Impact of rotavirus vaccine on acute gastroenteritis emergency department visits and hospitalizations in a highly-vaccinated urban cohort

Sheila M. Nolan, Priya Prasad, Alexander G. Fiks, Theoklis E. Zaoutis, Thomas R. TenHave, Susan E. Coffin

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DOI: 10.4236/ojped.2011.14012                

Abstract

Background: Rotavirus vaccines (RVV) have significantly reduced rotavirus disease in children over the past 4 years in the United States. In this study, we describe the impact of RVV in preventing acute gastroenteritis (AGE) hospital encounters in a highly-vaccinated urban pediatric network during the 2007 and 2008 rotavirus seasons. Methods: We used 5 urban practices from a practice-based network to conduct a retrospective cohort study comparing the numbers of AGE emergency department (ED) visits and hospitalizations in RVV-immunized (exposed) and non-immunized (unexposed) children during the first 2 full seasons following RVV introduction. We determined incident rate ratios (IRR), using Poisson regression, and vaccine effectiveness for each outcome. Results: The 2007 and 2008 cohorts were analyzed separately. 62% of the 2007 cohort was vaccinated and 88% of the 2008 cohort. AGE hospitalizations were significantly reduced among RVV-immunized children from the 2007 cohort in the 2008 season with vaccine effectiveness of 67%. Sub-analysis of this cohort by age revealed that RVV was most protective against hospitalizations in the youngest age group (IRR = 0.21, 95% CI (0.06, 0.82). A trend toward protection against hospitalization was detected for both cohorts in the first season following immunization that did not reach a statistically significant level. For AGE ED visits, no significant difference was seen between RVV-immunized and non-immunized children in either cohort, although there was a trend toward protection (IRR’s: 0.67 - 0.7). Conclusions: RVV was highly effective in preventing AGE hospitalizations for a subset of our cohort in 2008. Given reports of RVV effectiveness, we hypothesize that herd immunity is responsible for the inability to detect a significant difference between RVV-immunized and non-immunized children in our highly- vaccinated cohort.

Keywords

Rotavirus; Pediatrics; Acute Gastroenteritis

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	Glass, R.I., Kilgore, P.E., Holman, R.C., Jin, S., Smith, J.C., Woods, P.A., Clarke, M.J., Ho, M.S. and Gentsch, J.R. (1996) The epidemiology of rotavirus diarrhea in the United States: surveillance and estimates of disease burden. Journal of Infectious Diseases, 174, S5. doi:10.1093/infdis/174.Supplement_1.S5
[2]	Tate, J.E., Panozzo, C.A., Payne, D.C., Patel, M.M., Cortese, M.M., Fowlkes, A.L. and Parashar, U.D. (2009) Decline and change in seasonality of US rotavirus activity after the introduction of rotavirus vaccine. Pediatrics, 124, 465-471. doi:10.1542/peds.2008-3528
[3]	Cortese, M.M., Tate, J.E., Simonsen, L., Edelman, L. and Parashar UD. (2010) Reduction in gastroenteritis in United States children and correlation with early rotavirus vaccine uptake from national medical claims databases. Pediatric Infectious Disease Journal, 29, 489-494.
[4]	Coffin, S.E., Zaoutis, T.E., Wheeler Rosenquist, A.B., Heydon, K., Herrera, G., Bridges, C.B., Watson, B., Localio, R., Hodinka, R.L. and Keren, R. (2007) Incidence, complications, and risk factors for prolonged stay in children hospitalized with community-acquired influenza. Pediatrics, 119, 740-748. doi:10.1542/peds.2006-2679
[5]	Hsu, V.P., Staat, M.A., Roberts, N., Thieman, C., Bernstein, D.I., Bresee, J., Glass, R.I. and Parashar, U.D. (2005) Uses of active surveillance to validate international classification code estimates of rotavirus hospitalizations in children. Pediatrics, 115, 78-82.
[6]	Feudtner, C., Christakis, D.A. and Connell, F.A. (2000) Pediatric deaths attributable to complex chronic conditions: A population-based study of Washington state, 1980-1997. Pediatrics, 106, 205-209.
[7]	Ewell, M. (1996) Comparing methods for calculating confidence intervals for vaccine efficacy. Statistics in Medicine, 15, 2379-2392. doi:10.1002/(SICI)1097-0258(19961115)15:21<2379::AID-SIM457>3.0.CO;2-L
[8]	Wang, F.T., Mast, T.C., Glass, R.J., Loughlin, J. and Seeger, J.D. (2010) Effectiveness of the pentavalent rotavirus vaccine in preventing gastroenteritis in the United States. Pediatrics, 125, e208-e213. doi:10.1542/peds.2009-1246
[9]	Field, E.J., Vally, H., Grimwood, K. and Lambert, S.B. (2010) Pentavalent rotavirus vaccine and prevention of gastroenteritis hospitalizations in Australia. Pediatrics, 126, 506-512. doi:10.1542/peds.2010-0443
[10]	Clark, H.F., Lawley, D., Mallette, L.A., DiNubile, M.J. and Hodinka, R.L. (2009 Decline in cases of rotavirus gastroenteritis presenting to the children’s hospital of philadelphia after introduction of pentavalent rotavirus vaccine. Clinical and Vaccine Immunology, 16, 382-386. doi:10.1128/CVI.00382-08