National Smallpox Response Plan Updated
The response plan provides information on mounting a mass vaccination campaign to protect large segments of the U.S. population if smallpox is detected in the community. Walter Orenstein, director of the Centers for Disease Control and Prevention (CDC) National Immunization Program, said during a Sept. 23 media briefing that the mass vaccination plan would supplement the ring vaccination strategy once used to combat naturally occurring outbreaks of smallpox.
"The decision to do mass vaccination will be dependent upon an assessment of the magnitude of the attack, the potential duration of the attack, and the mode of the attack," he said.
Implementing the Plan
The decision of when and how to implement the nation's smallpox response plan would be made by the president and the secretary of the Health and Human Services Department (HHS), said Jerome Hauer, HHS acting assistant secretary for Public Health Emergency Preparedness.
"Certainly, if we had one case of smallpox anywhere in the United States, we would begin vaccination right away," Hauer said today during an appearance on C-SPAN.
Hauer said that a debate exists over whether initially to limit the response to ring vaccination, which focuses on vaccinating people who have come in contact with someone who has smallpox, or to start mass vaccination of the general public.
"In general, what we would do is start with ring [vaccination]," Hauer said. "Depending on how many people we see who have potentially been exposed or how many other sentinel cases there are, we might start mass vaccination quite early, rather than just relying on ring vaccination."
Hauer said that if 50 to 100 smallpox cases were detected in one area, ring vaccination would be used to protect the people who were exposed to those with the disease. "People that were exposed to primary contacts would have a high likelihood of getting the disease," he said. "If you give them the vaccine, you can prevent them from dying from smallpox. And if you give it early enough, you might actually prevent them from getting the disease."
In this hypothetical example, Hauer said that mass vaccination would get under way while ring vaccination was taking place as part of a "combined strategy" to protect the public.
Hauer noted that the current supply of smallpox vaccine is large enough to meet the country's needs, although some products may require dilution during an epidemic. "We have enough vaccine in the United States, should we have an outbreak, to protect everybody in the country," he said.
Once the decision is made to begin mass vaccination, the smallpox vaccine would be administered at predesignated local vaccination clinicseach of which would need pharmacists, pharmacy technicians, or other staff to prepare vaccine doses. In a model vaccination clinic described in the plan, two pharmacy workers would be needed during each of two daily eight-hour shifts to prepare enough vaccine for 1 million people in a 10-day period.
The document estimates that as many as 4,600 health care workers and auxiliary staff would be needed to vaccinate 1 million people in a week. Additional health care workers and support staff would be needed to care for the victims of a smallpox outbreak. Separate facilities would be needed for vaccination of the general public and for vaccination and treatment of people who have smallpox or are likely to be infected with the virus.
"The purpose of these guidelines is to provide states with important information they can use to effectively and rapidly respond to a smallpox outbreak," said Joseph Henderson, associate director for terrorism preparedness at CDC. Henderson noted that the response plan is the third revision of a document released last November, and he said that CDC will continue to update the plan.
According to the planning document, the federal government may mobilize the National Pharmaceutical Stockpile to ship initial supplies of smallpox vaccine to clinics in "VaxiCool" units. Made by Ohio-headquartered Energy Storage Technologies Inc., each VaxiCool unit can hold up to 300 multidose vials of smallpox vaccine. When connected to a power source, the units can be used to store refrigerated or frozen vaccine.
Subsequent vaccine supplies from the stockpile would be shipped in insulated containers and require transfer to an appropriate storage unit at the vaccination clinic. According to the plan, the federal government is prepared to ship 75 million doses of vaccine to clinics on the first day that vaccination begins. Up to 280 million additional doses could be shipped from the stockpile within one week.
Because the nation's smallpox vaccine supply consists of products with different formulations, storage conditions, and reconstitution requirements, the response plan advises vaccination clinic staff to review the particulars of the vaccine used at the site before working with the product.
Vaccination clinic staff should receive a smallpox shot before starting work at the site. The response plan notes that health care workers can begin their clinic duties right after receiving the shot if the clinic vaccinates only asymptomatic people who have not been exposed to the virus.
Ideally, health care workers who may come in contact with people who have smallpox would be immunized before an outbreak occurs. Orenstein said that CDC is awaiting the Bush administration's decision on a policy for "pre-attack" vaccination of health care workers and other first responders.
The use of the vaccine either before or after a release of the virus is complicated by the fact that smallpox vaccine is considered an experimental drug that must be administered under an investigational new drug protocol. Included in the plan are sample informed-consent and record-keeping forms to use when administering the smallpox vaccine as an investigational product.
The plan states that two intravenously administered drugsvaccinia immune globulin (VIG) and cidofovirwould also be available from CDC as investigational products during a smallpox outbreak. According to the plan, CDC would supply the drugs to clinics for the treatment of eczema vaccinatum, a known complication of smallpox vaccination.
The Food and Drug Administration approved an injectable formulation of cidofovir in 1996 for the treatment of cytomegalovirus retinitis in patients with AIDS. An orally administered derivative of the drug has shown promise in animal studies for the prevention and treatment of smallpox, but the product is not approved for use in humans and would not be shipped to clinics.