2019 novel coronavirus family clustering in Zhejiang Province

2019 novel coronavirus family clustering in Zhejiang Province. Spencer EA, Heneghan C.


Published on July 23, 2020

Reference Sun WW, Ling F, Pan JR, et al. Epidemiological characteristics of 2019 novel coronavirus family clustering in Zhejiang Province. Zhonghua Yu Fang Yi Xue Za Zhi. 2020;54(0):E027.  2020
Study type
Country China
Setting Household
Funding Details Non reported
Transmission mode Person to person, Close contact
Exposures Family, Household

Bottom Line

Within family clusters, the number of secondary cases was two to three times higher among spouses than children, parents or other family members.

Evidence Summary

The study identified 391 cases within family clusters. These included 148 index cases, 189 secondary cases and 54 asymptomatic secondary infections. Clinical symptoms were similar for index and subsequent cases. 

Fever was the most common symptom, 114 (77%) index cases and 92 (49%) secondary cases.  

Diarrhea was unusual, experienced by seven (5%) index and five (3%) secondary cases. 

The family secondary attack rate was 32% for subsequent symptomatic cases and 43% for asymptomatic infections, and was highest among spouses of the index cases: 64%. 

Family secondary attack rate was 31% for children of the index case, 28% for parents of the index case, and 21% for other family members. 

What did they do?

Family clusters of COVID-19 in Zhejiang province, China were analyzed for epidemiological evidence. Data for family clusters occurring between 20th January and 10th February 2020 were collected. Clinical symptoms and the serial interval between index and subsequent cases were recorded. Age, sex and family relationship between index and secondary cases were investigated as risk factors, using a chi-square test.

Study reliability

Selection of the cases for study was not clear and may have introduced bias.  Conditions of quarantine among family members were not specified so the impact on secondary prevention is unclear, and it is not clear if the sample is representative outside of this setting

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

What else should I consider?

About the authors

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

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