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. 2021 Feb 10:149:e48.
doi: 10.1017/S0950268821000327.

Epidemiologic characteristics and influencing factors of cluster infection of COVID-19 in Jiangsu Province

Jing Ai  1   2 , Naiyang Shi  2   3 , Yingying Shi  1 , Ke Xu  1 , Qigang Dai  1 , Wendong Liu  1 , Liling Chen  4 , Junjun Wang  5 , Qiang Gao  6 , Hong Ji  1 , Ying Wu  1 , Haodi Huang  1 , Ziping Zhao  7 , Hui Jin  2   3 , Changjun Bao  1   8
Affiliations

Epidemiologic characteristics and influencing factors of cluster infection of COVID-19 in Jiangsu Province

Jing Ai et al. Epidemiol Infect. .

Abstract

To understand the characteristics and influencing factors related to cluster infections in Jiangsu Province, China, we investigated case reports to explore transmission dynamics and influencing factors of scales of cluster infection. The effectiveness of interventions was assessed by changes in the time-dependent reproductive number (Rt). From 25th January to 29th February, Jiangsu Province reported a total of 134 clusters involving 617 cases. Household clusters accounted for 79.85% of the total. The time interval from onset to report of index cases was 8 days, which was longer than that of secondary cases (4 days) (χ2 = 22.763, P < 0.001) and had a relationship with the number of secondary cases (the correlation coefficient (r) = 0.193, P = 0.040). The average interval from onset to report was different between family cluster cases (4 days) and community cluster cases (7 days) (χ2 = 28.072, P < 0.001). The average time interval from onset to isolation of patients with secondary infection (5 days) was longer than that of patients without secondary infection (3 days) (F = 9.761, P = 0.002). Asymptomatic patients and non-familial clusters had impacts on the size of the clusters. The average reduction in the Rt value in family clusters (26.00%, 0.26 ± 0.22) was lower than that in other clusters (37.00%, 0.37 ± 0.26) (F = 4.400, P = 0.039). Early detection of asymptomatic patients and early reports of non-family clusters can effectively weaken cluster infections.

Keywords: COVID-19; Cluster infection; epidemiology; secondary infection.

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Conflict of interest statement

The authors declare that they have no competing interests.

Figures

Fig. 1.
Fig. 1.
Time distribution of cluster infection in Jiangsu Province.
Fig. 2.
Fig. 2.
GIS map of the city distribution of COVID-19 cluster infection in Jiangsu Province (a). The number of COVID-19 cluster infections (b). The number of COVID-19 cluster cases.
See this image and copyright information in PMC

References

    1. Drosten C et al. (2003) Identification of a novel coronavirus in patients with severe acute respiratory syndrome. New England Journal of Medicine 348, 1967–1976. - PubMed
    1. Zaki AM et al. (2012) Isolation of a novel coronavirus from a man with pneumonia in Saudi Arabia. New England Journal of Medicine 367, 1814–1820. - PubMed
    1. Wang C et al. (2020) A novel coronavirus outbreak of global health concern. Lancet 395, 470–473. - PMC - PubMed
    1. Munster VJ et al. (2020) A novel coronavirus emerging in China – key questions for impact assessment. New England Journal of Medicine 382, 692–694. - PubMed
    1. Chan JF-W et al. (2020) A familial cluster of pneumonia associated with the 2019 novel coronavirus indicating person-to-person transmission: a study of a family cluster. Lancet 395, 514–523. - PMC - PubMed

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