Rotavirus vaccine effectiveness in preventing hospitalizations due to gastroenteritis: a descriptive epidemiological study from Germany

Abstract

Objectives: Rotavirus infections are common causes of infant hospitalization. The present study examined the effectiveness of anti-rotavirus vaccination in preventing rotavirus-related hospitalizations in Germany, following its state and nationwide introductions in 2008 and 2013, respectively.

Methods: During 15 consecutive seasons 9557 stool samples of hospitalized children of 5 years and younger with acute gastroenteritis were screened for rotavirus A. Rotavirus G and P genotypes were assessed after vaccine introduction. Vaccine effectiveness was determined by comparison of rotavirus incidence in pre-vaccine and post-vaccine cohorts. The herd effect was calculated as the difference between the observed reduction of rotavirus-related hospitalizations and the expected direct vaccine effect.

Results: The number of rotavirus-related hospitalizations declined after vaccine introduction. Approximately 26% (503/1955) of prevented cases could be attributed to the herd effect. Human rotaviruses of genotypes G3P[8], G1P[8], G9P[8], G4P[8], G2P[4] and G12P[8] were most frequent. Uncommon genotypes remained rare. The direct, indirect, total and overall vaccine effectiveness was 86% (95% confidence interval (CI) 83.2-89.1%), 48% (95% CI 42.8-52.6%), 93% (95% CI 91.3-94.3%) and 69% (95% CI 66.5-72.0%), respectively. There was no significant difference in vaccine-type or in genotype-specific vaccine effectiveness.

Conclusions: Anti-rotavirus vaccination efficiently reduced rotavirus-related hospitalizations in Germany in the past decade. The vaccines analysed in this article provide a broadly heterologous and long-lasting protection. The herd effect substantially contributed to the observed drop in the number of incidences of severe rotavirus infections. Presumably, constant high vaccine coverage will lead to a continued upward trend in the overall vaccine efficiency.

Keywords: Diversity; Epidemiology; Gastroenteritis; Genotypes; Germany; Herd protection; Immunity; Rotavirus; Vaccine introduction.