A cluster of pneumonia associated with the SARS-Cov-2 outside of Wuhan related to a house-warming banquet
Authors: Luxiang Liu, Jingjing Quan, Jiaojian Lv, Siqin Long, Wei Hu, Huang Zhuge, Zhihui Zhou, Dongdong Zhao
Journal: Journal of Infection (2020)

We read the recent published review by Han and colleagues in this journal with great interest, which described the epidemiology, clinical features and treatment of Corona Virus Disease 2019 (COVID-19) and mentioned that people who were asymptomatic or in incubation period can be the sources of infection.1Han Q. Lin Q. Jin S. You L. Coronavirus 2019-nCoV: A brief perspective from the front line.J Infect. 2020; https://doi.org/10.1016/j.jinf.2020.02.010Abstract Full Text Full Text PDF Scopus (201) Google Scholar An ongoing epidemic caused by a new coronavirus, which was formally named as SARS-Cov-2 by Coronavirus research group (CSG) of the International Committee, started in late 2019 in Wuhan, Hubei province, China and had become a worldwide public health concern.2Zhu N. Zhang D. Wang W. Li X. Yang B. Song J. et al.A Novel Coronavirus from Patients with Pneumonia in China, 2019.Engl J Med. 2020; https://doi.org/10.1056/NEJMoa2001017Crossref Scopus (18375) Google Scholar A total of 81300 cases were confirmed in China so far (March 20, 2020) and increasingly more cases were confirmed abroad, especially in Europe. On Jan 30, 2020, the WHO Emergency Committee declared the outbreak as a global health emergency. Furthermore, it still remains unclear about the origin, transmission mode and incubation period of the SARS-Cov-2. Previous research has demonstrated the person-to-person transmission of the novel Coronavirus.3Chan J.F.-W. Yuan S. Kok K.-H. To K.K.-W. Chu H. Yang J. et al.A familial cluster of pneumonia associated with the 2019 novel coronavirus indicating person-to-person transmission: a study of a family cluster.Lancet. 2020; 395: 514-523https://doi.org/10.1016/S0140-6736(20)30154-9Abstract Full Text Full Text PDF PubMed Scopus (6150) Google Scholar Here, we report the clinical features of a cluster of seven patients suffered from pneumonia associated with the SARS-Cov-2 in Lishui City of Zhejiang Province, China. Epidemiological, demographic, clinical, laboratory, radiological and treatment data were collected through detailed interviews with each patient and electronic medical records. Laboratory confirmation of the virus was performed using RT-PCR by Lishui Center for Disease Control and Prevention (CDC). Case definitions of confirmed COVID-19 are in accordance with the interim guidance from a rapid advice guideline.4Jin Y.H. Cai L. Cheng Z.S. Cheng H. Deng T. Fan Y.P. et al.A rapid advice guideline for the diagnosis and treatment of 2019 novel coronavirus (2019-nCoV) infected pneumonia (standard version).Mil Med Res. 2020; 7: 4https://doi.org/10.1186/s40779-020-0233-6Crossref PubMed Scopus (1533) Google Scholar The first enrolled patient (Patient A) returned to Lishui from Wenzhou on Jan 18, 2020 and participated a house-warming banquet. Two days later, he suffered with fever, chill, cough and generalized weakness, and was hospitalized on Jan 23, later diagnosed as COVID-19 on Jan 25. Patient B, father of patient A, presented with cough and fever on Jan 21 and was diagnosed on Jan 27. On the same day, patient C was diagnosed as COVID-19 with primary symptoms of cough and sputum. Tracking the medical history of patient C, he began to cough on Jan 16 (two days before the banquet) when he was still in Yongkang, a city adjacent to Lishui. Patient D developed a bad cough on Jan 22 and patient E presented with similar symptom on Jan 26. They were diagnosed on Feb 1 and Feb 2, respectively. Patient F was hospitalized on Jan 30 with fever, chill, cough and generalized weakness and diagnosed as COVID-19 on Feb 1. All the above six patients attended the same house-warming banquet. Oddly enough, patient G, who did not attend the same party, had fever on Feb 1 and was soon diagnosed on Feb 2. Tracing the history of epidemiology, she had dinner with patient C on Jan 24. It is worth noting that the cluster of seven patients did not go to Wuhan or Hubei province in the preceding 14 days, and they denied any exposure with wild animals, confirmed COVID-19 patients or febrile patients (Fig. 1). Two possible scenarios of transmission exist. The first and most likely scenario is that patient A acquired the infection from an asymptomatic patient in Wenzhou (a city with most cases in Zhejiang province) before Jan 18, 2020. This period overlapped with the time period during the announcement of the first case of COVID-19 in Wenzhou (symptom onset on Jan 4, diagnosed on Jan 21) according to the Zhejiang Provincial Health Committee (http://www.zjwjw.gov.cn/col/col1659205/index.html). The other five patients (B∼F) attended the same house-warming banquet and had lunch together in a crowded, noisy hotel restaurant with patient A. Even more, patient B and C had taken the same car with patient A from Lishui back to Qingyuan. As a result, all the five patients were in close contact with patient A, who most likely had been infected before. Then patient G was infected because she was exposed to patient C. The second scenario is that patient C acquired the infection in Yongkang, because he had begun coughing two days before the banquet. As described in the first scenario, other patients were all in close contact with him and got infected. Though the median incubation varies from 3∼6.4 days according to the previous studies,5Guan W.J. Ni Z.Y. Hu Y. Liang W.H. Ou C.Q. He J.X. et al.Clinical Characteristics of Coronavirus Disease 2019 in China.Engl J Med. 2020; https://doi.org/10.1056/NEJMoa2002032Crossref Scopus (20094) Google Scholar,6Xu X.W. Wu X.X. Jiang X.G. Xu K.J. Ying L.J. Ma C.L. et al.Clinical findings in a group of patients infected with the 2019 novel coronavirus (SARS-Cov-2) outside of Wuhan, China: retrospective case series.BMJ. 2020; 368: m606https://doi.org/10.1136/bmj.m606Crossref PubMed Scopus (1437) Google Scholar it is sometimes difficult to calculate the incubation period accurately such as patient A and patient C. Regardless of how the virus transmitted among the seven patients, it further indicated that the SARS-Cov-2 infection could cause clustering onset.7Chen N. Zhou M. Dong X. Qu J. Gong F. Han Y. et al.Epidemiological and clinical characteristics of 99 cases of 2019 novel coronavirus pneumonia in Wuhan, China: a descriptive study.Lancet. 2020; 395: 507-513https://doi.org/10.1016/S0140-6736(20)30211-7Abstract Full Text Full Text PDF PubMed Scopus (14212) Google Scholar Quarantine and keeping social distance paly pivotal roles in the prevention of local outbreak of COVID-19.8Wilder-Smith A. Freedman D.O. Isolation, quarantine, social distancing and community containment: pivotal role for old-style public health measures in the novel coronavirus (2019-nCoV) outbreak.J Travel Med. 2020; https://doi.org/10.1093/jtm/taaa020Crossref Scopus (1441) Google Scholar The exact transmission mode still needs to be further studied. The seven patients were aged 23–72 years old. Except patient G, the remaining 6 patients were all males. All patients had no chronic disease except patient C, who had mania years ago. On admission, cough (7/7), generalised weakness (7/7), sore throat (7/7), fever (4/7) and insomnia (4/7) were the main symptoms. The range of incubation period from exposure to symptoms was 3∼11 days (Table 1).Table 1Summary of clinical features of the cluster patients infected with SARS-Cov-2 (on admission).IndexPatient APatient BPatient CPatient DPatient EPatient FPatient GAge(Year)45725136512347SexMaleMaleMaleMaleMaleMaleFemaleOccupationBusiness manFarmerFarmerFarmerFarmerCivil servantFarmerSmokeYYNYYYNAlcohol drinking habitYYNYYYNChronic medical illnessNNManiaNNNNInterval between Admission to hospital and Symptom onset (days)34Uncertain7410.5Incubation period (days)Uncertain3Uncertain48118Presenting symptoms and signFeverYYNNNYYChillYYNNNNNCoughYYYYYYYNasal congestionYNNNYNYRhinorrhoeaYNNNYNYSneezingYNNNYNYDyspneaYNNNNNNSore throatYYYYYYYChest painNNNNNNNGeneralized weaknessYYYYYYYDiarrhoeaYNYYNNNNausea and(or) VomitingYNYNNNNHeadacheNNNNNNYInsomniaYYYNNNYBody temperature (°C)393836.336.83738.437.5Oximetry saturation (%)98959899999998N: no; Y: yes. Open table in a new tab N: no; Y: yes. Regarding the inflammatory indicators, leucocytes, neutrophils, lymphocytes and procalcitonin (PCT) of all the patients were normal and C-reactive protein (CRP) were slightly increased in three patients on admission. Liver function was mildly abnormal in one patient and no patient developed renal dysfunction. Abnormalities in chest CT images were detected among all patients, among which 5 patients showed bilateral pneumonia while only 2 patients showed unilateral pneumonia. All patients showed multiple mottling and ground­glass opacities. Compared with COVID-19 patients initially found in Wuhan, all patients in this study had mild to moderate symptoms. No complications such as acute respiratory distress syndrome, renal dysfunction, myocardial injury and secondary bacterial infection occurred. Symptoms and abnormalities in chest CT scan of all the 7 patients disappeared or significantly improved after antiviral and supportive treatments. In conclusion, this study further indicates that the SARS-Cov-2 infection can cause clustering onset, person-to-person transmission and intercity spread, and it is more likely to happen in crowded places. We urgently need to pay attention to the scale of transmission from asymptomatic or mildly symptomatic patients during the early phase of infection. The study has been approved by the research ethics committee of Lishui Peoples' Hospital (LLW-FO-403). Written informed consent has been waived in light of the urgent need to collect clinical data. None We thank the Lishui CDC for the SARS-Cov-2 nucleic acid tests. This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.