Role of rotavirus vaccination on an emerging G8P[8] rotavirus strain causing an outbreak in central Japan

Vaccine. 2018 Jan 2;36(1):43-49. doi: 10.1016/j.vaccine.2017.11.056. Epub 2017 Nov 26.

Abstract

Background: In this study, we examined the effectiveness of RV1 and RV5 vaccines during an outbreak of G8P[8] rotavirus group A strain (G8P[8]-RVA). These vaccines were originally designed to provide protection against severe diseases caused by common circulating strains, whereas G8P[8]-RVA remains emerging strain and partially heterotypic to the vaccines. It is imperative to investigate vaccine effectiveness (VE) against G8P[8]-RVA because this strain appears to be predominant in recent years, particularly, in post-vaccine era.

Methods: RVA infection and genotypes were confirmed by polymerase chain reaction (PCR) followed by sequence-based genotyping. VE was determined during an outbreak of G8P[8]-RVA in Shizuoka Prefecture, Japan, in February-July 2017, retrospectively, by comparing vaccination status of children suffering from acute gastroenteritis (AGE) between 'PCR-positive' and 'PCR-negative' cases using conditional logistic regression adjusted for age.

Results: Among 80 AGE children, RVA was detected in 58 (73%), of which 53 (66%) was G8P[8]-RVA. The clinical characteristics of G8P[8]-RVA and other RVA strains were identically severe. Notably, the attack rates of G8P[8]-RVA in vaccinated (61.1%) and unvaccinated (65.5%) children were almost similar. Indeed, no substantial effectiveness were found against G8P[8]-RVA (VE, 14% [95% CI: -140% to 70%]) or other RVA strains (VE, 58% [95% CI: -20% to 90%]) for mild infections. However, these vaccines remained strongly effective against moderate (VE, 75% [95% CI: 1% to 40%]) and severe (VE, 92% [95% CI: 60% to 98%]) RVA infections. The disease severity including Vesikari score, duration and frequency of diarrhea, and body temperature were significantly lower in vaccinated children.

Conclusions: This study demonstrates the effectiveness of current RV vaccines against moderate and severe, but not against the mild infections during an outbreak caused by unusual G8P[8]-RVA, which was virtually not targeted in the vaccines.

Keywords: G8P[8] genotype; Outbreak; Rotavirus; Vaccine effectiveness.

MeSH terms

  • Child
  • Child, Preschool
  • Diarrhea
  • Disease Outbreaks / prevention & control
  • Disease Outbreaks / statistics & numerical data
  • Feces / virology
  • Female
  • Gastroenteritis / epidemiology
  • Gastroenteritis / prevention & control*
  • Gastroenteritis / virology
  • Genotype
  • Humans
  • Infant
  • Infant, Newborn
  • Japan / epidemiology
  • Male
  • Phylogeny
  • Polymerase Chain Reaction
  • Retrospective Studies
  • Rotavirus / genetics
  • Rotavirus / isolation & purification*
  • Rotavirus Infections / epidemiology
  • Rotavirus Infections / prevention & control*
  • Rotavirus Infections / virology
  • Rotavirus Vaccines / administration & dosage*
  • Vaccination*
  • Vaccine Potency

Substances

  • Rotavirus Vaccines