Paediatric rotavirus gastroenteritis - regional prevalent serotypes, correlation with disease severity, nosocomial acquisition, viral co-infection and the impact of rotavirus vaccine in one region of Ireland

Abstract

Background: Rotavirus is the primary cause of gastroenteritis in children worldwide and a leading cause of gastroenteritis in children younger than three years, with a significant burden both globally and in Ireland. Rotavirus vaccine was licensed in 2006, recommended by the World Health Organisation, introduced in Ireland in October 2016. Co-infection with other viruses, in particular adenovirus, may occur in up to one third of cases, associated with severe disease. Nosocomial acquisition of rotavirus gastroenteritis results in a significant economic burden.

Objectives: 1. To determine rotavirus frequency, genotypes, disease severity, viral co infection, nosocomial acquisition, and other viral causes of gastroenteritis in our region.2. To determine the impact of rotavirus vaccine in a single district general hospital regarding admissions, duration of hospital stay, severity of disease and on seasonal characteristics of rotavirus gastroenteritis in a pre and post vaccination period.

Methods: In the post-vaccination year, from November 18th 2016 to November 18th 2017, all children up to 3 years of age who attended the Emergency Department of Mayo University Hospital or were admitted with vomiting and diarrhoea, were recruited and had their stool tested for rotavirus in addition to other enteric disease associated viruses (Adenovirus, Norovirus, Sapovirus and Astrovirus). Each week of the year was studied in relation to the total number of stool samples requested for testing of those viruses, the number of positive stool samples, their calculated median of positive stool samples in two consecutive weeks and their calculated median percentage of positive stool samples in each two consecutive week period.

Results: During the study period, gastroenteritis was the second leading cause of paediatric admissions (16%). Rotavirus gastroenteritis was a leading cause of gastroenteritis and occasionally severe; co- infection with other viruses with more severe gastroenteritis was noted. Rotavirus G1P8 including vaccine strain was the most predominant strain. RotarixTM G1P8 was only detected among previously vaccinated infants up to six months of age. Compared with the pre vaccination years (2014-2016), the median percentage of reduction of rotavirus +ve stool requests and hospital admissions were high, 48.5% and 73%, respectively. Rotavirus vaccine shortened the duration of rotavirus season in 2016/2017. Nosocomial gastroenteritis was rare.

Conclusion: Rotavirus remains the leading cause of paediatric gastroenteritis. Rotavirus strains are diverse, with the emergence of strains such as G2P4, G4P8, G12P8 and G9P8. Rotavirus co-infection, mainly with adenovirus F, is common. Nosocomial rotavirus is rare and is associated with severe disease. Compared with three pre vaccination years, rotavirus vaccine reduced the total number of gastroenteritis hospital admissions, the total number of rotavirus +ve gastroenteritis cases and shortened the duration of the rotavirus season. Rotavirus vaccine reduced severity of disease, hospital admission rate and a likely reduction in associated health care costs and utilisation.