Israel reports 4 hospitalized among 18,000 smallpox immunizations
Data may foreshadow more adverse smallpox reactions in U.S.
In emerging findings that will fuel more debate about immunizing U.S. health care workers for smallpox, a similar program in Israel has resulted in four hospitalizations — including the immunocompromised wife of a vaccinee, Bioterrorism Watch has learned.
No deaths have been reported after immunizing some 18,000 health care workers in Israel, but the hospitalizations suggest the rate of serious adverse reactions may be somewhat higher than historically seen in the smallpox medical literature. Is the glass half empty or half full?
"I don’t want to get superstitious; I may get the next telephone call that we have another side effect," says Ido Hadari, spokesman for the Israeli Ministry of Health in Jerusalem. "But considering what is known in the medical literature, these 18,000 are getting very well right now without side effects or problems. We are very [thorough] in selecting those to receive vaccination."
Currently, about 15% of health care workers are being screened out due to contraindications. For the most part, those workers who have been immunized have not missed work in Israeli hospitals, he says. "After they get the vaccination, they get dressed and go back to their positions," he says. To some degree, the hospitalizations following immunization in Israel reflect err on the side of caution, he adds. "We have had four cases we decided to hospitalize, even though three of them were fine," Hadari adds. "One case was a person who got vaccinated and developed a slight fever and an inflammation of the muscles of the heart. But we are still checking [the link] between the [condition] he had, which can be caused by many things, and getting the vaccination."
The most serious adverse reaction was in the wife of a health care worker who had recently been vaccinated. "If the husband had read the [informed consent] sheet, he would have known he shouldn’t have gotten vaccinated," he explains. "He is living in the same home with a person who suffers from a weakened immune system and takes steroids. She developed general vaccinia, and her condition was not good." However, the woman responded to treatment with vaccine immune globulin and has completely recovered, he says.
Still, the fact that four people were hospitalized — despite a screening effort that included selecting those previously immunized for smallpox — suggest the U.S. health care workers will see more serious adverse reactions than recorded in the medical literature.
"The Israelis were also using a milder vaccine," says Brian L. Strom, MD, MPH, director of the Center for Clinical Epidemiology and Biostatistics at the University of Pennsylvania School of Medicine in Philadelphia. "I would be very surprised if we did not see higher rates than the published rates."
Historic estimates based on passive reports
The typically discussed risk of one death per million and some 40 serious reactions is based on old passive surveillance systems, says Strom, chairman of an Institute of Medicine committee that recently issued a cautionary report on the Centers for Disease Control and Prevention’s (CDC) smallpox immunization plan. "They are almost surely underestimates of the real risk," he says.
The CDC is sending a team to Israel to take a firsthand look at its smallpox immunization program. In the most recent information posted on its web sites, the CDC estimates that for every million people vaccinated, 1,000 will have nonlife-threatening, serious reactions; between 14 and 52 will have life-threatening reactions; and one or two will die. A rough extrapolation of the initial Israeli report projects out to 150 to 200 hospitalizations per million vaccinations.
According to the CDC, the statistical information about smallpox vaccine adverse reactions is based on data from studies conducted in 1968. Adverse event rates in the United States today may be higher because more people are immune-suppressed from cancer, cancer therapy, organ transplants, and HIV. On the other hand, the patient outcomes following adverse reactions may be better because of advances in medical care. The CDC has created an algorithm to track adverse reactions and distinguish those that are mild from those that are life-threatening. (See algorithm.)
Given the possibility of severe reactions, the programs in both Israel and the United States are voluntary. As has been seen stateside, there has been reluctance among Israeli health care workers to be vaccinated since the program began last August. "We have 150,000 people working in health care," Hadari says. "We expected to get more compliance from the health workers, and it was a big disappointment for us."
A contributing factor was that the program was launched right before national holidays in Israel, and people who planned to travel or have guests were reluctant to be immunized, he says. "Then after the holidays ended, we suffered from [poor] momentum," he adds.
Scores of U.S. hospitals similarly have opted out of the program here, but the CDC still expects to have immunized teams in thousands of facilities. As of Jan. 29, 38 states had requested a total of 195,700 doses of vaccine.
"The goal of this program is not to ensure that every hospital in the country has vaccinated employees," says Julie Gerberding, MD, MPH, director of the CDC. "The goal is to ensure that we have the public health response teams that can go out and assess initial cases and that we have health care personnel in a facility in that jurisdiction that would be able to take care of the first cases. We have 3,000-plus hospitals that have indicated that their personnel will be participating in the program. We never expected every hospital to participate, and we still remain confident that we will have the level of preparedness we need."
Connecticut takes U.S. lead
Connecticut was among the first states to join the U.S. effort, immunizing public health vaccinators in late January. They were, in turn, scheduled to offer the vaccine to hospital workers beginning Feb. 10, 2003.
"At this point, we have about 40 people who have volunteered," says Louise Dembry, MD, epidemiologist at Yale-New Haven (CT) Hospital. However, the hospital is not offering the vaccine to infection control professionals in the first round of immunizations. "We are trying to get a group of people who are willing to then become vaccinators," she says. "We didn’t include infection control or hospital epidemiology because we didn’t feel these were going to be people giving hands-on care to cases of smallpox. If there are cases of smallpox, they would probably be doing other activities related to infection control, so I excluded them as vaccinators."
The hospital will conduct daily vaccination site monitoring for immunized workers, whose "take" sites will be covered with semipermeable gauze dressing as recommended by the CDC.
"We are emphasizing the importance of hand hygiene," Dembry says. "We won’t allow people to work who can’t have the site contained by the bandage, have too much itching so that they are always touching their vaccination site, or have satellite lesions."
Regarding adverse effects and lost time, workers in the three-hospital Yale-New Haven system will be covered by workers’ compensation, she says. "We recognize at that point, it is a very individual decision that each person has to make," Dembry says. "We are not going out trying to recruit people and cajole them into being vaccinated. We are here to present what the vaccine is, what the risks are, and what the contradictions are."
(Editor’s note: For a wealth of materials on smallpox immunization programs, go to the CDC web site at www.bt.cdc.gov/agent/smallpox/index.asp.)
In emerging findings that will fuel more debate about immunizing U.S. health care workers for smallpox, a similar program in Israel has resulted in four hospitalizations including the immunocompromised wife of a vaccinee, Bioterrorism Watch has learned.
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