The impact of the COVID-19 pandemic on gastrointestinal infection trends in England, February – July 2020
Authors: Love Nicola K. , Elliot Alex J. , Chalmers Rachel M , Douglas Amy , Gharbia Saheer , McCormick Jacquelyn , Hughes Helen , Morbey Roger , Oliver Isabel , Vivancos Roberto , Smith Gillian 
Published: April 2021

AbstractObjectiveTo establish the impact of the first six months of the COVID-19 outbreak response of gastrointestinal (GI) infection trends in England.DesignRetrospective ecological study using routinely collected national and regional surveillance data from eight Public Health England coordinated laboratory, outbreak and syndromic surveillance systems using key dates of UK governmental policy change to assign phases for comparison between 2020 and historic data.ResultsDecreases in GI illness activity were observed across all surveillance indicators as COVID-19 cases began to peak. Compared to the 5-year average (2015-2019), during the first six months of the COVD-19 response, there was a 52% decrease in GI outbreaks reported (1,544 vs. 3,208 (95% CI: 2,938 – 3,478) and a 34% decrease in laboratory confirmed cases (27,859 vs. 42,495 (95% CI: 40,068 – 44,922). GI indicators began to rise during the first lockdown and lockdown easing, although all remained substantially lower than historic figures. Reductions in laboratory confirmed cases were observed across all age groups and both sexes, with geographical heterogeneity observed in diagnosis trends. Health seeking behaviour changed substantially, with attendances decreasing prior to lockdown across all indicators.ConclusionsThere has been a marked change in trends of GI infections in the context of the COVID-19 pandemic. The drivers of this change are likely to be multifactorial; while changes in health seeking behaviour, pressure on diagnostic services and surveillance system ascertainment have undoubtably played a role there has likely been a true decrease in the incidence for some pathogens resulting from the control measures and restrictions implemented. This suggests that if some of these changes in behaviour such as improved hand hygiene were maintained, then we could potentially see sustained reductions in the burden of GI illness.Strengths and limitations of this studyOur findings show that there has been a marked change in the burden of GI infections during the COVID-19 outbreak, and although undoubtably changes to health care and surveillance ascertainment have played a role, there does appear to be a true decrease in incidence. These findings suggest that if effective implementation of infection control measures were maintained, then we could see sustained reductions in the person to person transmission of GI illness in England.This study was strengthened by the triangulation of data from several national and regional-based surveillance systems; using this approach we could determine that the trends observed were consistent across all indicators.It has not been possible to definitively differentiate the relative contributions of the reduced ascertainment of GI infections versus a true decrease in GI disease burden in this study, which an additional focussed analysis could address.This analysis includes only the first six-months of the COVID-19 outbreak response, and further longitudinal analyses will be performed to explore this further and assess any change as we move into further phases of the pandemic