Detection of SARS-CoV-2 RNA presence in colorectal mucus collected from patients recovering from COVID-19 for assessing the risk of exposure to the virus in medical professionals performing invasive colorectal procedures including endoscopy.

The COVID-19 pandemic not only affects millions of people, but also generates high levels of risk for medical professionals caring for their patients. It is established that the virus induces predominantly respiratory symptoms that are often culminated by the development of severe pneumonias, and COVID-19 mostly spreads through aerosol droplets generated when an infected individual coughs or sneezes. It is, however, evident that COVID-19 can also invade gastrointestinal tract, and the presence of the virus was shown in stool samples from patients not only during active disease, but also when its symptoms disappear, and the virus is no longer detectable in pharyngeal smears. The virus can also be found in the faeces of asymptomatic carriers. This means that the virus is often present in the human gut and may infect medical professionals during diagnostic or surgical procedures on gastrointestinal tract, such as commonly applied endoscopic investigations and colorectal surgery. Therefore, all these procedures apart from life-saving urgent interventions are currently suspended in the UK. Reliable tests for detecting the presence of COVID-19 in the human gut are urgently needed for protecting health of medical personnel working in gastroenterology and colorectal surgery.

Although stool testing for COVID-19 detection is possible, stool collection may be unpleasant and especially inconvenient if needed repeatedly. Moreover, the highest concentrations of the virus are expected to be present in the colorectal mucus (CM), the most informative element of the human faeces.

DiagNodus Ltd has recently developed a patient-friendly non-invasive method for CM sample collection (self-collection) that can be repeatedly applied in the same subject. Samples collected using this new method are very rich in biomarkers and suitable for detecting such major colorectal conditions as inflammatory bowel disease and colorectal cancer. Although we believe that CM samples also presents an excellent biological material for detecting infectious agents in the gut, the exploration of this direction was so far regarded only as a potential future option. The current COVID-19 pandemics has dramatically changed the situation, making it an urgent task. The main objective of the proposed pilot study, which will be undertaken by DiagNodus Ltd in collaboration with St George's Hospital and St George's University of London, is to prove the feasibility of quantitatively evaluating the presence of COVID-19 in CM during recovery after the infection, thus providing a tool for estimating the risk of exposure for medical professionals involved in gastrointestinal procedures.

Accumulation of new valuable information on the behaviour of the virus (including our early results) has led us to realising that the project will provide a range of important additional outcomes, potential exploitation of which is impossible to incorporate into the strict time frame of the originally planned project. Project extension can help exploring some of these outcomes related to both scientific and commercial aspects of the project.