With the reintroduction of smallpox vaccination, detailed contemporary
descriptions of adverse reactions to the vaccine are needed to adequately
inform the public and clinicians. During a multicenter, randomized controlled
trial investigating the efficacy of various dilutions of smallpox vaccine,
we observed the appearance of a papulovesicular eruption (focal and generalized)
in study volunteers.
To characterize the papulovesicular eruptions by clinical, virologic,
and histopathological characteristics.
Design, Setting, and Participants
Prospective case series of papulovesicular eruptions following smallpox
vaccination in healthy, vaccinia-naive adult participants compared with noncases
conducted from October 2002 to March 2003. Variables potentially related to
these eruptions were collected retrospectively through chart review. Eruptions
were described based on viral culture, clinical examination, and histopathological
evaluation (1 biopsy specimen from 1 case).
Main Outcome Measure
Cases of papulovesicular eruptions following vaccination.
During the trial, of 148 volunteers (56% women; mean age 23.6 years),
4 participants (2.7%) developed generalized eruptions and 11 (7.4%) noted
focal eruptions. Viral cultures of sample lesions were negative for vaccinia.
The result of a skin biopsy sample from 1 case of generalized rash revealed
suppurative folliculitis without evidence of viral infection. All lesions
resolved without scarring. In the cohort, cases and noncases did not show
significant differences in terms of sex, in the use of nonsteroidal anti-inflammatory
drugs or oral or depo contraceptives, in medication allergies, in the incidence
of fever or lymphadenopathy after vaccination, or in the dilution of vaccine
Folliculitis is a common and benign eruption observed in vaccinia-naive
adult volunteers following smallpox vaccination. This eruption may be seen
in volunteers receiving the vaccine in the newly instituted vaccination programs
and may be met with heightened anxiety, potentially being confused with generalized
vaccinia. This description of folliculitis using clinical, virologic, and
histopathological findings should allay these concerns and provide additional
insight into this eruption.