1. Home>
2. Specialties>
3. General Medicine>
4. Summary and Comment

A Look Back at the Recent Smallpox Vaccination Program

Smallpox vaccination was associated with few serious adverse events.

In late 2002, smallpox vaccination was reinstated temporarily for military personnel (590,400 doses); in early 2003, the program was expanded to include civilians at high risk (64,600 doses, mostly for health care and emergency service workers). In two studies, researchers have assessed adverse events (AEs) that were reported to the Vaccine Adverse Event Reporting System and were associated temporally with smallpox vaccination.

In the first study, 37,901 vaccinated civilians were assessed from January through October 2003. A total of 822 AEs were documented, of which 590 were reported within 14 days of vaccination and reasonably could be attributed to vaccination; 100 of these were serious: 85 resulted in hospitalization (including 21 cases of myocarditis or pericarditis), and 3 resulted in death.

In the second study, researchers focused on neurologic AEs that were reported from December 2002 through March 2004 among about 665,000 vaccinated military and civilian personnel. A total of 214 neurologic AEs were reported as being associated temporally with smallpox vaccination. Of these, 39 were considered serious, including 13 cases of meningitis, 3 cases of encephalitis or myelitis, 11 cases of Bell palsy, 9 seizure events, and 3 cases of Guillain-Barré syndrome. However, the prevalences of all serious AEs were similar to their expected prevalences in the general population.

Comment: If widespread smallpox vaccination is considered in the future, these data will be reassuring. The risk for serious AEs associated with smallpox vaccination is minimal.

— Thomas L. Schwenk, MD

Published in Journal Watch General Medicine January 10, 2006

Citation(s):

Casey CG et al. Adverse events associated with smallpox vaccination in the United States, January–October 2003. JAMA 2005 Dec 7; 294:2734-43.

• Original article (Subscription may be required)
• Medline abstract (Free)

Sejvar JJ et al. Neurologic adverse events associated with smallpox vaccination in the United States, 2002–2004. JAMA 2005 Dec 7; 294:2744-50.

• Original article (Subscription may be required)
• Medline abstract (Free)