Rotavirus rates dropped in New York after vaccine introduction

New York hospitals saw a drop in the number of tests ordered for rotavirus, and reductions in hospitalizations and costs after the introduction of the rotavirus vaccine, according to a speaker at the 43^rdNational Immunization Conference, held in Dallas this week.

Hwa-Gan Chang, PhD,of the New York State Department of Health and colleague analyzed data from hospitals that averaged more than 50 diarrhea-associated admissions per year, with more than 25% of those associated with rotavirus. The researchers looked at discharge data for children aged older than 1 month but younger than 2 years between 2005 and 2008, the pre and post-vaccine eras.

Chang said the percent of rotavirus-related hospitalizations was reduced by 85% in 2008 when compared with the years 2005 and 2006 (before routine vaccine use). The researchers noted similar reductions in older age groups that do not receive the vaccine, suggesting herd immunity, she said.

Statewide, the researchers noted about $59 million average in diarrhea-associated costs for the hospitals in the first six month of 2005-2006, but that number dropped to about $50 million in 2008 for the same period.

The number of tests ordered to confirm rotavirus from four sentinel hospital associated laboratories dropped from an average of 563 in 2005-06 to 283 in 2008 for January through August, and the number of positive tests for rotavirus dropped from 225 to 21. The researchers also noted a slight delay in rotavirus onset and peak activity.

Chang noted some limitations to the study, including the fact that data for 2008 is still being compiled, and that testing practices for rotavirus varied among laboratories. – by Colleen Zacharyczuk

For more information:

Chang HG. #41. Presented at: National Immunization Conference. March 30-April 2, 2009; Dallas.

Cost-benefit analyses are always somewhat tough for me because it’s difficult to determine the cost of suffering or the value of life. When you do a big prelicensure study as was done here, with more than 70,000 children, you do it under controlled conditions and the question always remains — what will happen if you give the vaccine in the real world? What this study shows is that the rotavirus vaccine tested in prelicensure trials were shown to work in the real world. The data are very encouraging.

– Paul Offit, MD

Infectious Diseases in Children Editorial Board member