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Front Med (Lausanne) ; 8: 685544, 2021.
Article in English | MEDLINE | ID: covidwho-1394780


Background: While some contacts of COVID-19 cases become symptomatic and radiographically abnormal, their SARS-CoV-2 RNA tests remain negative throughout the disease course. This prospective population-based cohort study aimed to explore their characteristics and significances. Methods: From January 22, 2020, when the first COVID-19 case was identified in Hefei, China, until July 3, a total of 14,839 people in Feidong, Hefei, with a population of ~1,081,000 underwent SARS-CoV-2 RNA testing, where 36 cases (0.2%) with confirmed COVID-19 infection (Group 1) and 27 close contacts (0.2%) testing negative for SARS-CoV-2 RNA but having both positive COVID-19 exposure histories and CT findings (Group 2) from eight clusters were prospectively identified. Another 62 non-COVID-19 pneumonia cases without any exposure history (Group 3) were enrolled, and characteristics of the three groups were described and compared. We further described a cluster with an unusual transmission pattern. Results: Fever was more common in Group 2 than Groups 1 and 3. Frequency of diarrhea in Group 1 was higher than in Groups 2 and 3. Median leucocyte, neutrophil, monocyte, and eosinophil counts were all lower in Groups 1 and 2 than in Group 3. Median D-dimer level was lower in Group 1 than in Groups 2 and 3. Total protein and albumin levels were higher in Groups 1 and 2 than in Group 3. C-reactive protein level was lower and erythrocyte sedimentation rate slower in Groups 1 and 2 than in Group 3. Combination antibacterial therapy and levofloxacin were more often used in Group 3 than in Groups 1 and 2. Lopinavir/ritonavir was more often administered in Groups 1 and 2 than in Group 3. Group 1 received more often corticosteroids than Groups 2 and 3. Group 2 received less often oxygen therapy than Groups 1 and 3. Median duration from illness onset to discharge was longer in Group 1 (27 d) than Groups 2 and 3 (both 17 d). Among contacts of a confirmed COVID-19 patient, only one had a positive virus RNA test but remained asymptomatic and had negative CT findings, and three had negative virus RNA tests but had symptoms and positive CT findings, one of whom transmitted COVID-19 to another asymptomatic laboratory-confirmed patient who had no other exposures. Conclusions: Among close contacts of confirmed COVID-19 cases, some present with positive symptoms and CT findings but test negative for SARS-CoV-2 RNA using common respiratory (throat swab and sputum) specimens; they have features more similar to confirmed COVID-19 cases than non-COVID-19 pneumonia cases and might have transmitted SARS-CoV-2 to others. Such cases might add to the complexity and difficulty of COVID-19 control. Our hypothesis-generating study might suggest that SARS-CoV-2 RNA testing by rRT-PCR assays of common respiratory (throat swab and sputum) specimens alone, the widely accepted "golden standard" for diagnosing COVID-19, might be sometimes insufficient, and that further studies with some further procedures (e.g., testing via bronchoalveolar lavage or specific antibodies) would be warranted for Group 2-like patients, namely, the SARS-CoV-2 RNA-negative (tested using common respiratory specimens), radiographically positive, symptomatic contacts of COVID-19 cases, to further reveal their nature.

One Health ; 12: 100224, 2021 Jun.
Article in English | MEDLINE | ID: covidwho-1062536


BACKGROUND: Coronavirus-Disease-2019 (COVID-19) caused by Severe-Acute-Respiratory-Syndrome-Coronavirus-2 (SARS-CoV-2) is rapidly spreading worldwide causing a pandemic. To control the pandemic, the One Health approach ( is very important. We herein provide a real-world example of efficient COVID-19 control in Anhui Province, China with outbreak originating from imported cases through implementation of a series of measures as part of the One Health approach and describe the stratified cases features. METHODS: Since the identification of the first imported COVID-19 case on Jan 22, 2020, Anhui immediately initiated a sequence of systematic and forceful interventions. We detailed the control measures and analyzed the effects as demonstrated by the corresponding temporal changes of overall epidemiology data on confirmed, cured, and hospitalized cases and contacts. An accumulated number of 991 cases were confirmed, with a total number of 29,399 contacts traced. We further retrieved individual-level data of confirmed cases and compared them across stratifications by sex, age group, linkage to Wuhan, and period of diagnosis. RESULTS: With a series of interventions including active field investigation, case tracing, quarantine, centralization, education, closed management, and boundary control implemented, number of hospitalized COVID-19 cases peaked, new case disappeared, and all cases were discharged 21, 36, and 46 days after the identification of the initial case, respectively. Male patients were younger, more often had linkage to Wuhan, and received timelier care, but less often had infected cohabitants. Patients aged 25-44 years most often had linkage to Wuhan, while such frequency was lowest in those ≥65 years. Cases <25 years most often had a known contact with COVID-19 patients and any infected family member and cohabitant and were beforehand quarantined, and received fastest management. Patients with linkage to Wuhan were younger, less often had infected family member, had longer incubation period, and received earlier quarantine and timelier care. With more recent periods, the proportion of cases with linkage to Wuhan markedly decreased while the proportion of cases with known contact with COVID-19 cases dramatically increased; the proportions of patients with any infected family member or cohabitant, those beforehand quarantined, and those taking drugs before admission increased; incubation period lengthened, and patients received timelier professional care. Nonspecific systemic symptoms were most common, whose proportion decreased in more recent periods. CONCLUSIONS: Timely and powerful measures as part of the One Health approach ( effectively and efficiently controlled the COVID-19 outbreak in Anhui, which can be a good real-world example strongly demonstrating the usefulness of such measures in places with outbreaks originating from imported cases. Precise and dynamic prevention and control measures should be implemented and based on features including sex, age group, exposure history, and phase of outbreak.

J Infect ; 80(6): e1-e13, 2020 06.
Article in English | MEDLINE | ID: covidwho-47490


BACKGROUND: The outbreak of coronavirus-disease-2019 (COVID-19) has rapidly spread to many places outside Wuhan. Previous studies on COVID-19 mostly included older hospitalized-adults. Little information on infectivity among and characteristics of youngsters with COVID-19 is available. METHODS: A cluster of 22 close-contacts of a 22-year-old male (Patient-Index) including youngsters with laboratory-confirmed COVID-19 and hospitalized close-contacts testing negative for severe-acute-respiratory-syndrome-coronavirus-2 (SARS-CoV-2) in Anhui Province, China was prospectively-traced. RESULTS: Since January 23, 2020, we enrolled a cluster of eight youngsters with COVID-19 (median age [range], 22 [16-23] years; six males) originating from Patient-Index returning from Wuhan to Hefei on January 19. Patient-Index visited his 16-year-old female cousin in the evening on his return, and met 15 previous classmates in a get-together on January 21. He reported being totally asymptomatic and were described by all his contacts as healthy on January 19-21. His very first symptoms were itchy eyes and fever developed at noon and in the afternoon on January 22, respectively. Seven youngsters (his cousin and six classmates) became infected with COVID-19 after a-few-hour-contact with Patient-Index. None of the patients and contacts had visited Wuhan (except Patient-Index), or had any exposure to wet-markets, wild-animals, or medical-institutes within three months. For affected youngsters, the median incubation-period was 2 days (range, 1-4). The median serial-interval was 1 day (range, 0-4). Half or more of the eight COVID-19-infected youngsters had fever, cough, sputum production, nasal congestion, and fatigue on admission. All patients had mild conditions. Six patients developed pneumonia (all mild; one bilateral) on admission. As of February 20, four patients were discharged. CONCLUSIONS: SARS-CoV-2-infection presented strong infectivity during the incubation-period with rapid transmission in this cluster of youngsters outside Wuhan. COVID-19 developed in these youngsters had fast onset and various nonspecific atypical manifestations, and were much milder than in older patients as previously reported.

Asymptomatic Diseases/epidemiology , Contact Tracing , Coronavirus Infections/epidemiology , Coronavirus Infections/transmission , Infectious Disease Incubation Period , Pneumonia, Viral/epidemiology , Pneumonia, Viral/transmission , Adolescent , Adult , Betacoronavirus/isolation & purification , COVID-19 , China/epidemiology , Coronavirus Infections/diagnosis , Coronavirus Infections/pathology , Female , Humans , Male , Pandemics , Pneumonia, Viral/diagnosis , Pneumonia, Viral/pathology , Prospective Studies , SARS-CoV-2 , Young Adult