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Occurrence and transmission potential of asymptomatic and presymptomatic SARS-CoV-2 infections: A living systematic review and meta-analysis

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Buitrago-Garcia, Diana, Egli-Gany, Dianne, Counotte, Michel J., Hossmann, Stefanie, Imeri, Hira, Ipekci, Aziz Mert, Salanti, Georgia, Low, Nicola·2020·PLOS Medicine
DOI 10.1371/journal.pmed.1003346

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Abstract

ABSTRACT BACKGROUND There is disagreement about the level of asymptomatic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. We conducted a living systematic review and meta-analysis to address three questions: 1. amongst people who become infected with SARS-CoV-2, what proportion does not experience symptoms at all during their infection? 2. Amongst people with SARS-CoV-2 infection who are asymptomatic when diagnosed, what proportion will develop symptoms later? 3. What proportion of SARS-CoV-2 transmission is accounted for by people who are either asymptomatic throughout infection, or pre-symptomatic? METHODS AND FINDINGS We searched PubMed, Embase, bioRxiv and medRxiv using a database of SARS-CoV-2 literature that is updated daily, on 25 March 2020, 20 April 2020 and 10 June 2020. Studies of people with SARS-CoV-2 diagnosed by reverse transcriptase PCR that documented follow-up and symptom status at the beginning and end of follow-up, or modelling studies were included. One reviewer extracted data and a second verified the extraction, with disagreement resolved by discussion or a third reviewer. Risk of bias in empirical studies was assessed with an adapted checklist for case series and the relevance and credibility of modelling studies were assessed using a published checklist. We included a total of 94 studies. The overall estimate of the proportion of people who become infected with SARS-CoV-2 and remain asymptomatic throughout infection was 20% (95% CI 17-25) with a prediction interval of 3-67% in 79 studies that addressed this review question. There was some evidence that biases in the selection of participants influence the estimate. In seven studies of defined populations screened for SARS-CoV-2 and then followed, 31% (95% CI 26-37%, prediction interval 24-38%) remained asymptomatic. The proportion of people that is pre-symptomatic could not be summarised, owing to heterogeneity. The secondary attack rate was slightly lower in contacts of people with asymptomatic infection than those with symptomatic infection (relative risk 0.35, 95% CI 0.10-1.27). Modelling studies fit to data found a higher proportion of all SARS-CoV-2 infections resulting from transmission from pre-symptomatic individuals than from asymptomatic individuals. Limitations of the review include that most included studies were not designed to estimate the proportion of asymptomatic SARS-CoV-2 infections and were at risk of selection biases, we did not consider the possible impact of false negative RT-PCR results, which would underestimate the proportion of asymptomatic infections, and that the database does not include all sources. CONCLUSIONS The findings of this living systematic review of publications early in the pandemic suggest that most SARS-CoV-2 infections are not asymptomatic throughout the course of infection. The contribution of pre-symptomatic and asymptomatic infections to overall SARS-CoV-2 transmission means that combination prevention measures, with enhanced hand hygiene, masks, testing tracing and isolation strategies and social distancing, will continue to be needed. AUTHOR SUMMARY Why was this study done? ▪ The proportion of people who will remain asymptomatic throughout the course of infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the cause of coronavirus disease 2019 (covid-19), is not known. ▪ Studies that assess people at just one time point will overestimate the proportion of true asymptomatic infection because those who go on to develop covid-19 symptoms will be wrongly classified as asymptomatic, rather than pre-symptomatic. ▪ The amount, and infectiousness, of asymptomatic SARS-CoV-2 infection will determine what kind of measures will prevent transmission most effectively. What did the researchers do and find? ▪ We did a living systematic review through 10 June 2020, using automated workflows that speed up the review processes, and allow the review to be updated when relevant new evidence becomes available. ▪ Overall, in 79 studies in a range of different settings, 20% (95% confidence interval, CI 17–25%) of people with SARS-CoV-2 infection remained asymptomatic during follow-up, but biases in study designs limit the certainty of this estimate. ▪ We found some evidence that SARS-CoV-2 infection in contacts of people with asymptomatic infection is less likely than in contacts of people with symptomatic infection (relative risk 0.35, 95% CI 0.10-1.27). What do these findings mean? ▪ The findings of this living systematic review suggest that most SARS-CoV-2 infections are not asymptomatic throughout the course of infection. ▪ Future studies should be designed specifically to determine the true proportion of asymptomatic SARS-CoV-2 infections, using methods to minimise biases in the selection of study participants and ascertainment of symptom status during follow up. ▪ The contribution of pre-symptomatic and asymptomatic infections to overall SARS-CoV-2 trans

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Research works printed but not linked: 118

  1. DP Oran, 2020, Prevalence of Asymptomatic Sars-Cov-2 Infection: A Narrative Review, Ann Intern Med
  2. M Lipsitch, 2020, Defining the Epidemiology of Covid-19—Studies Needed, N Engl J Med
  3. 2017, Rapid Reviews to Strengthen Health Policy and Systems: A Practical Guide
  4. Buitrago-Garcia D, Egli-Gany D, Counotte M, Hossmann S, Imeri H, Salanti G, et al. The Role of Asymptomatic Sars-Cov-2 Infections: Rapid Living Systematic Review and Meta-Analysis. Version 1. medRxiv [Preprint]. 2020 [cited 2020 Jul 27]. Available from: https://doi.org/10.1101/2020.04.25.20079103 · DOI
  5. Buitrago-Garcia D, Egli-Gany D, Counotte M, Hossmann S, Imeri H, Salanti G, et al. The Role of Asymptomatic Sars-Cov-2 Infections: Rapid Living Systematic Review and Meta-Analysis. Version 2. medRxiv [Preprint]. 2020 [cited 2020 Jul 27]. Available from: https://doi.org/10.1101/2020.04.25.20079103 · DOI
  6. M Counotte, 2020, Covid-19 Living Evidence. Bern: Institute of Social and Preventive Medicine
  7. MH Boyle, 1998, Guidelines for Evaluating Prevalence Studies, Evid Based Ment Health, 1, 37, 10.1136/ebmh.1.2.37 · DOI · Paper page
  8. J Jaime Caro, 2014, Questionnaire to Assess Relevance and Credibility of Modeling Studies for Informing Health Care Decision Making: An Ispor-Amcp-Npc Good Practice Task Force Report., Value Health, 17, 174, 10.1016/j.jval.2014.01.003 · DOI · Paper page
  9. RG Newcombe, 1998, Two-Sided Confidence Intervals for the Single Proportion: Comparison of Seven Methods, Stat Med, 17, 857, 10.1002/(SICI)1097-0258(19980430)17:8<857::AID-SIM777>3.0.CO;2-E · DOI · Paper page
  10. Y Bai, 2020, Presumed Asymptomatic Carrier Transmission of Covid-19, JAMA, 54, E017
  11. JF Chan, 2019, Novel Coronavirus Indicating Person-to-Person Transmission: A Study of a Family Cluster, Lancet, 395, 514
  12. T Ganyani, 2020, Estimating the Generation Interval for Coronavirus Disease (Covid-19) Based on Symptom Onset Data, March 2020, Euro Surveill, 25, 10.2807/1560-7917.ES.2020.25.17.2000257 · DOI · Paper page
  13. Z Hu, 2020, Clinical Characteristics of 24 Asymptomatic Infections with Covid-19 Screened among Close Contacts in Nanjing, China. Sci China Life Sci, 63, 706, 10.1007/s11427-020-1661-4 · DOI · Paper page
  14. Liao J, Fan S, Chen J, Wu J, Xu S, Guo Y, et al. Epidemiological and Clinical Characteristics of Covid-19 in Adolescents and Young Adults. medRxiv [Preprint]. 2020. Available from: https://www.medrxiv.org/content/10.1101/2020.03.10.20032136v1 · DOI
  15. SH Luo, 2020, A Confirmed Asymptomatic Carrier of 2019 Novel Coronavirus, Chin Med J (Engl), 133, 1123, 10.1097/CM9.0000000000000798 · doi:10.1097/cm9.0000000000000798
  16. K Mizumoto, 2020, Estimating the Asymptomatic Proportion of Coronavirus Disease 2019 (Covid-19) Cases on Board the Diamond Princess Cruise Ship, Yokohama, Japan, 2020, Euro Surveill, 25, 10.2807/1560-7917.ES.2020.25.10.2000180 · DOI · Paper page
  17. H Nishiura, 2020, Estimation of the Asymptomatic Ratio of Novel Coronavirus Infections (Covid-19), Int J Infect Dis
  18. G Qian, 2020, A Covid-19 Transmission within a Family Cluster by Presymptomatic Infectors in China, Clin Infect Dis, 71, 861, 10.1093/cid/ciaa316 · DOI · Paper page
  19. Tabata S, Imai K, Kawano S, Ikeda M, Kodama T, Miyoshi K, et al. Non-Severe Vs Severe Symptomatic Covid-19: 104 Cases from the Outbreak on the Cruise Ship 'Diamond Princess' in Japan. medRxiv [Preprint]. 2020 [cited 2020 Jul 27]. doi: 10.1101/2020.03.18.20038125 · DOI
  20. Y Arima, 2020, Severe Acute Respiratory Syndrome Coronavirus 2 Infection among Returnees to Japan from Wuhan, China, 2020, Emerg Infect Dis, 26, 10.3201/eid2607.200994 · DOI
  21. N Breslin, 2020, Covid-19 Infection among Asymptomatic and Symptomatic Pregnant Women: Two Weeks of Confirmed Presentations to an Affiliated Pair of New York City Hospitals, Am J Obstet Gynecol MFM, 100118, 10.1016/j.ajogmf.2020.100118 · DOI · Paper page
  22. TQM Le, 2020, Severe Acute Respiratory Syndrome Coronavirus 2 Shedding by Travelers, Vietnam, 2020, Emerg Infect Dis
  23. L Chang, 2020, Severe Acute Respiratory Syndrome Coronavirus 2 Rna Detected in Blood Donations, Emerg Infect Dis, 26, 10.3201/eid2607.200839 · DOI · Paper page
  24. K Danis, 2020, Cluster of Coronavirus Disease 2019 (Covid-19) in the French Alps, 2020, Clin Infect Dis
  25. X He, 2020, Temporal Dynamics in Viral Shedding and Transmissibility of Covid-19, Nat Med
  26. S Hoehl, 2020, Evidence of Sars-Cov-2 Infection in Returning Travelers from Wuhan, China, N Engl J Med, 382, 1278, 10.1056/NEJMc2001899 · DOI · Paper page
  27. A Kimball, 2020, Asymptomatic and Presymptomatic Sars-Cov-2 Infections in Residents of a Long-Term Care Skilled Nursing Facility—King County, Washington, March 2020, MMWR Morb Mortal Wkly Rep, 69, 377, 10.15585/mmwr.mm6913e1 · DOI · Paper page
  28. Luo L, Liu D, Liao X-l, Wu X-b, Jing Q-l, Zheng J-z, et al. Modes of Contact and Risk of Transmission in Covid-19 among Close Contacts. bioRxiv [Preprint]. 2020 [cited 2020 Jul 27]. Available from: https://www.medrxiv.org/content/10.1101/2020.03.24.20042606v1 · DOI
  29. T Lytras, 2020, High Prevalence of Sars-Cov-2 Infection in Repatriation Flights to Greece from Three European Countries, J Travel Med
  30. H Meng, 2020, Imaging and Clinical Course of Asymptomatic Cases with Covid-19 Pneumonia at Admission in Wuhan, China, CtJ Infect
  31. WA Pongpirul, 2020, Clinical Characteristics of Patients Hospitalized with Coronavirus Disease, Thailand, Emerg Infect Dis, 26, 10.3201/eid2607.200598 · DOI
  32. H Qiu, 2020, Clinical and Epidemiological Features of 36 Children with Coronavirus Disease 2019 (Covid-19) in Zhejiang, China: An Observational Cohort Study, Lancet Infect Dis
  33. KC See, 2020, Covid-19: Four Paediatric Cases in Malaysia, Int J Infect Dis, 94, 125, 10.1016/j.ijid.2020.03.049 · doi:10.1016/j.ijid.2020.03.049
  34. YP Tan, 2020, Epidemiologic and Clinical Characteristics of 10 Children with Coronavirus Disease 2019 in Changsha, China, J Clin Virol., 127, 104353, 10.1016/j.jcv.2020.104353 · DOI
  35. Tian S, Wu M, Chang Z, Wang Y, Zhou G, Zhang W, et al. Epidemiological Investigation and Intergenerational Clinical Characteristics of 24 Covid-19 Patients Associated with Supermarket Cluster. bioRxiv [Preprint]. 2020 [cited 2020 Jul 27]. doi: 10.1101/2020.04.11.20058891 · doi:10.1101/2020.04.11.20058891
  36. ZD Tong, 2020, Potential Presymptomatic Transmission of Sars-Cov-2, Zhejiang Province, China, 2020, Emerg Infect Dis, 26, 1052, 10.3201/eid2605.200198 · DOI · Paper page
  37. X Wang, 2020, Characteristics of Non-Critically Ill Patients with Novel Coronavirus Infection (Covid-19) in a Fangcang Hospital, Clin Microbiol Infect
  38. Y Wang, 2020, Clinical Outcome of 55 Asymptomatic Cases at the Time of Hospital Admission Infected with Sars-Coronavirus-2 in Shenzhen, China, J Infect Dis
  39. Z Wang, 2020, Household Transmission of Sars-Cov-2, J Infect
  40. Yang N, Shen Y, Shi C, Ma AHY, Zhang X, Jian X, et al. In-Flight Transmission Cluster of Covid-19: A Retrospective Case Series. bioRxiv [Preprint]. 2020 [cited 2020 Jul 27]. doi: 10.1101/2020.03.28.20040097 · doi:10.1101/2020.03.28.20040097
  41. F Ye, 2020, Delivery of Infection from Asymptomatic Carriers of Covid-19 in a Familial Cluster, Int J Infect Dis, 94, 133, 10.1016/j.ijid.2020.03.042 · DOI · Paper page
  42. J Zhang, 2020, Familial Cluster of Covid-19 Infection from an Asymptomatic, Crit Care
  43. Zhang W. Estimating the Presymptomatic Transmission of Covid19 Using Incubation Period and Serial Interval Data. bioRxiv [Preprint]. 2020 [cited 2020 Jul 27]. doi: 10.1101/2020.04.02.20051318 · DOI
  44. X Zhou, 2020, Follow-up of Asymptomatic Patients with Sars-Cov-2 Infection, Clin Microbiol Infect
  45. L Zou, 2020, Sars-Cov-2 Viral Load in Upper Respiratory Specimens of Infected Patients, N Engl J Med, 382, 1177, 10.1056/NEJMc2001737 · DOI · Paper page
  46. Alshami AA, Alattas RA, Anan HF, Al Qahtani HS, Al Mulhim MA, Alahilmi AA, et al. Silent Disease and Loss of Taste and Smell Are Common Manifestations of Sars-Cov-2 Infection in a Quarantine Facility: First Report from Saudi Arabia. medRxiv [Preprint]. 2020 [cited 2020 Jul 27]. doi: 10.1101/2020.05.13.20100222 · doi:10.1101/2020.05.13.20100222
  47. HO Al-Shamsi, 2020, Screening for Covid-19 in Asymptomatic Patients with Cancer in a Hospital in the United Arab Emirates, JAMA Oncol
  48. M Andrikopoulou, 2020, Symptoms and Critical Illness among Obstetric Patients with Coronavirus Disease 2019 (Covid-19) Infection, Obstet Gynecol
  49. L Angelo Vaira, 2020, Olfactory and Gustatory Function Impairment in Covid-19 Patients: Italian Objective Multicenter-Study, Head Neck
  50. MM Arons, 2020, Presymptomatic Sars-Cov-2 Infections and Transmission in a Skilled Nursing Facility, N Engl J Med
  51. K Bai, 2020, Clinical Analysis of 25 Novel Coronavirus Infections in Children, Pediatr Infect Dis J
  52. Q Bi, 2020, Epidemiology and Transmission of Covid-19 in 391 Cases and 1286 of Their Close Contacts in Shenzhen, China: A Retrospective Cohort Study, Lancet Infect Dis
  53. MM Bohmer, 2020, Investigation of a Covid-19 Outbreak in Germany Resulting from a Single Travel-Associated Primary Case: A Case Series, Lancet Infect Dis
  54. S Brandstetter, 2020, Symptoms and Immunoglobulin Development in Hospital Staff Exposed to a Sars-Cov-2 Outbreak., Pediatr Allergy Immunol
  55. Casey M, Griffin J, McAloon CG, Byrne AW, Madden JM, McEvoy D, et al. Estimating Pre-Symptomatic Transmission of Covid-19: A Secondary Analysis Using Published Data. medRxiv [Preprint]. 2020 [cited 2020 Jul 27]. doi: 10.1101/2020.05.08.20094870 · DOI
  56. Chang MC, Hur J, Park D. Chest Computed Tomography Findings in Asymptomatic Patients with Covid-19. medRxiv [Preprint]. 2020 [cited 2020 Jul 27]. doi: 10.1101/2020.05.09.20096370 · doi:10.1101/2020.05.09.20096370
  57. Chaw L, Koh WC, Jamaludin SA, Naing L, Alikhan MF, Wong J. Sars-Cov-2 Transmission in Different Settings: Analysis of Cases and Close Contacts from the Tablighi Cluster in Brunei Darussalam. medRxiv [Preprint]. 2020 [cited 2020 Jul 27]. doi: 10.1101/2020.05.04.20090043 · doi:10.1101/2020.05.04.20090043
  58. HY Cheng, 2020, Contact Tracing Assessment of Covid-19 Transmission Dynamics in Taiwan and Risk at Different Exposure Periods before and after Symptom Onset, JAMA Intern Med
  59. PG Choe, 2020, Selecting Coronavirus Disease 2019 Patients with Negligible Risk of Progression: Early Experience from Non-Hospital Isolation Facility in Korea, Korean J Intern Med
  60. AV Dora, 2020, Universal and Serial Laboratory Testing for Sars-Cov-2 at a Long-Term Care Skilled Nursing Facility for Veterans—Los Angeles, California, 2020, MMWR Morb Mortal Wkly Rep
  61. Emery JC, Russel TW, Liu Y, Hellewell J, Pearson CA, group Cnw, et al. The Contribution of Asymptomatic Sars-Cov-2 Infections to Transmission—a Model-Based Analysis of the Diamond Princess Outbreak. medRxiv [Preprint]. 2020 [cited 2020 Jul 27]. doi: 10.1101/2020.05.07.20093849 · doi:10.1101/2020.05.07.20093849
  62. Y Gao, 2020, A Cluster of the Corona Virus Disease 2019 Caused by Incubation Period Transmission in Wuxi, China, J Infect
  63. N Graham, 2020, Sars-Cov-2 Infection, Clinical Features and Outcome of Covid-19 in United Kingdom Nursing Homes, J Infect
  64. D Hijnen, 2020, Sars-Cov-2 Transmission from Presymptomatic Meeting Attendee, Germany, Emerg Infect Dis
  65. L Huang, 2020, Initial Ct Imaging Characters of an Imported Family Cluster of Covid-19, Clin Imaging
  66. R Huang, 2020, A Family Cluster of Covid-19 Involving an Asymptomatic Case with Persistently Positive Sars-Cov-2 in Anal Swabs, Travel Med Infect Dis
  67. X Jiang, 2020, Asymptomatic Sars-Cov-2 Infected Case with Viral Detection Positive in Stool but Negative in Nasopharyngeal Samples Lasts for 42 Days, J Med Virol
  68. XL Jiang, 2020, Transmission Potential of Asymptomatic and Paucisymptomatic Sars-Cov-2 Infections: A Three-Family Cluster Study in China, J Infect Dis
  69. SE Kim, 2020, Viral Kinetics of Sars-Cov-2 in Asymptomatic Carriers and Presymptomatic Patients, Int J Infect Dis
  70. Kim Y, Chun JY, Baek G. Transmission Onset Distribution of Covid-19 in South Korea. medRxiv [Preprint]. 2020 [cited 2020 Jul 27]. doi: 10.1101/2020.05.13.20101246 · doi:10.1101/2020.05.13.20101246
  71. W Kong, 2020, Comparison of Clinical and Epidemiological Characteristics of Asymptomatic and Symptomatic Sars-Cov-2 Infection: A Multi-Center Study in Sichuan Province, China, Travel Med Infect Dis
  72. Kumar R, Bhattacharya B, Meena VP, Aggarwal A, Tripathi M, Soneja M, et al. Management of Mild Covid-19: Policy Implications of Initial Experience in India. medRxiv [Preprint]. 2020 [cited 2020 Jul 27]. doi: 10.1101/2020.05.20.20107664 · doi:10.1101/2020.05.20.20107664
  73. E Lavezzo, 2020, Suppression of a Sars-Cov-2 Outbreak in the Italian Municipality of Vo', Nature
  74. Lombardi A, Consonni D, Carugno M, Bozzi G, Mangioni D, Muscatello A, et al. Characteristics of 1,573 Healthcare Workers Who Underwent Nasopharyngeal Swab for Sars-Cov-2 in Milano, Lombardy, Italy. medRxiv [Preprint]. 2020 [cited 2020 Jul 27]. doi: 10.1101/2020.05.07.20094276 · doi:10.1101/2020.05.07.20094276
  75. V London, 2020, The Relationship between Status at Presentation and Outcomes among Pregnant Women with Covid-19, Am J Perinatol
  76. Y Lu, 2020, Infection Is Associated with Prolonged Duration of Viral Shedding in Mild Coronavirus Disease 2019: A Retrospective Study of 110 Children in Wuhan, SymptomaticPediatr Infect Dis J
  77. Y Luo, 2020, Asymptomatic Sars-Cov-2 Infection in Household Contacts of a Healthcare Provider, Wuhan, China, Emerg Infect Dis
  78. Y Ma, 2020, Characteristics of Asymptomatic Patients with Sars-Cov-2 Infection in Jinan, China. Microbes Infect
  79. M Melgosa, 2020, Sars-Cov-2 Infection in Spanish Children with Chronic Kidney Pathologies, Pediatr Nephrol
  80. MA Merza, 2020, Covid-19 Outbreak in Iraqi Kurdistan: The First Report Characterizing Epidemiological, Clinical, Laboratory, and Radiological Findings of the Disease, Diabetes Metab Syndr Clin Res Rev
  81. JY Noh, 2020, Asymptomatic Infection and Atypical Manifestations of Covid-19: Comparison of Viral Shedding Duration, J Infect
  82. SY Park, 2020, Coronavirus Disease Outbreak in Call Center, South Korea, Emerg Infect Dis
  83. CM Peak, 2020, Individual Quarantine Versus Active Monitoring of Contacts for the Mitigation of Covid-19: A Modelling Study, Lancet Infect Dis
  84. C Qiu, 2020, Transmission and Clinical Characteristics of Coronavirus Disease 2019 in 104 Outside-Wuhan Patients, China, J Med Virol
  85. L Rivett, 2020, Screening of Healthcare Workers for Sars-Cov-2 Highlights the Role of Asymptomatic Carriage in Covid-19 Transmission, Elife, 9, 10.7554/eLife.58728 · DOI · Paper page
  86. AC Roxby, 2020, Outbreak Investigation of Covid-19 among Residents and Staff of an Independent and Assisted Living Community for Older Adults in Seattle, Washington, JAMA Intern Med
  87. V Schwierzeck, 2020, First Reported Nosocomial Outbreak of Severe Acute Respiratory Syndrome Coronavirus 2 (Sars-Cov-2) in a Pediatric Dialysis Unit, Clin Infect Dis
  88. Sharma AK, Ahmed A, Baig VN, Dhakad P, Dalela G, Kacker S, et al. Characteristics and Outcomes of Hospitalized Young Adults with Mild to Moderate Covid-19 at a University Hospital in India. medRxiv [Preprint]. 2020 [cited 2020 Jul 27]. doi: 10.1101/2020.06.02.20106310 · DOI
  89. Solbach W, Schiffner J, Backhaus I, Burger D, Staiger R, Tiemer B, et al. Antibody Profiling of Covid-19 Patients in an Urban Low-Incidence Region in Northern Germany. medRxiv [Preprint]. 2020 [cited 2020 Jul 27]. doi: 10.1101/2020.05.30.20111393 · DOI
  90. W Song, 2020, Clinical Features of Pediatric Patients with Coronavirus Disease (Covid-19), J Clin Virol
  91. X Tan, 2020, Clinical Features of Children with Sars-Cov-2 Infection: An Analysis of 13 Cases from Changsha, China, Zhongguo Dang Dai Er Ke Za Zhi
  92. Pham TQ, Rabaa MA, Duong LH, Dang TQ, Tran QD, Quach HL, et al. The First 100 Days of Sars-Cov-2 Control in Vietnam. medRxiv [Preprint]. 2020 [cited 2020 Jul 27]. doi: 10.1101/2020.05.12.20099242 · doi:10.1101/2020.05.12.20099242
  93. TA Treibel, 2020, Covid-19: Pcr Screening of Asymptomatic Health-Care Workers at London Hospital, Lancet
  94. Y Wang, 2020, Characterization of an Asymptomatic Cohort of Sars-Cov-2 Infected Individuals Outside of Wuhan, China, Clin Infect Dis
  95. J Wong, 2020, High Proportion of Asymptomatic and Presymptomatic Covid-19 Infections in Travelers and Returning Residents to Brunei, J Travel Med
  96. HP Wu, 2020, Clinical Features of Coronavirus Disease 2019 in Children Aged <18 Years in Jiangxi, China: An Analysis of 23 Cases, Zhongguo Dang Dai Er Ke Za Zhi, 22, 419
  97. J Wu, 2020, Household Transmission of Sars-Cov-2, Zhuhai, China, 2020, Clin Infect Dis
  98. Xu H, Liu E, Xie J, Smyth R, Zhou Q, Zhao R, et al. A Follow-up Study of Children Infected with Sars-Cov-2 from Western China. medRxiv [Preprint]. 2020 [cited 2020 Jul 27]. doi: 10.1101/2020.04.20.20073288 · doi:10.1101/2020.04.20.20073288
  99. T Xu, 2020, Epidemiological and Clinical Features of Asymptomatic Patients with Sars-Cov-2 Infection, J Med Virol
  100. R Yang, 2020, Comparison of Clinical Characteristics of Patients with Asymptomatic Vs Symptomatic Coronavirus Disease 2019 in Wuhan, China, JAMA Netw Open
  101. Z Yongchen, 2020, Different Longitudinal Patterns of Nucleic Acid and Serology Testing Results Based on Disease Severity of Covid-19 Patients, Emerg Microbes Infect
  102. B Zhang, 2020, Positive Rectal Swabs in Young Patients Recovered from Coronavirus Disease 2019 (Covid-19), J Infect
  103. W Zhang, 2020, Secondary Transmission of Coronavirus Disease from Presymptomatic Persons, China, Emerg Infect Dis
  104. Zhang W, Long Q, Huang Y, Chen C, Wu J, Hong Y, et al. Asymptomatic Covid-19 Have Longer Treatment Cycle Than Moderate Type of Confirmed Patients. medRxiv [Preprint]. 2020 [cited 2020 Jul 27]. doi: 10.1101/2020.05.16.20103796 · doi:10.1101/2020.05.16.20103796
  105. Zhang Z, Xiao T, Wang Y, Yuan J, Ye H, Wei L, et al. Early Viral Clearance and Antibody Kinetics of Covid-19 among Asymptomatic Carriers. medRxiv [Preprint]. 2020 [cited 2020 Jul 27]. doi: 10.1101/2020.04.28.20083139 · DOI
  106. R Zhou, 2020, Viral Dynamics in Asymptomatic Patients with Covid-19, Int J Infect Dis
  107. Savvides C, Siegel R. Asymptomatic and Presymptomatic Transmission of Sars-Cov-2: A Systematic Review. medRxiv [Preprint]. 2020 [cited 2020 Jul 27]. doi: 10.1101/2020.06.11.20129072 32587980. · DOI
  108. NVV Chau, 2020, The Natural History and Transmission Potential of Asymptomatic Sars-Cov-2 Infection, Clin Infect Dis
  109. LM Kucirka, 2020, Variation in False-Negative Rate of Reverse Transcriptase Polymerase Chain Reaction-Based Sars-Cov-2 Tests by Time since Exposure, Ann Intern Med
  110. C Heneghan, 2020, Covid-19: What Proportion Are Asymptomatic?
  111. J He, 2020, Proportion of Asymptomatic Coronavirus Disease 2019 (Covid-19): A Systematic Review and Meta-Analysis, J Med Virol
  112. Beale S, Hayward A, Shallcross L, Aldridge RW, Fragaszy E. A Rapid Review of the Asymptomatic Proportion of Pcr-Confirmed Sars-Cov-2 Infections in Community Settings. medRxiv [Preprint]. 2020 [cited 2020 Jul 27]. doi: 10.1101/2020.05.20.20108183 · doi:10.1101/2020.05.20.20108183
  113. Byambasuren O, Cardona M, Bell K, Clark J, McLaws ML, Glasziou P. Estimating the Extent of True Asymptomatic Covid-19 and Its Potential for Community Transmission: Systematic Review and Meta-Analysis. medRxiv [Preprint]. 2020 [cited 2020 Jul 27]. doi: 10.1101/2020.05.10.20097543 · doi:10.1101/2020.05.10.20097543
  114. M. Day, 2020, Covid-19: Four Fifths of Cases Are Asymptomatic, China Figures Indicate, BMJ, 369, m1375, 10.1136/bmj.m1375 · DOI · Paper page
  115. JJ Deeks, 2020, Antibody Tests for Identification of Current and Past Infection with Sars-Cov-2., Cochrane Database Syst Rev, 6, CD013652
  116. WE Wei, 2020, Presymptomatic Transmission of Sars-Cov-2—Singapore, January 23-March 16, 2020, MMWR Morb Mortal Wkly Rep, 69, 411, 10.15585/mmwr.mm6914e1 · DOI · Paper page
  117. JF Ludvigsson, 2020, Systematic Review of Covid-19 in Children Shows Milder Cases and a Better Prognosis Than Adults, Acta Paediatr, 109, 1088, 10.1111/apa.15270 · DOI · Paper page
  118. V von Wyl, 2020, A Research Agenda for Digital Proximity Tracing Apps, Swiss Med Wkly, 150, w20324, 10.4414/smw.2020.20324 · DOI

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Metadata

Authors
Buitrago-Garcia, D., Egli-Gany, D., Counotte, M. J., Hossmann, S., Imeri, H., Ipekci, A. M., Salanti, G., & Low, N.
Venue
PLOS Medicine
Publisher
Public Library of Science (PLoS)
Published
2020-09-22
Volume
17
Issue
9
Pages
e1003346
ISSN
  • 1549-1277 (ISSN-L)
  • 1549-1676
DOI
10.1371/journal.pmed.1003346
OpenAlex
W3087248341
Cited by
1,000
References
8
FWCI
8.52
Type
journal article
Language
en
Open access
gold
Licence
creativecommons.org/licenses/by/4.0/ (vor)
Funders
  • Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung (320030_176233)
  • European Union Horizon 2020 research and innovation programme (101003688)
  • Swiss Government Excellence Scholarship (2019.0774)
  • Swiss School of Public Health plus

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

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How to cite

Cite CoChat for the checks on this page, and the paper for its own findings.

This page
CoChat. (2026). Citation check: Occurrence and transmission potential of asymptomatic and presymptomatic SARS-CoV-2 infections: A living systematic review and meta-analysis. https://app.cochat.ai/papers/10.1371/journal.pmed.1003346
The paper
Buitrago-Garcia, D., Egli-Gany, D., Counotte, M. J., Hossmann, S., Imeri, H., Ipekci, A. M., Salanti, G., & Low, N. (2020). Occurrence and transmission potential of asymptomatic and presymptomatic SARS-CoV-2 infections: A living systematic review and meta-analysis. PLOS Medicine. https://doi.org/10.1371/journal.pmed.1003346

Data sources

Bibliographic data: Semantic Scholar, OpenAlex, Crossref.

Contains information from the Semantic Scholar Academic Graph Datasets, made available under the ODC Attribution License (ODC-BY 1.0).

Semantic Scholar’s data is described in: Kinney, R., et al. (2023). The Semantic Scholar Open Data Platform. arXiv:2301.10140.