COVID-19: Viral loads in throat and anal swabs in children infected with SARS-CoV-2

COVID-19: Viral loads in throat and anal swabs in children infected with SARS-CoV-2. Jefferson T, Heneghan C

https://www.cebm.net/study/covid-19-viral-loads-in-throat-and-anal-swabs-in-children-infected-with-sars-cov-2/

Published on June 30, 2020

Reference Yuan C, Zhu H, Yang Y, et al. Viral loads in throat and anal swabs in children infected with SARS-CoV-2. Emerg Microbes Infect. 2020;9(1):1233-1237. 2020
Study type
Country China, Wuhan
Setting Hospital records
Funding Details Top Medical Young Talents of Hubei Province.
Transmission mode Orofecal
Exposures

Bottom Line

In some children, fecal shedding may be a sign of prolonged mildly asymptomatic infection and represent the final phase of the disease.

Evidence Summary

78/212 patients were confirmed with SARS CoV-2 of which 17 had positive anal swabs, 37 had positive throat swabs, and 24 had both types of swabs positive. 

The viral loads of the 24 showed no difference even by gender and there were no significant differences in clinical features between patients with anal single positive result and throat single positive.

However, the authors report persistent anal shedding for several days after negative throat swabbing and the children with a single positive anal swab had significantly earlier onset in days (10 vs 5 days) prior to admission than those with a positive respiratory swab.

The authors speculate that anal clearance may represent the final phase of infection. 

What did they do?

The study is a retrospective case note survey of 2138 paediatric patients with suspected

SARS-CoV-2 infection in Wuhan Children’s Hospital from Jan 1st to Mar 18th, 2020. 

The aim was to evaluate the consistency of RT-PCR assay on different types of swabs in paediatric patients through the course of SARS-CoV-2 infection. RT-PCR assay on throat and anal swabs were simultaneously tested in 212/2138 paediatric patients with suspected SARS-CoV-2 infection in Wuhan Children’s Hospital.

Study reliability

The study is retrospective and no protocol is mentioned. Selection of cases (i.e. the reason for admission) is not reported, although it is reasonable to assume that symptoms or contact or both were indications for admission. The setting of provenance is not specified.

Clearly defined setting Demographic characteristics described Follow-up length was sufficient Transmission outcomes assessed Main biases are taken into consideration
Unclear Yes Yes Yes No

What else should I consider?

The results need replication. No mention of the viability of anal isolates is made.

About the authors

Carl Heneghan

Carl Heneghan

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

Tom Jefferson

Tom Jefferson is a senior associate tutor and honorary research fellow, Centre for Evidence-Based Medicine, University of Oxford.