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 study in the August 10 issue of JAMA, the Journal of the American Medical Association.According to background information in the article, 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.
