People recently immunized against shingles may transmit herpes zoster

Last Updated: 2011-02-08 18:05:18 -0400 (Reuters Health)

By Fran Lowry

NEW ORLEANS (Reuters Health) - People who get vaccinated with the herpes zoster vaccine Zostavax to prevent shingles can shed the virus in their saliva for weeks afterward, according to research presented here at the 69th annual meeting of the American Academy of Dermatology.

Whether these people are infectious as well is not yet known, but they should probably obey the package insert that comes with the vaccine and stay away from infants, pregnant women, and immunocompromised individuals, said Dr Catherine DiGiorgio, from the Center for Clinical Studies in Houston, Texas.

"We know from previous studies that we have done in collaboration with NASA and the Johnson Space Center that astronauts shed varicella zoster virus (VZV) in their saliva when they are in space flight. We also know that shingles patients shed the virus and that the amount of pain they experience correlates with the amount of VZV they shed in saliva. Kids who are vaccinated against chicken pox also can shed the VZV virus for a while, so we wanted to see if the same was true for seniors who are being vaccinated for shingles," she told Reuters Health.

In the study, 36 healthy patients ages 60 to 90 received the Zostavax vaccine. Immediately after vaccination, the injection site was sampled for virus DNA. Saliva samples were obtained before patients were vaccinated and then on days 1 to 3, 7, 14, 21 and 28.

Fifty percent of participants had VZV DNA in skin swabs of the inoculation site obtained immediately after immunization. In addition, 58% of subjects had VZV DNA in their saliva during the first week. This percentage declined with time; the researchers found VZV DNA in saliva of 31% at 14 days, 28% at 21 days, and 6% at 28 days.

"We don't know if they are infectious," Dr. DiGiorgio said. "We just know that they are shedding, so the next study would be to find out whether or not they are actually infectious."

She added that the U.S. Food and Drug Administration has approved the vaccine against shingles for people aged 60 and older, but that younger people should consider being vaccinated as well.

"Here at the Center for Clinical Studies we see a ton of shingles patients and their average age is actually early 50s. A family history of shingles increases one's risk and we recommend that anyone with a family history get the vaccine," Dr. DiGiorgio said.

The findings from the present study suggest that people should be careful after they are vaccinated, she said. "The Zostavax package insert warns newly vaccinated individuals to stay away from newborn infants, immunosuppressed persons and pregnant women who have not had chicken pox or been vaccinated, but it doesn't say for how long and it doesn't say why they should listen."

She added, "I think it is best to be safe until we know for sure what is going on."

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