Background: In 2007, based on decisions by the U.S. Advisory Committee on Immunization Practices, the CDC recommended a booster dose at 4-6 years in the varicella vaccine schedule. In 2008, a herpes zoster vaccine was recommended for use in persons age ≥60 years. The purpose of this study was to examine trends in herpes zoster hospitalization rates and assess the impact of both policy recommendations using U.S. hospital discharge data.
Methods: Nationwide Inpatient Sample discharge data from 2001 to 2015 were used to identify primary or secondary herpes zoster diagnoses. Trends in annual total and age-specific herpes zoster hospitalization rates and average length of stay were examined. Average annual rates for the pre (2001-2005) and post (2012-2015)-zoster vaccine policy eras were compared. Absolute change in herpes zoster hospitalizations were calculated.
Results: The rate difference of U.S. herpes zoster hospitalizations in the post vs. pre-zoster vaccine policy era was -1.9 per 100,000 population (6,200 fewer hospitalizations in 2015 than expected). Key age group rate differences: 0-3 years (-0.4 per 100,000; 50 fewer), 4-6 years (-0.6 per 100,000; 50 fewer), 7-14 years (-1.3 per 100,000; 400 fewer), 50-59 years (0.7 per 100,000; 300 more), 60-69 years (-2.5 per 100,000; 900 fewer), 70-79 years (-10.2 per 100,000; 2,000 fewer), 80+ years (-29.9 per 100,000; 3,600 fewer).
Conclusions: Reduction of wild-type varicella due to the 2-dose varicella vaccination recommendation may have impacted declining herpes zoster hospitalization rates among children ≤14 years. The 2008 herpes zoster vaccine may have impacted declining herpes zoster hospitalization rates for adults age ≥60 years despite vaccination coverage <31% by 2015.
Keywords: Epidemiology; Herpes zoster; Hospitalization; Nationwide inpatient sample; Policy; Trends; Varicella.
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