High incidence of asymptomatic SARS-CoV-2 infection, Chongqing, China

Tao, Yang; Cheng, Panke; Wen, Chen; Wan, Peng; Chen, Yaokai; Yuan, Guodan; Chen, Junjie; Huo, Da; Guan, Ge; Sun, Dan; Tan, Ju; Yang, Guanyuan; Zeng, Wen; Zhu, Chuhong

doi:10.1101/2020.03.16.20037259

Cited by 22 publications

(22 citation statements)

References 6 publications

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“…The proportion of symptomless cases of COVID-19 has gradually increased since its rst outbreak in Wuhan, Hubei province, China [37]. One of the reasons behind this may be because of decreased toxicity of SARS-CoV-2 in the process of long chain of transmission [38].…”

Section: Discussionmentioning

confidence: 99%

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Asymptomatic people with SARS-CoV-2 as unseen carriers of COVID-19: A systematic review and meta-analysis

Syangtan

Bista

Dawadi

et al. 2020

Preprint

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Background The asymptomatic patients with SARS-CoV-2 can act as an unseen carrier for magnifying the transmission of COVID-19. Aims This study was designed to appraise the burden of asymptomatic individuals and estimate their occurrence among different age groups and gender by reviewing the existing published data on asymptomatic people with COVID-19. Methods Three electronic databases: PubMed, Embase and Web of Science (WoS) were used to search studies as per the guidelines of Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) and the search was limited to English language. The study population of this review includes asymptomatic individuals infected by COVID-19. All original articles which have reported cases of the COVID-19 patients with no symptoms until 31 April 2020 were included in the study. Random effects model was applied to analyze pooled data on the prevalence of symptomless cases among total COVID-19 infected patients and also on different age groups and gender. Results In the meta-analysis of 16 studies, comprising 2,788 COVID-19 infected patients, the pooled prevalence of asymptomatic cases was 48.2% (95% CI, 30%-67%). Among the asymptomatic patients, 55.5% (95% CI, 43.6%-66.8%) were female and 49.6% (95% CI, 20.5%-79.1%) were children. Conclusion About half of the COVID-19 infected patients were asymptomatic cases. Children and females were more apparent to be asymptomatic patient of COVID-19 and could act as unseen carrier of SARS-CoV-2. Symptom based screening only, might fail to identify all SARS-CoV-2 infections escalating the threat of global spread of SARS-CoV-2. Therefore, mass surveillance system tracking asymptomatic cases is a pressing need of public health, paying special attention to female and young children, which could aid in prevention and containment of this unprecedented pandemic.

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Section: Discussionmentioning

confidence: 99%

“…As shown in PRISMA ow diagram (Fig. 1), among them 16 articles [38,39,[52][53][54][55][56][57][58][59][60][61][62][63][64][65] were included for the quantitative meta-analysis and 99 were excluded after full text review due to the lack of information about incidence of asymptomatic COVID-19 case.…”

Section: Study Selectionmentioning

confidence: 99%

Asymptomatic people with SARS-CoV-2 as unseen carriers of COVID-19: A systematic review and meta-analysis

Syangtan

Bista

Dawadi

et al. 2020

Preprint

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“…In contrast, isolated measures like broad travel restrictions or enforced quarantine have proven less effective, as the ability to achieve "zero risk" through these measures are virtually unattainable in most contexts. Moreover, the effectiveness of these strategies are even more questionable in light of research showing asymptomatic and mildly symptomatic carriers as important vectors for community transmission of COVID-19 [7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Explaining the “Bomb-Like” Dynamics of COVID-19 with Modeling and the Implications for Policy

Lin

Bhaduri

Strauss

et al. 2020

Preprint

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Using a Bayesian approach to epidemiological compartmental modeling, we demonstrate the "bomb-like" behavior of exponential growth in COVID-19 cases can be explained by transmission of asymptomatic and mild cases that are typically unreported at the beginning of pandemic events due to lower prevalence of testing. We studied the exponential phase of the pandemic in Italy, Spain, and South Korea, and found the R0 to be 2.56 (95% CrI, 2.41-2.71), 3.23 (95% CrI, 3.06-3.4), and 2.36 (95% CrI, 2.22-2.5) if we use Bayesian priors that assume a large portion of cases are not detected. Weaker priors regarding the detection rate resulted in R0 values of 9.22 (95% CrI, 9.01-9.43), 9.14 (95% CrI, 8.99-9.29), and 8.06 (95% CrI, 7.82-8.3) and assumes nearly 90% of infected patients are identified. Given the mounting evidence that potentially large fractions of the population are asymptomatic, the weaker priors that generate the high R0 values to fit the data required assumptions about the epidemiology of COVID-19 that do not fit with the biology, particularly regarding the timeframe that people remain infectious. Our results suggest that models of transmission assuming a relatively lower R0 value that do not consider a large number of asymptomatic cases can result in misunderstanding of the underlying dynamics, leading to poor policy decisions and outcomes.

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“…In addition, negligible false-negative risk brought by PCR test were reported and the positive rates varied for different specimens in COVID-19 patients. A number of cases that were epidemiologically linked to SARS-CoV-2 exposure and with typical lung CT images still remained RNA negative in their respiratory tract specimens (10)(11)(12).…”

Section: Introductionmentioning

confidence: 99%

Evaluation of the auxiliary diagnosis value of antibodies assays for the detection of novel coronavirus (SARS-Cov-2)

Gao

Yi²,

et al. 2020

Preprint

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Background: The spread of an novel coronavirus (SARS-CoV-2, previously named 2019-nCoV) has already taken on pandemic proportions, affecting over 100 countries in a matter of weeks. Elucidating the diagnostic value of different methods, especially the auxiliary diagnosis value of antibodies assays for SARS-CoV-2 infection is helpful for improving the sensitivities of pathogenic-diagnosis, providing timely treatment, and differentiating the infected cases from the healthy, thus preventing further epidemics. Methods: Medical records from 38 patients with confirmed SARS-CoV-2 infection in the Second People's Hospital of Fuyang from January 22, 2020 to February 28, 2020 were collected and retrospectively analyzed. Specimens including throat swabs, sputum and serum were collected during the hospitalization period, viral RNAs and serum IgM-IgG antibodies to SARS-CoV-2 were measured respectively. The detectability of different methods as well as the auxiliary diagnosis value of antibodies test for SARS-CoV-2 infection were analyzed.Results: Among 38 patients, the total seropositive rate for IgM and IgG was 50.0% and 92.1%, respectively. Two patients remained seronegative throughout the course of illness. In the early phase of illness, the RNA test for sputum specimens possessed the highest detectability(92.3%), followed by the the RNA test for throat swabs (69.2%), and the antibodies assays presented lower positive rates(IgM, 23.0%, IgG, 53.8%).While, the sensitivity of antibodies assays overtook that of RNA test since day 8 after onset (IgM, 50.0%; IgG, 87.5%). Of note, the positive rate of throat swabs was only 13.0% for cases in later phase (≥15 d.a.o), and the sensitivities of IgM and IgG rose to 52.2% and 91.3%, respectively. Combined use of antibodies assay and qRT-PCR at the same time was able to improve the sensitivities of pathogenic-diagnosis, especially for the throat swabs group at the later stage of illness. Moreover, most of these cases with undetectable viral RNA in throat swabs specimens at the early stage of illness were able to be IgM/IgG seropositive after 7 days. Conclusions:The antibodies detection against SARS-CoV-2 offers vital clinical information for physicians, and could be used as an effective supplementary indicator

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High incidence of asymptomatic SARS-CoV-2 infection, Chongqing, China

Cited by 22 publications

References 6 publications

Asymptomatic people with SARS-CoV-2 as unseen carriers of COVID-19: A systematic review and meta-analysis

Asymptomatic people with SARS-CoV-2 as unseen carriers of COVID-19: A systematic review and meta-analysis

Explaining the “Bomb-Like” Dynamics of COVID-19 with Modeling and the Implications for Policy

Evaluation of the auxiliary diagnosis value of antibodies assays for the detection of novel coronavirus (SARS-Cov-2)

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