SynthesisBMJ open2021
Presymptomatic transmission of SARS-CoV-2 infection: a secondary analysis using published data.
Synthesis in BMJ open, 2021. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 35 papers, 1 of them a synthesis 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.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
35 citing papers in PubMed, 1 synthesis or guideline pooled it.
- SARS-CoV-2 detection, viral load and infectivity over the course of an infection.The Journal of infection · 2020Pooled it
- 8,266 SARS-CoV-2 Genomic Assemblies from Asymptomatic Carriers in Japan.Scientific data · 2026Article
- Models for SARS-CoV-2 health policies: social distancing amid vaccination and virus variants.Royal Society open science · 2025Article
- Viral Transmission in Sea Food Systems: Strategies for Control and Emerging Challenges.Foods (Basel, Switzerland) · 2025Review
- Molecular epidemiology of SARS-CoV-2 genome sentinel surveillance in commercial COVID-19 testing sites targeting asymptomatic individuals during Japan's seventh epidemic wave.Scientific reports · 2024Article
- Infectivity of exhaled SARS-CoV-2 aerosols is sufficient to transmit covid-19 within minutes.Scientific reports · 2023Article
- Human ACE2 protein is a molecular switch controlling the mode of SARS-CoV-2 transmission.Journal of biomedical science · 2023Article
- Modeling and Global Sensitivity Analysis of Strategies to Mitigate Covid-19 Transmission on a Structured College Campus.Bulletin of mathematical biology · 2023Article
- Characterization of COVID-19 cases in the early phase (March to July 2020) of the pandemic in Kenya.Journal of global health · 2022Review
- Contribution of Testing Strategies and Contact Tracing towards COVID-19 Outbreaks Control: A Mathematical Modeling Study.Tropical medicine and infectious disease · 2022Article
- Transmission dynamics of monkeypox in the United Kingdom: contact tracing study.BMJ (Clinical research ed.) · 2022Article
- Onset and window of SARS-CoV-2 infectiousness and temporal correlation with symptom onset: a prospective, longitudinal, community cohort study.The Lancet. Respiratory medicine · 2022Article
- Empirical evidence on the efficiency of backward contact tracing in COVID-19.Nature communications · 2022Article
- Proportion of Pre-Symptomatic Transmission Events Associated with COVID-19 in South Korea.Journal of clinical medicine · 2022Article
- Rapid antigen testing for SARS-CoV-2 infection in a university setting in Ireland: Learning from a 6-week pilot study.Public health in practice (Oxford, England) · 2022Article
- Article
- Dispersion of SARS-CoV-2 in air surrounding COVID-19-infected individuals with mild symptoms.Indoor air · 2022Article
- Shorter Incubation Period among Unvaccinated Delta Variant Coronavirus Disease 2019 Patients in Japan.International journal of environmental research and public health · 2022Article
- A Telemedicine-Guided Self-Collection Approach for PCR-Based SARS-CoV-2 Testing: Comparative Study.JMIR formative research · 2022Article
- Modeling the evolution of SARS-CoV-2 under non-pharmaceutical interventions and testing.Evolution, medicine, and public health · 2022Article
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
15 authors.
Funding
No grant is acknowledged in the PubMed record.
Abstract
objectiveTo estimate the proportion of presymptomatic transmission of SARS-CoV-2 infection that can occur, and the timing of transmission relative to symptom onset. SETTING/
designSecondary analysis of international published data. DATA SOURCES: Meta-analysis of COVID-19 incubation period and a rapid review of serial interval and generation time, which are published separately.
participantsData from China, the Islamic Republic of Iran, Italy, Republic of Korea, Singapore and Vietnam from December 2019 to May 2020.
methodsSimulations were generated of incubation period and of serial interval or generation time. From these, transmission times relative to symptom onset, and the proportion of presymptomatic transmission, were estimated. OUTCOME MEASURES: Transmission time of SARS-CoV-2 relative to symptom onset and proportion of presymptomatic transmission.
resultsBased on 18 serial interval/generation time estimates from 15 papers, mean transmission time relative to symptom onset ranged from -2.6 (95% CI -3.0 to -2.1) days before infector symptom onset to 1.4 (95% CI 1.0 to 1.8) days after symptom onset. The proportion of presymptomatic transmission ranged from 45.9% (95% CI 42.9% to 49.0%) to 69.1% (95% CI 66.2% to 71.9%).
conclusionsThere is substantial potential for presymptomatic transmission of SARS-CoV-2 across a range of different contexts. This highlights the need for rapid case detection, contact tracing and quarantine. The transmission patterns that we report reflect the combination of biological infectiousness and transmission opportunities which vary according to context.
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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.