Incidence of herpes zoster among children who received
at least one dose of varicella vaccine was lower than expected, results of a
recently published study indicated.
Researchers identified just 122 cases of herpes zoster
among 172,163 children who received the vaccine between 2002 and 2008. This is
equivalent to an estimated incidence of one case per 3,700 vaccinated children
per year.
Slightly higher, but statistically insignificant disease
rates were observed among children vaccinated after age 5 years compared with
those vaccinated between age12 and 18 months. Disease rates gradually increased
each year in the first four years after vaccination among children who were
vaccinated between age 12 and 18 months.
“The message to parents and pediatricians is that
vaccinating your child against the chicken pox is also a good way to reduce
their chances of getting herpes zoster,” Hung Fu Tseng, PhD, MPH,
study researcher and epidemiologist at the Kaiser Permanente
Department of Research and Evaluation in Pasadena, Calif., said in a
press release. “More research is needed to identify the virus strains that
cause herpes zoster.”
Delayed vaccination, severe asthma and development
disorders are other areas that should also be studied further, according to the
researchers.
Tseng HF. Pediatr Infect Dis J.
2009;28:1069-1072.
This is yet another study which demonstrates the benefit of vaccinating
against chickenpox. Not only have deaths from varicella infections declined
dramatically since introduction of the chickenpox vaccine in the 1990s, but the
longer term sequelae of chickenpox (e.g., zoster or shingles) also is
diminished. The more recent recommendations for a two-dose schedule for
varicella immunization should improve these findings even further.
– David W. Kimberlin, MD
University of Alabama at Birmingham