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. 2020 Sep:98:372-380.
doi: 10.1016/j.ijid.2020.06.098. Epub 2020 Jul 2.

The incidence of the novel coronavirus SARS-CoV-2 among asymptomatic patients: A systematic review

Duaa W Al-Sadeq  1 , Gheyath K Nasrallah  2
Affiliations

The incidence of the novel coronavirus SARS-CoV-2 among asymptomatic patients: A systematic review

Duaa W Al-Sadeq et al. Int J Infect Dis. 2020 Sep.

Abstract

Background: The recent outbreak of the coronavirus disease 2019 (COVID-19) has quickly spread globally since its discovery in Wuhan, China, in December 2019. A comprehensive strategy - including surveillance, diagnostics, research, and clinical treatment - is urgently needed to win the battle against COVID-19. Recently, numerous studies have reported the incidence of SARS-CoV-2 in asymptomatic patients. Yet, the incidence and viral transmission from the asymptomatic cases are not yet apparent.

Aim: To estimate the incidence of COVID-19 among asymptomatic cases and describe its epidemiological and clinical significance this review systematically examined the published literature on SARS-CoV-2 in asymptomatic patients.

Methods: The literature was searched through four scientific databases: PubMed, Web of Science, Scopus, and Science Direct.

Results: Sixty-three studies satisfied the inclusion criteria. The majority of the reported studies were from China. However, there was a lack of SARS-CoV-2 epidemiological studies, from several countries worldwide, tracing the actual incidence of COVID-19, especially in asymptomatic patients. Studies with a large sample size (>1000) estimated that the percentage of people contracting SARS-CoV-2 and likely to be asymptomatic ranged from 1.2-12.9%. However, other studies with a smaller sample size reported a much higher incidence and indicated that up to 87.9% of COVID-19 infected individuals could be asymptomatic. Most of these studies indicated that asymptopatics are a potential source of infection to the community.

Conclusion: This review highlighted the need for more robust and well-designed studies to better estimate COVID-19 incidence among asymptomatic patients worldwide. Early identification of asymptomatic cases, as well as monitoring and tracing close contacts, could help in mitigating the spread of COVID-19.

Keywords: Asymptomatic carrier; COVID-19; Incidence; SARS-CoV-2; Viruses.

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Figures

Figure 1
Figure 1
Flow diagram of the search strategy and article selection.
See this image and copyright information in PMC

References

    1. Al Kahlout R.A., Nasrallah G.K., Farag E.A., Wang L., Lattwein E., Müller M.A. Comparative serological study for the prevalence of anti-MERS coronavirus antibodies in high-and low-risk groups in Qatar. J Immunol Res. 2019 - PMC - PubMed
    1. Albano D., Bertagna F., Bertoli M., Bosio G., Lucchini S., Motta F. Incidental findings suggestive of covid-19 in asymptomatic patients undergoing nuclear medicine procedures in a high prevalence region. J Nucl Med. 2020 - PubMed
    1. Al-Tawfiq J.A., Gautret P. Asymptomatic Middle East Respiratory Syndrome Coronavirus (MERS-CoV) infection: extent and implications for infection control: a systematic review. Travel Med Infect Dis. 2019;27:27–32. - PMC - PubMed
    1. Amanat F. A serological assay to detect SARS-CoV-2 seroconversion in humans. Nature Med. 2020:1–4. - PMC - PubMed
    1. Amorim Filho L., Szwarcwald C.L., Mateos S.D.O.G., de Leon A.C.M.P., de Andrade Medronho R., Veloso V.G. SciELO; 2020. Seroprevalence of IgG and IgM anti-SARS-CoV-2 among voluntary blood donors in Rio de Janeiro, Brazil. - PMC - PubMed

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