Hospitalizations reduced after one-dose varicella vaccine

Lopez AS. Pediatrics. 2011;doi:10.1542/peds.2010-0962.

The one-dose varicella vaccination program significantly reduced varicella-related hospitalizations and may have prevented as much as 50,000 inpatient stays during a 7-year period, according to an online report.

Adriana S. Lopez, MHS, and colleagues at the CDC examined hospital discharge data from the National Hospital Discharge Survey and Nationwide Inpatient Sample from 2000 to 2006, a period when vaccination coverage was more than 65%, but the two-dose vaccination schedule had not yet been recommended by the Advisory Committee on Immunization Practices. The immunization schedule is set for release in early February, according to the CDC.

Lopez and colleagues said rate of inpatient stays was 0.42 per 10,000 population before vaccination compared with 0.12 in the one-dose era (P<.01). Hospitalization rates decreased by more than 70% in those younger than 20 years and by 65% in those 20 years or older during the one-dose era compared with prevaccination (P<.001).

The researchers said their study adds to a growing body of evidence that shows the varicella vaccination program has significantly decreased varicella incidence and mortality in the United States.

Disclosure: The researchers reported no relevant financial disclosures.

This study reflects yet another success story of immunizations! Lopez and colleagues at the CDC have documented significant reductions in varicella-related hospitalizations among all age groups with the use of a single dose of varicella vaccine, licensed by the FDA in March, 1995. The efficacy of 1 dose of varicella vaccine ranges from 70% to 90% against infection and 95% against severe infection, the latter of which would be representative of the cases in this study. An important finding of this study was the significant decline in varicella-associated hospitalizations among the age group of patients aged 20 years and older because there was concern that routine immunization during childhood would only delay the occurrence of varicella to adulthood when the infection may be more severe. Rather, it appears that immunization of young children is resulting in some herd immunity and thus protection of susceptible older individuals. Targeting these susceptible individuals for immunization nevertheless must remain a priority. With the current recommendation since 2006 for administration of two doses of varicella vaccine to all children in the United States, the effects on hospitalization and varicella disease will be even more dramatic.

— Pablo J. Sánchez, MD

Infectious Diseases in Children Editorial Board member

Disclosure: Dr. Sánchez reports no relevant financial disclosures.

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