SARS-CoV-2 Infection in Fecal Samples from Hong Kong
SARS-CoV-2 Infection in Fecal Samples from Hong Kong. Jefferson T, Heneghan C.
Published on July 2, 2020
Transmission Dynamics of COVID-19
||Cheung KS, Hung IFN, Chan PPY, et al. Gastrointestinal Manifestations of SARS-CoV-2 Infection and Virus Load in Fecal Samples From a Hong Kong Cohort: Systematic Review and Meta-analysis. Gastroenterology. 2020; S0016-5085(20)30448-0. 2020
Fecal discharge continues long after respiratory shedding of COVID-19 has ceased.
Honk Kong Cohort
Among the 59 patients with COVID-19 in the Hong Kong Cohort, 15 (25%) had gastrointestinal symptoms and nine (15%) had a stool that tested positive for viral RNA. Stool viral RNA was detected in 39% of those with diarrhoea and 8.7% among those without, and the median fecal viral load was higher in those with diarrhoea:
Meta-analysis of 60 studies (4243 patients)
The pooled prevalence of stool samples that were positive for virus RNA was 48% (95% CI, 38–58%): 18% had gastrointestinal symptoms.
70% of the stool samples collected after the loss of virus from respiratory specimens tested positive for the virus (95% CI, 49.6–85.1). The stool positivity rate can be up to 33 days from the onset or beyond.
What did they do?
The study first analysed data from a cohort of 59 patients with COVID-19 in Hong Kong during February 2020 and subsequently carried out a systematic review and pooling of data on the prevalence of gastrointestinal symptoms and stool excretion of viruses (from 11 studies).
The review included 53 studies on adults, 4 on pediatric patients, and 3 on pregnant women.
The authors report a timeline of the symptomatology and viral test results (respiratory and stool specimens) of 38 patients with COVID-19 which is of interest and reproduced below.
The study is a well-conducted and reported systematic review. The main problem is that the authors do not know whether the stool isolates were viable or not, i.e. whether they could transmit infection^. The Hong Kong cohort of patients was small.
|Clearly defined setting
||Demographic characteristics described
||Follow-up length was sufficient
||Transmission outcomes assessed
||Main biases are taken into consideration
What else should I consider?
The results of the review urgently need updating and the evidence base developing further
Because of the lack of systematic stool collection protocol in currently published studies, the full extent of the stool positivity rate remains to be characterized, particularly the peak timing and extent of fecal shedding. It is, however, alarming to note that 70% of patients had stool viral RNA remaining positive despite negative respiratory specimens.
About the authors
Carl is Professor of EBM & Director of CEBM at the University of Oxford. He is also a GP and tweets @carlheneghan. He has an active interest in discovering the truth behind health research findings
Tom Jefferson, epidemiologist.