Scientific Reports (Jan 2023)

Epidemiology of GII.4 and GII.2 norovirus outbreaks in closed and semi-closed institutions in 2017 and 2018

  • Thais Cornejo-Sánchez,
  • Núria Soldevila,
  • Lorena Coronas,
  • Miquel Alsedà,
  • Pere Godoy,
  • Efrén Razquín,
  • Sara Sabaté,
  • Susana Guix,
  • Virginia Rodríguez Garrido,
  • Rosa Bartolomé,
  • Angela Domínguez,
  • the Working Group for the Study of Outbreaks of Acute Gastroenteritis in Catalonia

DOI
https://doi.org/10.1038/s41598-023-28448-9
Journal volume & issue
Vol. 13, no. 1
pp. 1 – 8

Abstract

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Abstract Norovirus infections are a leading cause of acute gastroenteritis outbreaks worldwide, with genotypes GII.2 and GII.4 being the most prevalent. The aim of this study was to compare the characteristics of GII.2 and GII.4 norovirus outbreaks reported in Catalonia in closed or semi-closed institutions in 2017 and 2018. The epidemiological and clinical characteristics of GII.2 and GII.4 outbreaks were compared using the chi-square test or Fisher's exact test for categorical variables and the Mann–Whitney U test for continuous variables. Odds ratios and their 95% confidence intervals were estimated. 61 outbreaks were reported: GII.4 was the causative agent in 12 outbreaks (30%) and GII.2 in 9 outbreaks (22.5%). GII.2 outbreaks were detected more frequently in schools or summer camps (66.7%) and GII.4 outbreaks in nursing homes (91.7%) (p = 0.01). Ninety-three people were affected in GII.2 outbreaks and 94 in GII.4 outbreaks. The median age was 15 years (range: 1–95 years) in GII.2 outbreaks and 86 years (range: 0–100 years) in GII.4 outbreaks (p < 0.001). Nausea, abdominal pain, and headache were observed more frequently in persons affected by GII.2 outbreaks (p < 0.05). Symptomatic cases presented a higher viral load suggestive of greater transmission capacity, although asymptomatic patients presented relevant loads indicative of transmission capacity.