Varicella vaccine reduces contagiousness of chickenpox.

2004 SEP 1 - (NewsRx.com & NewsRx.net) -- Children and adolescents who have received the varicella (chickenpox) vaccine and contract varicella are about half as contagious as those who have not been vaccinated, according to a new study.

Varicella is a highly infectious disease caused by the varicella zoster virus, which is spread by droplet or airborne transmission. Before the varicella vaccination program in the United States, approximately 4 million varicella cases occurred each year, resulting in 10,600 hospitalizations and 100 deaths. The majority of cases occurred in children, which reflects the highly contagious nature of the disease. Limited data are available on the contagiousness of vaccinated varicella cases.

Jane F. Seward, MPH, of the U.S. Centers for Disease Control and Prevention, Atlanta, and colleagues examined varicella transmission within households according to the varicella history and vaccination status of both the primary case and exposed household member(s) and estimated vaccine effectiveness from household secondary attack rates. Their findings were published in the August 11, 2004, issue of the Journal of the American Medical Association.

The study consisted of a population-based, active varicella surveillance project in a community of approximately 320,000 in Los Angeles County during 1997 and 2001. Varicella cases were reported by child-care centers, private and public schools, and health care clinicians and were investigated to collect demographic, ...