DETECTION OF SARS-COV-2 IN THE GASTROINTESTINAL TRACT AMONG PATIENTS WITH NEGATIVE NASOPHARYNGEAL COVID-19 TESTING PRIOR TO ENDOSCOPY: A PROSPECTIVE STUDY

ABSTRACT

BACKGROUND: COVID-19 patients can have persistent viral stool positivity despite negative respiratory samples, irrespective of symptoms. These patients could potentially go undetected under the current pre-endoscopy COVID-19 testing guidance recommendations. However, the clinical significance of viral RNA in the stool remains unclear. AIMS: We aimed to prospectively determine whether SARS-CoV-2 is detected via real-time reversetranscriptase polymerase chain reaction (rRT-PCR) in the GI tract of patients scheduled for endoscopy and if the virus obtained from these clinical specimens could be isolated in culture. METHODS: All patients underwent symptom screening and had negative nasopharyngeal testing for SARS-CoV-2 within 72 hours of their scheduled procedure. Study samples were collected via repeat nasopharyngeal swab, rectal swab, and fluid from the upper GI tract and/or colon based on their endoscopic procedure(s). Samples were tested for SARSCoV-2 via rRT-PCR. Clinical specimens confirmed to be positive for SARS-CoV-2 RNA were then isolated and cultured in Vero-E6 cells. RESULTS: 243 patients (mean age 63.1 years;54.3% men) were enrolled from July 15th, 2020 to September 2nd, 2020 (Table 1). Most patients (177;72.8%) were asymptomatic, with nausea/vomiting (23;9.5%) being the most commonly reported COVID-19 related symptom. SARS-CoV-2 testing was performed from 242(99.6%) nasopharyngeal, 243(100%) rectal, 183(75.3%) upper GI tract and 73(30%) colon samples. Only 1 patient (0.4%), with a history of COVID-19 infection 45 days prior to endoscopy, tested positive for SARS-CoV-2 on all the GI clinical specimens (fluid from upper GI tract, colon, and rectal swab), despite being asymptomatic and having 3 negative nasopharyngeal swabs 40, 37 and 3 days before her procedure (Figure 1). After 14-day incubation period, there was no evidence of virus growth in cells incubated with any of these specimens. CONCLUSIONS: SARS-CoV-2 is rarely detected in the GI tract of patients with negative screening nasopharyngeal COVID-19 testing prior to endoscopy. Infectious virus was not detected by culture from any of the GI specimens positive for SARS-CoV-2 RNA by rRT-PCR. Our results further highlight that presence of viral genome on its own is not sufficient proof of infectivity. Additional studies are needed to evaluate the temporal association between COVID-19 symptom onset and potential infectivity duration in the GI tract. (Table Presented)(Figure Presented)