COVID-19: Household transmission of SARS-CoV-2 in Wuhan.

COVID-19: Household transmission of SARS-CoV-2 in Wuhan. Spencer EA, Heneghan C.

https://www.cebm.net/study/covid-19-household-transmission-of-sars-cov-2-in-wuhan/

Published on July 8, 2020

Reference Wang Z, Ma W, Zheng X, Wu G, Zhang R. Household transmission of SARS-CoV-2. J Infect. 2020;81(1):179-182. 2020
Study type
Country China
Setting Households, Wuhan, February 2020
Funding Details This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.
Transmission mode Person to person, Close contact
Exposures Household case

Bottom Line

The observed rate of secondary transmission among household contacts of hospitalised patients with SARS-CoV-2 infection was 30%.

Evidence Summary

For the 85 study participants, there were 155 household contacts in total. 

Among 155 household contacts, 47 (30%) were diagnosed positive for SARS-CoV-2 by RT-PCR assays of throat swabs; 57 (37%) tested negative; 51 (33%) were not tested because they were asymptomatic during quarantine for at least two weeks

Of these 51 untested asymptomatic household contacts, 16 received chest computed X-ray tomography (CT) and showed no signs of viral pneumonia

The infection rate among household contacts was 38% for households containing one contact, 50% for households with two contacts, and 31% for households with three contacts.

What did they do?

On the 13th or 14th, February 2020 85 patients were admitted o Union Hospital, Wuhan with SARS-CoV-2 and their household members were recruited into an observational study. 

Cases were confirmed by real-time reverse transcription-polymerase chain reaction assays on throat swabs. Epidemiological, clinical and laboratory data of the household members were collected, and transmission rates observed.

Study reliability

This is a small study in a particular context and results need replication.  51 household contacts did not receive RT-PCR tests and some of them may have been positive (asymptomatic).  It is not clear what level of contact took place between household members and the hospitalised cases.

Clearly defined setting Demographic characteristics described Follow-up length was sufficient Transmission outcomes assessed Main biases are taken into consideration
Unclear Yes Yes Yes Unclear

What else should I consider?

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

Elizabeth Spencer

Elizabeth Spencer

Dr Elizabeth Spencer; MMedSci, PhD. Epidemiologist, Nuffield Department for Primary Care Health Sciences, University of Oxford.