The Role of Orofecal Transmission

Policy recommendation

Policy should emphasise routine surveillance of food, wastewaters and effluent. The importance of strict personal hygiene measures, chlorine-based disinfection of surfaces in locations with presumed or known SARS CoV-2 activity should form part of public policy and education campaigns.

Supporting evidence

Various observational and mechanistic evidence presented throughout this evidence brief, support the hypothesis that SARS-CoV-2 can infect and be shed from the human gastrointestinal tract.

See  SARS-CoV-2 and the Role of Orofecal Transmission: Evidence Brief. Jefferson T, Spencer EA, Brassey J, Heneghan C.

Methods

We are undertaking an open evidence review investigating factors and circumstances that impact on the transmission of SARS-CoV-2, based on our published protocol. In brief, this review aims to identify and evaluate relevant articles (peer-reviewed or awaiting peer review) that examine the mode of viral transmission and ecological variables influencing the mode of transmission. Studies with modelling are only included if they report transmission outcome data, not predicted outcomes. We assess study quality based on five criteria and report important findings on an ongoing basis. When necessary we wrote to several authors of included studies for further details or clarification on the content of their articles.

Evidence update

In this first version we have summarized 36 studies examining the potential role of orofecal transmission of SARS-CoV-2 (see Table of Included Studies. COVID-19 transmission dynamics.), and included mechanistic and observational evidence from a further 22 studies (see References. Orofecal transmission potential of COVID-19). Overall the evidence is low to moderate quality (see Quality of Included Studies. COVID-19 transmission dynamics.). We provide a narrative summary of the evidence through a link at the end of each title in the left-hand column. The original paper is accessible through our summary.

Evidence summaries

TitleBottom lineTransmission modeCountry


Evidence uncertainties

Each outbreak should be investigated and a report be made publicly available rapidly. Testing of stools should be carried out in all people involved in the outbreak.

As there is coherent evidence of ingestion, penetration of enterocytes and excretion of live SARs CoV-2 in possible analogy with SARs and MERS agents we believe this working hypothesis should be tested by conducting case-control studies during the investigation of outbreaks following a set protocol.

Cases would be cases of Covid-19 (with a subset by symptom presence and severity) either fecally excreting virions or not (cases and contacts) and controls would be healthy matches.

Exposure to potentially fecally contaminated materials and protective measures taken would be elicited at interview. To minimise the play of recall and ascertainment bias, interviewers should be blind to fecal excretion status and the interview should take place as soon as possible after the event.

Viability of fecal isolates and their possible pathogenicity should be tested in outbreaks, irrespective of the presence of symptoms or nasal swab positivity.