Prospective cohort study to investigate the burden and transmission of acute gastroenteritis in care homes: epidemiological results

Objectives To estimate the incidence of gastroenteritis in individuals in care homes. Design Prospective cohort study. Setting Five participating care homes in North West England, UK. Participants Residents and staff present at the five study care homes between 15 August 2017 and 30 May 2019 (n=268). Outcome measures We calculated incidence rates for all gastroenteritis cases per 1000 person-years at risk and per 1000 bed-days at risk. We also calculated the incidence rate of gastroenteritis outbreaks per 100 care homes per year. Results In total 45 cases were reported during the surveillance period, equating to 133.7 cases per 1000 person-years at risk. In residents the incidence rate was 0.62 cases per 1000 bed-days. We observed seven outbreaks in all care homes included in surveillance, a rate of 76.4 outbreaks per 100 care homes per year. 15 stool samples were tested; three were positive for norovirus, no other pathogens were detected. Conclusions We found that surveillance of infectious gastroenteritis disease in care homes based on outbreaks, the current general approach, detected a majority of cases of gastroenteritis. However, if policymakers are to estimate the burden of infectious gastroenteritis in this setting using only routine outbreak surveillance data and not accounting for non-outbreak cases, this study implies that the total burden will be underestimated.