Smallpox and bioterrorism

The threat of smallpox as a biological weapon requires that the dental profession be prepared.

The threat of smallpox as a biological weapon requires that the dental profession be prepared.

During my years as the only dentist at the Centers for Disease Control and Prevention (CDC), outbreak investigations were a routine part of life for me, as well as my co-workers. Some of us investigated outbreaks of hepatitis B, hepatitis C, and drug-resistant tuberculosis in hospitals and health-care facilities. I would train CDC's disease detectives, known as the Epidemic Intelligence Service (EIS). When I supervised up to 18 EIS Officers, I taught these young people to perform disease-outbreak investigations as part of their two-year EIS training.

The reality of disease outbreaks was a routine part of our work. An outbreak of TB in a dental office was never published in the Morbidity and Mortality Weekly Report, because state health officers were concerned about the potential impact on a small community. One of my friends was part of the last team to go into Africa on Ebola virus outbreaks with the World Health Organization and the Belgium Institute for Tropical Medicine. My colleague, Fitzgerald, told stories about his role in the eradication of smallpox. He wore a lion's head mask and ran through villages in Indonesia seeking to attract the villagers to talk about whether they had seen people with smallpox. We patted ourselves on the backs and pointed to the eradication of smallpox, along with community water fluoridation, as a key public-health achievement of the last century.

Unfortunately, the reality of life after 9/11 has changed our perspectives, now with the threat of smallpox as a biological weapon. While this threat cannot be quantified, President Bush announced plans in December 2001 to vaccinate key military, health, and emergency workers against smallpox. For important information, visit the Web site agent/smallpox/training/webcast/dec2002/ index.asp. Plans to vaccinate dental workers have not been announced, but an upcoming conference may answer key questions relating to biologic and chemical events. (See www.ada. org/prof/events/adaevent/bioterror/index.html and 1118dis.html.)

Smallpox is caused by a virus called variola (Variola major virus), which spreads from person to person through prolonged close contact. Smallpox can cause a severe rash covering the whole body that can leave permanent scars, high fever, severe headache, or backache. Smallpox kills about 30 percent of the people it infects — about three out of 10 infected people.

In the United States, routine vaccination against smallpox ended around 1972. In May 1980, the World Health Organization declared the global eradication of smallpox as a naturally occurring disease and recommended that all countries cease vaccination, with some military vaccination continuing. President Bush's plans are underway to provide vaccinations for our 5 million health-care workers, which include dental team members. Initial plans include voluntary vaccination for about 100 people from each of the 5,100 hospitals in the United States, for a total of 500,000 people.

The smallpox vaccine has numerous side effects. Estimates for side effects are between 14 and 52 per million vaccinations given, with death occurring in one to three people. Vaccinations may be effective within three to four days of exposure and can prevent or decrease the severity of disease. People who are immunocompromised or who have eczema or dermatitis should not be vaccinated. For a complete listing of contraindications of vaccines, visit the CDC's Web site at vaccine/reactions/default.htm. Please note that pregnancy is a contraindication. For continuing education, visit poxvaccine/reactions/cont_edu.html.

Unlike other current immunizations, smallpox vaccination is characterized by a virus that propagates in the skin and can potentially contaminate the vaccinee's hands or the skin and mucosa of others with whom the vaccinee comes into contact. It is important to prevent dissemination of the vaccinia virus from the vaccination site to other parts of the vaccinee's body or to others. This may be important if you are treating someone who was recently vaccinated, because recipients can accidentally transmit vaccinia to others. Vaccine sites should be covered with a bandage to help prevent transmission. Unfortunately, disease- outbreak investigations are not a routine part of dental epidemiology or other specialty training.

Here are some guidelines:

  1. If you notice increases in sudden last-minute cancellations among patients, or unusual illnesses, symptoms or diseases, consider reporting them to the appropriate state and local health authorities or to local police and law-enforcement agencies. Listings can be found at state health sites at To locate local health officials, visit Communication systems, including 24/7 phone service, became available within the last year for most state and local public-health officials. Verify numbers before an emergency occurs and post them in a prominent area in your office. Call if you believe a biologic attack has occurred or is occurring.
  2. If you notice a patient with an unusual rash or outbreak, be sure that you and your dental team use the universal precautions recommended for treatment of all patients. Hand hygiene is the single most important precaution (see
  3. Do not attempt to treat patients with infectious agents, but instead refer them to infectious-disease specialists. Infectious-disease physicians are reliable community resources for suspicious agents. The Infectious Disease Society of America ( also is a resource for more information with a listing of local physicians.
  4. Educate yourself about the various biologic agents. Likely agents may include bacillus anthacis (anthrax), Yersinia pestis (pneumonic plague), Clostridium botulinum (Botulinum toxin), and others. (See Chin J. Control of Communicable Diseases Manual. 2000. Washington DC: American Public Health Association.)

Other resources include the following:

  • Henderson DA, et al. Smallpox as a biological weapon. JAMA. 1999; 281:2127-2137.
  • Ingelsby TV, et al. Anthrax as a biological weapon. JAMA. 1999; 281:1735-1745.
  • Ingelsby TV, et al. Plague as a biological weapon. JAMA. 2000; 283:2281-2290.

For questions about smallpox, visit www.cdc. gov/smallpox, or call the CDC National Immunization Information Hotline at (800) 232-2522 (English) or (800) 232-0233 (Español). The phone number for the CDC Emergency Response Hotline (24 hours) is (770) 488-7100. For program questions, call (404) 639-0385. For information on other biologic agents, visit Be aware and be prepared.

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