Related Experiment Video
Updated: Nov 20, 2025
03:53
Author Spotlight: Advancements in Multiplex Detection of Respiratory Viruses
Published on: November 10, 2023
1.6K
The Proportion of SARS-CoV-2 Infections That Are Asymptomatic : A Systematic Review
1Scripps Research Translational Institute, La Jolla, California (D.P.O., E.J.T.).
Annals of Internal Medicine
|January 22, 2021
Summary
At least one-third of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections are asymptomatic. Longitudinal data indicate that most individuals who test positive without symptoms remain asymptomatic, impacting COVID-19 control strategies.
Area of Science:
- Virology and Epidemiology
- Public Health
- Infectious Disease Transmission
Background:
- Asymptomatic infection is a significant characteristic of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus responsible for coronavirus disease 2019 (COVID-19).
- The precise prevalence of asymptomatic SARS-CoV-2 infections remains uncertain, necessitating further investigation for effective public health strategies.
Purpose of the Study:
- To determine the proportion of individuals infected with SARS-CoV-2 who never exhibit symptoms.
- To provide data that can inform and potentially alter COVID-19 control strategies by accounting for asymptomatic transmission.
Main Methods:
- A comprehensive literature search was conducted across multiple databases (Google News, Google Scholar, medRxiv, PubMed) using relevant keywords such as 'antibodies,' 'asymptomatic,' 'COVID-19,' 'PCR,' 'seroprevalence,' and 'SARS-CoV-2.'
- Eligible studies included observational, descriptive, cross-sectional, and longitudinal designs involving SARS-CoV-2 nucleic acid or antibody testing.
- Data extraction focused on study design, testing methods, participant numbers, symptomatic status criteria, test results, and study settings.
Main Results:
- Sixty-one studies were identified, utilizing either PCR testing (43 studies) for current infection or antibody testing (18 studies) for current/prior infection.
- In longitudinal studies (14), approximately 75% of individuals who tested positive for SARS-CoV-2 without initial symptoms remained asymptomatic.
- High-quality nationwide serosurveys from England and Spain suggest that at least one-third of all SARS-CoV-2 infections are asymptomatic.
Conclusions:
- Available evidence indicates that a substantial proportion (at least one-third) of SARS-CoV-2 infections are asymptomatic.
- Longitudinal data reinforce that a significant majority of initially asymptomatic individuals remain so, highlighting the role of asymptomatic cases in transmission.
- COVID-19 control strategies must be adapted to incorporate the prevalence and transmission potential of asymptomatic SARS-CoV-2 infections.
More Related Videos
Related Concept Videos
01:05Single Nucleotide Polymorphisms-SNPs
17.4K
A single nucleotide polymorphism or SNP is a single nucleotide variation at a specific genomic position in a large population. It is the most prevalent type of sequence variation found in the human genome. Point mutations that occur in more than 1% of the population qualify as SNPs. These are present once every 1000 nucleotides on an average in the human genome. Replacement of a purine with another purine (A/G) or a pyrimidine with another pyrimidine (C/T) is known as a transition. In contrast,...
17.4K
01:29Bias in Epidemiological Studies
978
Biases can arise at various stages of research, from study design and data collection to analysis and interpretation. Recognizing and addressing these biases is essential to ensure the validity and reliability of epidemiological findings.Broadly speaking, biases in epidemiology fall into three main categories: selection bias, information bias, and confounding. A more detailed description of possible biases is:
978