Duration of protection of pentavalent rotavirus vaccination in Nicaragua.

OBJECTIVE: To evaluate the duration of protection of pentavaent rotavirus vaccine (RV5) against rotavirus hospitalizations in Nicaragua, a developing country in Central America. METHODS: We conducted a case-control study at 4 hospitals from 2007 through 2010, including 1016 children hospitalized with laboratory-confirmed rotavirus diarrhea, 4930 controls with nonrotavirus diarrhea (ie, “test-negative”), and 5627 controls without diarrhea. All cases and controls were aged ≥6 months and born after August 2006. Outcomes included odds of antecedent vaccination between case-patients and controls, and effectiveness of vaccination (1 – adjusted odds ratio [OR] × 100). Duration of protection was assessed by comparing effectiveness among children aged <1 year compared with ≥1 year. RESULTS: Indicators of socioeconomic conditions and nonrotavirus vaccination (oral polio vaccine and diphtheria/tetanus/pertussis/hepatitis A/hepatitis B) for test-negative controls were more comparable to the rotavirus case-patients than nondiarrhea controls. RV5 vaccination was associated with a significantly lower risk of rotavirus hospitalization by using test-negative controls (OR: 0.55; 95% confidence interval [CI]: 0.41–0.74) and nondiarrhea controls (OR: 0.30; 95% CI: 0.22–0.40). Risk of rotavirus hospitalization was twofold lower among RV5 vaccinated children aged <1 year (OR: 0.36; 95% CI: 0.22–0.57) compared with RV5 vaccinated children aged ≥1 year (OR: 0.70; 95% CI: 0.47–1.05). CONCLUSIONS: RV5 provided good protection against severe rotavirus disease in Nicaragua during the first year of life, when most severe and fatal rotavirus disease in developing countries occurs. However, the decline in protection with age warrants monitoring of disease among older children and consideration of a booster dose evaluation at the end of infancy. * Abbreviations: CI — : confidence interval DTP/HiB/HepB — : diphtheria/tetanus/pertussis/ Haemophilus influenzae type b/hepatitis B ED — : emergency department EIA — : enzyme immunoassay OPV — : oral polio vaccine OR — : odds ratio RV5 — : pentavalent rotavirus vaccine VE — : vaccine effectiveness