Time for a pause
Medicine is a humbling profession, notorious for its surprises. The most recent example is the smallpox vaccination program for military and hospital workers, which took us off guard with more than 20 cardiac complications, including three heart attack deaths. These have been the only deaths so far among 365,000 in the military and more than 30,000 civilians.
The government anticipated and largely prevented the well-documented skin reactions and rare cases of encephalitis. These side effects were expected to cause 1 death per million. Government scientists rightly excluded anyone with skin and immune system conditions known to be at highest risk. But heart events weren't even on the radar screen. These unforeseen complications should make us hit the pause button now.
Although the Centers for Disease Control and Prevention began exempting those with heart risks, it has continued vaccination. Nonetheless, 16 states have temporarily suspended their programs. Wise moves, provided it's a time to refashion the effort. Facing the prospect of mass vaccinations in the event of a bioterror event--the only reason for the present program--we are doubly obliged to understand these heart reactions and introduce rigorous safety monitoring.
The heart complications are of two kinds: heart inflammation in those with seemingly normal hearts and heart attacks in those with pre-existing hardening of the arteries. In retrospect, both have been linked to smallpox vaccination. Old medical reports from Europe and Australia describe occasional cases of inflammation, heart failure, coronary thrombosis, and heart attacks after smallpox vaccination. It's true that these problems were almost never seen here in previous mass inoculations, but that difference is very likely attributable to the milder strain of live vaccinia virus (a cousin to smallpox) that was used in the United States and Canada. This raises an obvious question: Did we miss the heart problems, or has the vaccine morphed into a different and more unfriendly strain?
Tip of the iceberg? Whichever it may be, we have now seen 17 young people with previously normal hearts develop dangerous inflammations--known technically as myocarditis, involving the heart muscle, and pericarditis, the sac around the heart. Some even experienced severe heart failure, though happily all recovered. But these early numbers translate to roughly 1 in 20,000, which means thousands would fall ill were a mass vaccination undertaken. What scientists now have to determine is whether this is just the tip of the iceberg.
Viral infection of the heart is most often symptom free. In a Finnish study back in 1978, 3 percent of those vaccinated against smallpox had "silent" myocarditis. We know now that such inflammation can lead to heart failure years later. Given that risk, we're obliged to follow those who have been ill and, additionally, to find out just how common myocarditis really is. This can be done only by evaluating the next several thousand volunteers who step up for vaccination with simple but costly heart testing, including EKG, sonogram, and blood tests. Such testing is not currently done.
The five heart attacks and several cases of angina (heart pain from sudden lack of blood to the heart) pose an even bigger puzzle. Since those afflicted were mostly middle-aged with hypertension and pre-existing coronary disease, it's easy to say, as many are, that these events are simply a matter of chance. But we don't know that, and we'd better explore the alternative.
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