Reduction in New York Hospitalizations for Diarrhea and Rotavirus

Background:
A new live, oral rotavirus vaccine (RotaTeq) was approved for use in the U.S. by FDA in February 2006. New York State collects information on all acute-care hospitalizations, providing a unique opportunity for monitoring the impact of new rotavirus vaccine.

Objectives:
To monitor trends in diarrhea and rotavirus-associated hospitalizations and associated costs from selected sentinel and all statewide hospitals.

Methods:
Hospitals that had averaged >50 diarrhea admissions/year with >25% of those admissions with rotavirus-coded diagnoses from 2000-2004 for children < 5 years of age were selected as sentinel hospitals. Sentinel hospital discharge data was analyzed for children 1 month-<3 years of age from 2003-2008. Similar data was analyzed for all hospitals from 2005-2008.

Results:
The percent of diarrhea hospitalizations due to rotavirus from 11 sentinel hospitals peaked in April 2008 at 28% compared with previous peaks averaging ~52% during March of 2005-2007. Diarrhea and rotavirus-associated hospitalizations were substantially lower in 2008 with an 85% reduction in the number of rotavirus-associated hospitalizations compared to 2005-2007. The percent of rotavirus-associated hospitalizations was reduced 84% for ages 12-35 months,and also 56% and 80% reductions for unimmunized children aged 36-59 months and 60 months-18 years, respectively. The hospital costs for rotavirus admissions at 11 sentinel hospitals was ~$1 million for Jan-June 2008 compared to an average of $4 million for the same period in 2005-2007. The hospital costs for all hospitals for diarrhea were reduced from over $68 million/year for 2005-2007 to $46 million for 2008 and for rotavirus from over $15 million to $3 million.

Conclusions:
In association with the recent introduction of the rotavirus vaccine, New York 2008 data showed a delay in rotavirus onset and peak activity, and significant reductions in hospitalizations and costs for diarrhea and rotavirus illness. There were also significant reductions in rotavirus hospitalizations among unimmunized older children suggesting possible herd immunity.