Group A rotavirus genotypes circulating prior to implementation of a National Immunization Program in Estonia

Abstract

Group A rotaviruses (RVA) are a major cause of acute gastroenteritis in children ≤ 5 y worldwide which could be prevented with two recently introduced vaccines – monovalent Rotarix (live-attenuated G1P[8] strain) and pentavalent RotaTeq (human-bovine reassortant containing serotypes G1, G2, G3, G4 and P[8]). Prior to implementation of vaccines into national immunization program we aimed to describe RVA genotype distribution in hospitalized children aged < 5 y in Estonia during 2007–2008. A total of 671 children with confirmed RVA gastroenteritis from three major pediatric hospitals were prospectively enrolled. G- and P-genotypes were detected from 124 stool samples by semi-nested reverse transcription-PCR. Severity of disease was assessed using Clark scoring system. The majority of cases (65%) occurred in infants aged 7 to 24 mo and were of moderate severity (mean Clark score 12.1 (SD 3.2)). The prevailing strain was G2P[4] (34.7%), causing significantly more cases than G4P[8] (12.9%), G1P[8] or G9P[8] (both 4.0%), G3P[8] (1.6%). Yearly differences in genotype distribution occurred, as G2P[4] (52.8%) dominated in 2007, but G4P[8] (26.9%) in 2008. One third of strains remained non-typeable. The distribution of RVA genotypes in Estonia differs from that seen in other Central and Eastern European countries, although one should bear in mind the large proportion of P-untypeable strains and natural fluctuations of dominating RVA genotypes. Nevertheless, considering the high genotype-independent efficacy of the vaccines, introduction of national immunization should be considered.

Keywords: :

• clark score
• genotypes
• group A rotaviruses
• molecular epidemiology
• severe acute gastroenteritis

Disclosure of Potential Conflicts of Interest

The authors declare no conflict of interest related to this study.

Acknowledgments

The study was supported by the Target Financing of Estonian Ministry of Education and Research (SF0182726s06), European Union through the European Regional Development Fund and the Archimedes Foundation, an unrestricted grant from MSD, European Social Fund’s Doctoral Studies and Internationalisation Programme DoRa. We thank Doctor Tuuli Metsvaht for her critical review of the manuscript.