Smallpox vaccine virus transmitted by sex

NEW YORK (Reuters Health) - Researchers from the Centers for Disease Control and Prevention describe the case of a woman who developed a genital infection after having sexual contact with a military serviceman who had been recently vaccinated against smallpox.

The infection was from the vaccinia virus, the type of virus contained in the smallpox vaccine. Vaccinia is closely related but less virulent than the smallpox virus, variola, and usually results in just a localized infection.

The case, described in the CDC's Morbidity and Mortality Weekly Report, involved an otherwise healthy woman who was seen at a public health clinic in Alaska last year for painful vaginal tears that were not the result of violence or abuse. The woman reported having a new sexual partner in the days preceding the clinic visit.

A viral swab of a labial lesion was taken and sent to the Alaska State Virology Laboratory, but investigators were unable to identify the virus. The specimen was ultimately sent to the CDC where it was identified as a vaccine-strain vaccinia virus.

At a follow-up interview, the woman revealed that her new sexual partner was a male military service member stationed at a nearby base. Further investigation revealed that this individual had been vaccinated against smallpox 3 days prior to the start of his relationship with the patient.

"The most frequently reported sites of vaccinia infections caused by unintentional transfer are the face, nose, mouth, lips, genitalia, anus, and eye," according to the report. "To prevent transfers, healthcare providers should educate vaccinees regarding proper hand washing after bandage changes or other contact with the vaccination site."

Since this case surfaced, four cases of nongenital vaccinia tied to contact with recently vaccinated service members have been reported.

SOURCE: Morbidity and Mortality Weekly Report CDC Surveillance Summary, May 4, 2007.