Lone Simonsen, National Institute of Allergy and Infectious Diseases, NIH, 6700-B Rockledge Dr, Room 3153, Bethesda, MD, USA, Anne Elixhauser, HCUP, Agency for Healthcare Research and Quality (AHRQ), 2101 East Jefferson St., Suite 605, Rockville, MD, USA, and Meena Khare, Office of Research and Methodology, NCHS/CDC, 6525 Belcrest Road, # 915, Hyattsville, MD, USA.
KEYWORD1:
Rotavirus, Intussusception, Vaccine Adverse Events, Hospitalizations
BACKGROUND:
We have recently shown that during the 9-month Rotashield®-use period in 1998-1999, there was no increase in infant intussusception hospitalizations in 10 U.S. States. Here we extend our study to 21 States (56% of U.S. infants).
OBJECTIVE:
To compare intussusception hospitalization rates in 21 States before, during and after the Rotashield-use period. Rates in "high-user" States were compared with a group of "low-user" States (non-historic control).
METHOD:
We examined 100% electronic records of hospitalized infants (<365 days) with any mention of intussusception (ICD-9-CM 560.0) in 21 U.S. States during 1997-2000 (AHRQ/HCUP data). In these States ~321,000 infants had received >=1 doses of Rotashield (NCHS/NIS data). "High-user" States were defined as States with >=10% Rotashield coverage. Excess intussusceptions during the 9-month period of Rotashield use were estimated by comparing with intussusception rates in similar 9-month periods in surrounding years, and by comparison with "Low-user" States.
RESULT:
In the 21 States we identified 576 intussusception hospitalizations during the Rotashield-use period when 615,000 Rotashield doses were given to 321,000 infants. When comparing the Rotashield-use period to surrounding time periods, in 11 "High-user" States we found a 2.2% increase (6.5/290 intussusceptions; 230,000 vaccinees; birth cohort=1.2 million) in intussusception hospitalizations, compared to a 2.2% increase in 10 "Low-user" States.
CONCLUSION:
Despite strong evidence in other studies for a temporal association 3-14 days following a 1st Rotashield dose, the Rotashield-use period was associated with a lower total risk (nearly zero risk to 1 excess intussusception in ~34,000 vaccinees) than that extrapolated from other studies (1 excess intussusception in ~2,500-11,000 vaccinees). This paradox is best explained by Rotashield precipitating inevitable intussusception events, followed by a compensatory decrease later in infancy.
LEARNINGOBJECTIVES:
To study trends in hospital discharge data to estimate the total intussusception risk increase in the population associated with Rotashield use period.
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