Medical care for chickenpox down since vaccine's introduction

PHILADELPHIA – Since the varicella vaccine was introduced in the mid-1990s, the number of people receiving medical care for chickenpox in the United States has decreased sharply — particularly among children, according to a study in the March issue of The Pediatric Infectious Disease Journal.

The varicella vaccine protects against varicella zoster virus, which causes chickenpox.

"These results further emphasize the benefits of the national childhood varicella vaccination program in reducing rates of primary varicella infection," concludes the new study, led by Dr Samir S. Shah of the Children's Hospital of Philadelphia.

Shah and his colleagues used large national health care databases to compare rates of health care use for chickenpox and related problems in two periods: before (1993-95) and after (1996-2004) licensing of the chickenpox vaccine.

By 2004, the national childhood varicella vaccination rate was nearly 90 percent, according to a story posted March 15 by Newswise.

The results showed a significant two-thirds drop in the rate of visits to a physician’s office or clinic that were related to chickenpox: from 106 to 36 visits per 100,000 population. For infants and children up to age 4 years old, the rate of chickenpox-related office visits decreased by 98 percent.

The rate of hospitalizations related to chickenpox decreased by more than 50 percent: from about 31 to 15 per 100,000 population. This difference was significant in children younger than 14. The reductions in younger patients are noteworthy, because children and teens are at higher risk of rare but potentially serious complications of chickenpox.

Before and after the introduction of varicella vaccine, minority patients had higher rates of medical care for chickenpox-related problems, compared to white patients. However, the rate of chickenpox-related hospitalizations decreased for minority patients as well. The reasons for this racial difference are unclear, but could reflect differences in access to medical care, according to the study’s authors.

The Pediatric Infectious Disease Journal is the official journal of the Pediatric Infectious Diseases Society and the European Society for Paediatric Infectious Diseases.