Meena Khare, Office of Research and Methodology, National Center for Health Statatistics, CDC, 6525 Belcrest Road, # 915, Hyattsville, MD, USA, Lone Simonsen, National Institute of Allergy and Infectious Diseases, NIH, 6700-B Rockledge Dr, Room 3153, Bethesda, MD, USA, and Annabella Battaglia, Abt Associates Inc, 55 Wheeler Street, Cambridge, MA, USA.
KEYWORDS:
Rotavirus, National Immunization Survey, Vaccination Coverage
BACKGROUND:
The National Immunization Survey (NIS) measures vaccination coverage for the childhood vaccines in the U.S. Rotashield, a vaccine against Rotavirus diarrhea, was used during October 1998–July 1999 and withdrawn after 9 months due to adverse events (intussusception).
OBJECTIVE:
Quantifying Rotashield coverage presents a unique challenge to NIS data interpretation because the short usage period produced a complex pattern of uptake. We addressed the effect on coverage rates of assumptions regarding population-at-risk for Rotashield immunization.
METHOD:
Using NIS interview data from January 2000-March 2002, we studied three birth cohorts with infants born during 1)March 1998-May 1999, 2)September 1998-March 1999, and 3)December 1998-April 1999. The first cohort represents all infants who were ever 1-7 months of age during the Rotashield use period and thus targeted for a 1st dose - but with very different person-time at-risk. The second and third birth cohorts are subsets focused on infants at-risk for a 1st Rotashield dose over several months. Each subset was re-weighted to represent all U.S. infants born in each age cohort.
RESULT:
We identified 27,693, 13,031, and 9,082 children with provider-reported data in three age cohorts, respectively. In the first cohort, we estimated that 1.1 million Rotashield doses were administered to 569,000 infants. The cohort-specific Rotashield coverage rates (>=1 doses) were 11.4%, 17.4% and 20.0%, respectively. We observed substantial variation in state level coverage ranging from 1%-23% in the first to 1%-32% in the second, and 1%-41% in the third cohort. Uptake of 1st Rotashield dose increased from low levels in October-November 1998, and reached stable levels by January 1999.
CONCLUSION:
Our estimate of Rotashield doses ever used agreed with Wyeth-Lederle net sales (~1.2 million doses). We demonstrated that Rotashield coverage rates varied with age cohorts and got diluted with broader age cohorts. Our findings show that a measurable effect of Rotashield use on intussusception as well as on rates of rotavirus diarrhea would be expected in high-use States.
LEARNING OBJECTIVES:
To provide data on Rotashield coverage, and to determine the robustness of such estimates in a situation where vaccine use is in flux.
See more of Poster Presentations
See more of The 37th National Immunization Conference
