Studies Show Few Side Effects from Smallpox Vaccines
Adverse events tend to be mild and occur most often in older revaccinees
TUESDAY, Dec. 6 (HealthDay News) -- Serious side effects from smallpox vaccines, including neurologic reactions, appear to be mild and limited, according to two reports in the Dec. 7 issue of the Journal of the American Medical Association.
Christine G. Casey, M.D., of the U.S. Centers for Disease Control and Prevention, and colleagues examined vaccine safety among potential first responders to a bioterrorism incident. The vaccines were administered between January and October 2003. Of the 822 reports of adverse events in the 37,901 volunteers, 72% were reported within 14 days of vaccination.
One hundred adverse events (12%) were serious, and included three deaths, as well as cases of myocarditis/pericarditis, ischemic cardiac events, vaccinia and postvaccinial encephalitis. Adverse events occurred most often in older revaccinees.
In a second study, James J. Sejvar, M.D., of the CDC, and colleagues assessed the frequency of neurologic adverse events in 665,000 people receiving smallpox vaccines from the U.S. Department of Defense and the U.S. Department of Health and Human Services between December 2002 and March 2004.
The authors found neurologic events -- including headache, non-serious limb paresthesias, pain, and dizziness or vertigo -- in 111 of the DHHS and 103 of the DoD vaccinees. Serious neurologic events included one death due to seizures, meningitis, encephalitis or myelitis, Bell palsy, seizures and Guillain-Barre syndrome.