Screening, Education Could Limit Health Problems Related to Smallpox Vaccine, Study Finds
By Chris Schneidmiller
Global Security Newswire
WASHINGTON - Extensive screening and education appear to have reduced the potential for serious side effects among people who were vaccinated against smallpox in recent years, according to an article published this week in the Journal of the American Medical Association (see GSN, Nov.14).
Still, the vaccine was not without risks - at least three people died shortly after receiving the shot during a U.S. Health and Human Services vaccination program and two suffered permanent disabilities. Nevertheless, researchers said the safety system set up for vaccine recipients could point the way to safeguarding patients who are exposed to the pathogen in an act of bioterrorism.
Health and Human Services between Jan. 24 and Oct. 31, 2003, administered the Dryvax smallpox vaccine to 37,901 civilian medical professionals and first responders in 55 jurisdictions, according to the article by Centers for Disease Control researcher Christine Casey and 18 colleagues. That count was far less than the millions of volunteers the Bush administration hoped to inoculate so that they could safely provide medical and emergency care following an intentional release of smallpox.
All potential volunteers received educational material that included a questionnaire that would help them determine if they had risk factors such as eczema or immune system deficiencies that could lead to health problems following vaccination.
Recipients also received instructions on proper care for the vaccine injection site and details on reporting any "adverse events" following vaccination. An adverse event is a health problem that arises following vaccination that cannot be directly connected to the treatment, the article states. An "adverse reaction" is one that is found to be caused by the shot.
There were no reports of potentially fatal adverse reactions or reactions that required treatment with the vaccinia immune globulin, the article states. "The absence . provides indirect evidence of effective vaccination screening and education, as well as attentive vaccination site care and monitoring," the article states.
"The goal of the education and the screening was to make this as safe a vaccine administration program as possible for the adverse events we know about and were able to prevent. And I would say that we succeeded in that with this program," Gina Mootrey, associate science director for the epidemiology and surveillance division of the CDC National Immunization Program, said in an interview.
Volunteers were also monitored following vaccination. State and local jurisdictions contacted the recipients within 28 days to ensure that any serious health effects had been identified, the article states.
All adverse events were to be reported to the Centers for Disease Control and to the nationwide Vaccine Adverse Event Reporting System, Mootrey said.
There were 822 reports of adverse events - 100 of which were determined to be serious. Eighty-five people required hospital care, with 10 suffering life-threatening conditions.
Two women, ages 55 and 57, suffered fatal heart attacks within four days of vaccination, while a 45-year-old man died following a heart attack 69 days after his treatment.
"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," Vanderbilt University vaccine expert William Schaffner told the Washington Post. "Eighty-five hospitalizations, two permanent disabilities, 10 life-threatening reactions and three deaths. That is not a safe vaccine."
There were a total of 203 potential cardiac events that were possibly linked to the smallpox inoculations, according to the researchers. That included 21 cases of heart inflammation and 10 "ischemic cardiac events" - heart attacks or angina. Such responses "were not anticipated based on historical data," the article states. They quickly led to increased screening in Health and Human Services and Defense Department vaccination programs of vaccinees for potential heart problems that could be exacerbated by inoculation.
No heart attacks and angina were reported after the heightened screening was instituted, the article states.
The researchers note in the article that the rate of heart events "identified in civilian vaccinees, including the incidence of sudden death, does not appear to be greater than that expected in a comparable nonvaccinated population." It remains unknown whether the vaccine actually caused the incidents.
The researchers encouraged additional study of heart and skin risk factors and development of a vaccine less likely to produce reactions as steps toward further reducing potential health effects from the treatment.
Mootrey said the safety system used in the Health and Human Services program could be used in a mass, rapid vaccination effort in preparation for or in the wake of a bioterror incident. The educational material is available and the reporting system operating, she said.
"Our understanding of the adverse events that was gained in this small program would be readily available," she said. "We wouldn't have to learn it again."
Neurologic Events
A separate study published this week in the Journal reported limited neurologic adverse events connected to the smallpox vaccine.
The Defense and Health and Human Services departments vaccinated 665,000 people from 2002 to 2004. Subsequently, there were 214 reports of neurologic problems potentially linked to the shot. The most common complaint was headaches, with 95 cases, the article states.
There were eight seizures, which resulted in one death. Also reported were 13 cases of suspected meningitis, three incidents of suspected encephalitis and 11 cases of Bell palsy. Twenty-seven of the 39 serious events occurred in first-time vaccines, and 37 of the cases were reported within 12 days of vaccination. The events "occurred in accordance with expected ranges," according to the article.
