To the Editor:
In your editorial with Dr. Cross in the January 2000 issue,1 you did not discuss current availability of the smallpox vaccine in the United States. Am I correct in my impression that the military has fewer than 1 million doses of smallpox vaccine and that there is no vaccine available for use in the civilian population?
On the other hand, Henderson and the WHO group developed a method to contain smallpox outbreaks without performing mass immunization in the 1970s.2 The method is to initiate intensive surveillance and isolation procedures and to vaccinate only those who had been in close contact with smallpox cases. The mass immunization approach in the 1947 New York City smallpox outbreak with more than 6 million doses of smallpox vaccine given is now considered obsolete.
Paul R. Joseph, MD
Syosset, New York
1. Cross JT Jr, Altemeier WA ffl. Skin manifestations of bioterrorism. Pediatr Ann. 2000;29:7-9.
2. Nakano JH, Jordan MC. Smallpox and other poxvirus infections. In: Hoeprich PD, Jordan MC, Ronald AR, eds. Infectious Diseases: A Treatise of Infectious Processes. Philadelphia: Lippincott; 1994:944.
Dr. Altemeier's response:
Vaccination will be a key part of the management of a smallpox bioterrorist attack, should this ever occur. The steps in controlling or reducing the epidemic would be (1) recognizing a possible case, or cases, of smallpox; (2) reporting this and isolating those exposed; (3) confirming the diagnosis; and (4) vaccinating those exposed and perhaps those who were in the area.
Dr. Joseph is correct that stocks of smallpox vaccine are limited and should be greater. Because worldwide vaccination ended more than 20 years ago, only approximately 20% of people are estimated to have protection now. The vaccine is effective when given within a couple of days of infection, and provides some protection as late as 4 or 5 days into the 12- to 14-day incubation period. However, there are only between 6 and 7 million doses of vaccine in the United States now, and these are deteriorating with time.1,2
Work is under way to build stocks of vaccine for immunization. The existing vaccine was made by scarifying and infecting the flanks and bellies of calves. The lymph was then harvested. No manufacturer today is able to use this technique, so a new vaccine, using modern tissue culture methods, is under development. It will be expensive, and it will be years before clinical trials are complete. Stocks of vaccinia immune globulin will also have to be increased to support testing and to treat those who have spreading vaccinia infections after immunization. The Department of Defense is taking the lead on this.3
1. Henderson DA. The looming threat of bioterrorism. Science. 1999;283:1279-1282.
2. Henderson DA. Smallpox: clinical and epidemiologic features. Emerg Infect Dis. 1999. Available at: www.cdc.gov/ncidod/eid/ vol5no4/contents.htm.
3. Russell PK. Vaccines in civilian defense against bioterrorism. Emerg Infect Dis. 1999. Available at: www.cdc.gov/ncidod/eid/ vol5no4/contents.htm.