A report published in the Centers for Disease Control and Prevention (CDC)’s  Morbidity and Mortality Weekly Report (MMWR) indicates that between 2005–2006 and 2013–2014, the overall  incidence of varicella declined by 84.6%, with the largest declines seen in children aged 5–9 years (89.3%) and 10–14 years (84.8%).   This updated report includes data from the most recent years in the 2-dose varicella vaccination program.

Before availability of the vaccine, en estimated 4 million cases of varicella, 11,000–13,500 varicella-related hospitalizations, and 100–150 varicella-related deaths occurred annually in the United States.  Since the start of the varicella vaccination program in 1996, there has been a 97% decrease in varicella cases.   Initially,  only one dose of the vaccine was administered but continued varicella outbreaks led to the recommendation of a 2-dose schedule in 2006.

The decline in incidence has made it possible for states to implement varicella case-based surveillance and to report varicella data to CDC through the National Notifiable Diseases Surveillance System (NNDSS).  “Further reduction in the number of varicella cases will provide states with increased opportunities for enhancing varicella surveillance and improving completeness of reporting to monitor impact of the vaccination program,” the authors conclude, “These efforts will improve the accuracy of national data, provide important information for further assessment of varicella vaccination, and inform vaccination policy.”

For more information visit CDC.gov