Studies Examine Adverse Events in Government Smallpox Vaccine Program

A government program to inoculate first responders and other medical personnel against smallpox did not create the high level of adverse reactions that many health experts had feared, but it remains unclear why a small number of civilian participants in the program experienced serious complications including heart attacks and heart inflammation, according to two studies published Wednesday in the Journal of the American Medical Association, the Washington Post reports (Connolly, Washington Post, 12/7). Under the national smallpox vaccination program, which began in January 2003, federal health officials hoped to vaccinate about 500,000 health care workers in the first few weeks and as many as 10 million emergency personnel, police and firefighters in the second phase of the program (California Healthline, 5/16). However, only 39,000 civilian first responders have been vaccinated to date, and more than 75,000 doses of vaccine have expired and been discarded (Washington Post, 12/2).

For one study, researchers examined side effects in 37,901 civilian first responders who were immunized from January 2003 to October 2003 (AP/Washington Times, 12/7). Of those immunized, 822 experienced adverse reactions, the majority of which were cases of minor itching, pain or rash.

One hundred cases, or 12%, were considered serious, including four nonfatal heart attacks, two fatal heart attacks and 21 cases of nonfatal inflammation of the heart muscle (Washington Post, 12/7).

According to the study, it is unclear whether the heart attacks were caused by the vaccine, but the rates of inflammation were higher than those seen in earlier studies (AP/Washington Times, 12/7). For the second study, researchers examined adverse reactions in 600,000 military personnel who received vaccinations.

Complication rates were comparable to what would be expected for the group, the study found.

According to the Post, the live smallpox vaccine "has not changed since it was first developed in the late 1700s" (Washington Post, 12/2). The U.S. ended its childhood vaccination for smallpox in 1971, and the World Health Organization declared the disease eradiated in 1980.

The vaccine, called Dryvax and manufactured by Wyeth, was not associated with heart complications prior to 2003, the AP/Times reports. Following the reports of adverse cardiovascular events, U.S. health officials said that people with heart disease should not receive the vaccination (AP/Washington Times, 12/7).

The vaccination program was proposed prior to the Iraq war as a method of protecting first responder and military personnel from a biological attack (Washington Post, 12/2).

Inger Damon, an author of the JAMA study on civilian first responders, said the heart complications were "completely not anticipated" (AP/Washington Times, 12/7).

William Schaffner, a vaccine expert at Vanderbilt University Medical Center, said, "This was the safest possible vaccination program that could be undertaken with the smallpox vaccine, but, at its best, it remains a very hazardous vaccine." Schaffner added, "The reason this vaccination campaign was undertaken was spurious. It was a mirage, there was no threat of smallpox from Iraq. And that remains a powerfully sad coda to this whole episode."

William Bicknell, a former public health director in Massachusetts, said it is critical that first responders can safely treat potential smallpox cases and inoculate the general public if a biological attack occurs. However, he added, "For sure, 39,000 civilians immunized is nowhere near enough to respond adequately to a bioterrorism event."

White House spokesperson Trent Duffy said the 39,000 civilian inoculations are "a lot better than where we were three years ago." Duffy added, "We believe plans are in place to vaccinate the entire U.S. population within 10 days."

Gina Mootrey of CDC noted that none of the civilian program participants developed life-threatening rashes that were more common when the vaccine was used in the 1960s. Mootrey said that the vaccination program is still in effect, adding that it is "up to the states to determine whether they wish to have any potential response team members vaccinated" (Washington Post, 12/2).

An abstract of the first study is available online. An abstract of the second study also is available online.