SynthesisPloS one2020
Proportion of asymptomatic infection among COVID-19 positive persons and their transmission potential: A systematic review and meta-analysis.
Synthesis in PloS one, 2020. The graph could read no effect estimate from its abstract, so it casts no vote on the map. It is linked to trial NCT05290792 (Use of Wearable Sensors for Early Detection and Tracking of Viral Respiratory Tract Infections), which is not on this map. Cited by 171 papers, 10 of them syntheses that pooled it.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Use of Wearable Sensors for Early Detection and Tracking of Viral Respiratory Tract Infections: The WE SENSE Study
Who cites it
171 citing papers in PubMed, 10 syntheses or guidelines pooled it, 336 citations in OpenAlex.
- Impact of disease severity, age, sex, comorbidity, and vaccination on secondary attack rates of SARS-CoV-2: a global systematic review and meta-analysis.BMC infectious diseases · 2025Pooled it
- Estimating Hidden Population Size of COVID-19 using Respondent-Driven Sampling Method - A Systematic Review.Infectious disorders drug targets · 2024Pooled it
- Comparative analysis of inflight transmission of SARS-CoV-2, influenza, and SARS-CoV-1.Epidemiology and infection · 2023Pooled it
- Evaluation of Diagnostic Strategies for Identifying SARS-CoV-2 Infection in Clinical Practice: a Systematic Review and Compliance with the Standards for Reporting Diagnostic Accuracy Studies Guideline (STARD).Microbiology spectrum · 2022Pooled it
- Antigen Detection Tests for SARS-CoV-2: a systematic review and meta-analysis on real world data.Acta bio-medica : Atenei Parmensis · 2022Pooled it
- mRNA Covid-19 vaccines in pregnancy: A systematic review.PloS one · 2022Pooled it
- Pooled it
- Global Percentage of Asymptomatic SARS-CoV-2 Infections Among the Tested Population and Individuals With Confirmed COVID-19 Diagnosis: A Systematic Review and Meta-analysis.JAMA network open · 2021Pooled it
- Non-pharmacological measures implemented in the setting of long-term care facilities to prevent SARS-CoV-2 infections and their consequences: a rapid review.The Cochrane database of systematic reviews · 2021Pooled it
- COVID-19: Critical appraisal of the evidence.Anales de pediatria · 2021Pooled it
- Tracking the evolution of biomarker efficacy in SARS-CoV-2: a global meta-analyses series.Respiratory research · 2026Article
- Key Features and Controversies of the COVID-19 Epidemic and Response in North Korea.Journal of Korean medical science · 2025Article
- Modeling the effectiveness of RT-PCR, RT-LAMP, and antigen testing strategies for COVID-19 control.BMC infectious diseases · 2025Article
- Seroprevalence of SARS-CoV-2 antibodies in Ethiopia: findings from the 2022 national population-based survey (second round).BMC infectious diseases · 2025Article
- Article
- Coronavirus disease-2019 (COVID-19) outbreak in a long-term care hospital in Korea in early 2021.Infection prevention in practice · 2025Article
- Higher frequency of interstate over international transmission chains of SARS-CoV-2 virus at the Rio Grande do Sul - Brazil state borders.Virus research · 2025Article
- Clinicopathologic discordance-a not unexpected occurrence.Forensic science, medicine, and pathology · 2024Article
- Trends in COVID-19-Attributable Hospitalizations Among Adults With Laboratory-Confirmed SARS-CoV-2-COVID-NET, June 2020 to September 2023.Influenza and other respiratory viruses · 2024Article
- Insights into SARS-CoV-2 Surveillance among Prison Populations in Mato Grosso do Sul, Brazil, in 2022.Viruses · 2024Article
111 more citing papers are in PubMed but not listed here.
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
7 authors at 2 institutions in 1 country.
Funding
No grant is acknowledged in the PubMed record.
Abstract
backgroundThe study objective was to conduct a systematic review and meta-analysis on the proportion of asymptomatic infection among coronavirus disease 2019 (COVID-19) positive persons and their transmission potential.
methodsWe searched Embase, Medline, bioRxiv, and medRxiv up to 22 June 2020. We included cohorts or cross-sectional studies which systematically tested populations regardless of symptoms for COVID-19, or case series of any size reporting contact investigations of asymptomatic index patients. Two reviewers independently extracted data and assessed quality using pre-specified criteria. Only moderate/high quality studies were included. The main outcomes were proportion of asymptomatic infection among COVID-19 positive persons at testing and through follow-up, and secondary attack rate among close contacts of asymptomatic index patients. A qualitative synthesis was performed. Where appropriate, data were pooled using random effects meta-analysis to estimate proportions and 95% confidence intervals (95% CI).
resultsOf 6,137 identified studies, 71 underwent quality assessment after full text review, and 28 were high/moderate quality and were included. In two general population studies, the proportion of asymptomatic COVID-19 infection at time of testing was 20% and 75%, respectively; among three studies in contacts it was 8.2% to 50%. In meta-analysis, the proportion (95% CI) of asymptomatic COVID-19 infection in obstetric patients was 95% (45% to 100%) of which 59% (49% to 68%) remained asymptomatic through follow-up; among nursing home residents, the proportion was 54% (42% to 65%) of which 28% (13% to 50%) remained asymptomatic through follow-up. Transmission studies were too heterogenous to meta-analyse. Among five transmission studies, 18 of 96 (18.8%) close contacts exposed to asymptomatic index patients were COVID-19 positive.
conclusionsDespite study heterogeneity, the proportion of asymptomatic infection among COVID-19 positive persons appears high and transmission potential seems substantial. To further our understanding, high quality studies in representative general population samples are required.
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Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.