Sapovirus Infections in an Australian Community-Based Healthy Birth Cohort During the First 2 Years of Life

Sapoviruses cause almost 1 infection episode per child-year in Australian children aged <2 years. The incidence increased in children aged 6-23 months. About one-third of sapovirus infections were symptomatic, with vomiting the sole symptom in 52%, and 43% requiring healthcare. Background Sapovirus is an important cause of acute gastroenteritis (AGE) in young children. However, knowledge gaps remain in community settings. We investigated the epidemiology, disease characteristics, and healthcare use associated with sapovirus infections in Australian children during their first 2 years of life. Methods Children in the Brisbane-based Observational Research in Childhood Infectious Diseases birth cohort provided daily gastrointestinal symptoms (vomiting/loose stools), weekly stool swabs, and healthcare data until age 2 years. Swabs were batch-tested for sapovirus using real-time polymerase chain reaction assays. Incidence rates and estimates of associations were calculated. Results Overall, 158 children returned 11 124 swabs. There were 192 sapovirus infection episodes. The incidence rate in the first 2 years of life was 0.89 infections per child-year (95% confidence interval [CI], .76-1.05), and the symptomatic incidence rate was 0.26 episodes per child-year (95% CI, .17-.37). Age >= 6 months, the fall season, and childcare attendance increased disease incidence significantly. Fifty-four of the 180 (30%) infections with linked symptom diaries were symptomatic, with 72% recording vomiting and 48% diarrhea. Prior infection reduced risk of further infections (adjusted hazard ratio, 0.70 [95% CI, .54-.81]) in the study period. Viral loads were higher and viral shedding duration was longer in symptomatic than asymptomatic children. Twenty-three (43%) symptomatic episodes required healthcare, including 6 emergency department presentations and 2 hospitalizations. Conclusions Sapovirus infections are common in Australian children aged 6-23 months. Efforts to reduce childhood AGE after the global rollout of rotavirus vaccines should include sapovirus where estimates of its incidence in communities will be crucial.

Automated summary

Sapoviruses cause a high incidence of infection in Australian children under 2 years old, particularly in children aged 6-23 months. Around one-third of the infections are symptomatic, with vomiting being the most common symptom, and a significant proportion of these cases require healthcare.