Cutaneous reactions associated with ACAM2000 smallpox vaccination in a deploying U.S. Army unit

Since 2003, the U.S. Army has vaccinated deploying troops for smallpox. In 2008, the U.S. military transitioned to the second-generation vaccine ACAM2000. Cutaneous adverse events associated with this vaccine are rarely characterized. We review the medical literature on cutaneous adverse events with ACAM2000 and describe four new cases that occurred in primary vaccinees at Fort Wainwright, Alaska. Four cases of disseminated papulovesicular lesions occurred out of 500 smallpox vaccinations given at Fort Wainwright, Alaska. Each case was followed by dermatology and preventive medicine. Biopsy specimens were examined at Walter Reed Army Medical Center and the U.S. Centers for Disease Control and Prevention. Three of the cases had variable clinical history of dermatitis. Case 1 experienced the most extensive lesions and case duration, and Case 4 the least. All biopsy sample results confirmed immune-mediated hypersensitivity. This study relied on self-reporting and on surveillance by unit medical staff to identify cases. Each case also received multiple other concurrent vaccinations. Further study is needed to increase our knowledge of these cutaneous reactions and demonstrate possible associated or causal factors.