Impact of the Maturing Varicella Vaccination Program on Varicella and Related Outcomes in the United States: 1994-2012

Background. Although the 1-dose varicella vaccination program, introduced in 1996, has led to significant declines in varicella disease, outbreaks continued to occur, which led to the adoption of a 2-dose vaccination program in 2007. We previously reported an 88% decline in varicella-related hospitalizations and a 59% decline in outpatient visits during 1994-2002. We now update data on varicella healthcare utilization with 10 years of additional data, during a period of stabilizing first-dose coverage and rapidly increasing second-dose coverage. Methods. We performed a retrospective cohort study using claims data from 1994-2012 Truven Health MarketScan databases. We examined trends in rates of varicella-related outpatient visits and hospitalizations for MarketScan enrollees aged 0-49 years, including outpatient laboratory testing, outpatient antiviral use, and pediatric strokes, with 1994-1995 as the prevaccination period and 2006-2012 as the 2-dose varicella vaccination period. Results. Varicella outpatient visits declined 84% in 2012 versus the prevaccination period, with a 60% decline during the 2-dose period. Varicella hospitalizations declined 93% in 2012 versus the prevaccination period, with a 38% decline during the 2-dose period. The proportion of those with a varicella outpatient visit having varicella laboratory testing increased from 6% in 2003 to 17% in 2012. There were 21 445 (17%) with a claim for antivirals, which was relatively stable over time. There was no reduction in pediatric strokes during 19942012. Conclusions. We document from our large study population that the varicella vaccination program has led to significant declines in outpatient visits and hospitalizations from the prevaccination period through 2012, with additional declines during the 2-dose varicella vaccination period.