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Smallpox Vaccine Has "No Serious Side Effects," Military Study Concludes

By Sgt. 1st Class Doug Sample
American Forces Press Service

WASHINGTON, June 25, 2003 – Mass smallpox vaccinations can be conducted safely with "very low" rates of serious adverse effects, the Defense Department's senior medical official said today.

And the military will continue with its vaccination program because the smallpox bioterror threat remains, said Dr. William Winkenwerder, assistant secretary of defense for health affairs, during a press briefing at the National Press Club.

"Although we are no longer vaccinating service members at the rate we witnessed earlier in the program, we continue to vaccinate those who are serving or who soon will be serving in high-risk areas," he noted.

"Our experience demonstrates that on a large scale the smallpox vaccination program can be conducted safely," Winkenwerder said.

DoD's top doctor pointed out that there are risks associated with the smallpox vaccination, even though significant side effects are rare and death, very rare. But, he added, "Our experience is that it is possible to reduce those risks associated with the vaccine."

According to information from the five and a half-month military study, DoD administered 450,293 smallpox vaccinations, including more than 50,000 per week at the peak of the military vaccination program.

The study began Dec. 13, 2002, the day after President Bush announced the plan to vaccinate the military, and ended May 28, 2003.

During that period, the military began vaccinating selected military personnel in a national program of preparedness against the use of smallpox as a biological weapon.

Army Col. John D. Grabenstein, deputy director for clinical operations at the Military Vaccine Agency, said the study proved that the vaccine was administered without many adverse reactions, such as skin irritation and blister rashes, or risks associated with the vaccine.

Grabenstein, who along with Winkenwerder co-authored a report on the vaccination study, said that adverse incidents were not as apparent as historical data would suggest.

"Itching at the vaccination site was reported by about 60 percent of those vaccinated," Grabenstein said. In addition, he said that cases of "blister rashes were mild and that they were treated on an outpatient basis.

He also noted that only 3 percent needed to take sick leave after being vaccinated. That leave lasted roughly a day and a half, he said.

Winkenwerder said key elements of keeping risks to a minimum during the vaccination program include comprehensive training of medical staff; education and careful screening of service members to be vaccinated; close monitoring following vaccination; and early intervention when adverse events occur.

He noted one very important finding in the study: no cases of transmission of vaccine virus from the health care worker to the patient.

But there were some concerns about the study. Winkenwerder said acute myopericarditis - inflammation of the membrane covering the heart - occurred in a small number of service members who received the vaccine: about 1 in 12,000, or 37, people.

"All of these individuals have recovered or they are recovering and we will continue to follow them," he said.

Grabenstein also refuted media accounts of the vaccine causing heart attacks in military personnel.

"We have had several heart attacks among smallpox vaccines, but no more than we have had among a similar amount of unvaccinated people," he said. "So our conclusion is that heart attacks and small pox vaccination are unrelated," he said.

Winkenwerder said that information learned from the study will provide the American medical community and public with "current, factual information that will be useful as the U.S. moves forward with its vaccination program."

The study's results were reported on the Journal of the American Medical Association's Web site at www.jama.ama-assn.org.

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