Zostavax recipients shed varicella virus through saliva

According to a recent research study, some of the patients inoculated with Zostavax, the shingles vaccine created by Merck, shed the varicella virus through their saliva and inoculation sites for a month after immunization.

The research, conducted by Dr. Catherine DiGiorgio of the University of Texas - Houston, may have positive and negative implications on the latest recommendation by the Centers for Disease Control and Prevention that all adults over 60 receive the vaccine, according to Fierce Vaccines.

A retrospective study in January showed that Merck’s live accentuated varicella virus halved the risk of developing shingles. Dr. DiGiorgio and other researchers do not yet know if the virus shed after immunization is infectious. There may also be an upside to the research discovery.

“It could possibly have a use in clinical practice, allowing detection of shingles prior to development of the rash, enabling earlier start of antiviral therapy, and decreasing the duration of shingles and the pain of post-herpetic neuralgia,” Digiorgio said, according to Fierce Vaccines.

The prospective study found that there was virus DNA on saliva swabs of over half of the subjects 10 minutes after vaccination. Two of the patients still had varicella DNA on their saliva swabs 28 days after inoculation, Fierce Vaccines reports.

The varicella zoster virus is used in Merck’s chicken pox vaccine as well, which has been connected to documented cases of indirect infection by coming into contact with recently vaccinated individuals.