on how to proceed.

ACIP met Friday by conference call and, CDC said, recommended that, if there is no evidence of an actual smallpox case, the vaccine should not be administered to persons with known underlying heart disease, even if symptoms are lacking, or to persons with three or more major cardiac risk factors. These recommendations were accepted by CDC, which also decided to continue the smallpox vaccination program for civilian volunteers.

CDC revised the smallpox-vaccine fact sheet for recent vaccinees (PDF) to inform them of the need to see a health care provider immediately if they have chest pain, shortness of breath, or another symptom of cardiac disease.

The CDC fact sheet for potential vaccinees (PDF) during the current vaccination program was revised to tell them not to be vaccinated if they have previously had a myocardial infarction; have been diagnosed with angina pectoris, congestive heart failure, cardiomyopathy, a stroke, or a transient ischemic attack; have chest pain or shortness of breath when they engage in a physical activity; or are under a physician's care for any heart condition. Also, persons should not be vaccinated if they have three or more of the following risk factors for cardiac disease: hypertension, hypercholesterolemia, diabetes mellitus, a parent or sibling who had a heart condition before age 50, and are a cigarette smoker.

CDC reported that, as of March 21, smallpox vaccine had been administered to 25,645 civilians, 0.03 percent of whom later had a cardiac problem.

More than 350,000 military personnel have been vaccinated as of March 31, the Defense Department reported. The percentage who later had a cardiac problem was less than 0.004.

About the same time that CDC was rethinking its exclusion criteria for the current smallpox vaccination program, the Institute of Medicine released its second assessment (PDF) of the program's implementation. The assessment called on CDC to stop measuring the nation's preparedness for a smallpox outbreak solely in terms of the number of persons vaccinated and to start studying the ability of communities' public health medical personnel and emergency responders to coordinate their efforts once a case is discovered.