Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2021 Feb 12;16(2):e0246903.
doi: 10.1371/journal.pone.0246903. eCollection 2021.

Epidemiological characterization of symptomatic and asymptomatic COVID-19 cases and positivity in subsequent RT-PCR tests in the United Arab Emirates

Rami H Al-Rifai  1 , Juan Acuna  2 , Farida Ismail Al Hossany  3 , Bashir Aden  3 , Shamma Abdullah Al Memari  3 , Shereena Khamis Al Mazrouei  3 , Luai A Ahmed  1
Affiliations

Epidemiological characterization of symptomatic and asymptomatic COVID-19 cases and positivity in subsequent RT-PCR tests in the United Arab Emirates

Rami H Al-Rifai et al. PLoS One. .

Abstract

The coronavirus disease 2019 (COVID-19) cases could be symptomatic or asymptomatic. We (1) characterized and analyzed data collected from the first cohort of reverse transcriptase polymerase chain reaction (RT-PCR)-confirmed COVID-19 cases reported in the Emirate of Abu Dhabi, United Arab Emirates, according to the symptomatic state, and (2) identified factors associated with the symptomatic state. The association between the symptomatic state and testing positive in three subsequent RT-PCR testing rounds was also quantified. Between February 28 and April 8, 2020, 1,249 cases were reported. Sociodemographic characteristics, working status, travel history, and chronic comorbidities of 791 cases were analyzed according to the symptomatic state (symptomatic or asymptomatic). After the first confirmatory test, the results of three subsequent tests were analyzed. The mean age of the 791 cases was 35.6 ± 12.7 years (range: 1-81). Nearly 57.0% of cases were symptomatic. The two most frequent symptoms were fever (58.0%) and cough (41.0%). Symptomatic cases (mean age 36.3 ± 12.6 years) were significantly older than asymptomatic cases (mean age 34.5 ± 12.7 years). Compared with nonworking populations, working in public places (adjusted odds ratio (aOR), 1.76, 95% confidence interval (95% CI): 1.11-2.80), healthcare settings (aOR, 2.09, 95% CI: 1.01-4.31), or in the aviation and tourism sectors (aOR, 2.24, 95% CI: 1.14-4.40) was independently associated with the symptomatic state. Reporting at least one chronic comorbidity was also associated with symptomatic cases (aOR, 1.76, 95% CI: 1.03-3.01). Compared with asymptomatic cases, symptomatic cases had a prolonged duration of viral shedding and consistent odds of ≥2 positive COVID-19 tests result out of the three subsequent testing rounds. A substantial proportion of the diagnosed COVID-19 cases in the Emirate of Abu Dhabi were asymptomatic. Quarantining asymptomatic cases, implementing prevention measures, and raising awareness among populations working in high-risk settings are warranted.

PubMed Disclaimer

Conflict of interest statement

The authors have declared that no competing interests exist.

Figures

Fig 1
Fig 1. RT-PCR-confirmed COVID-19 cases identified between February 28, 2020 and April 8, 2020 in the Emirate of Abu Dhabi.
*mean number of symptoms = 1.75 (range: 1–6 symptoms).
Fig 2
Fig 2. Distribution of symptoms among the 447 symptomatic COVID-19 cases.
Fig 3
Fig 3. Kaplan–Meier curves for the duration of viral shedding among asymptomatic and symptomatic cases.
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Zhu N, Zhang D, Wang W, Li X, Yang B, Song J, et al. A Novel Coronavirus from Patients with Pneumonia in China, 2019. N Engl J Med. 2020;382(8):727–33. 10.1056/NEJMoa2001017 - DOI - PMC - PubMed
    1. Worldometers. COVID-19 coronavirus pandemic [Internet]. [cited 2020 June 2] Available from: https://www.worldometers.info/coronavirus/#countries.
    1. World Health Organization. Coronavirus disease 2019 (COVID-19) situation report– 46 [Internet]. [cited 2020 June 1] Available from: https://www.who.int/docs/default-source/coronaviruse/situation-reports/2... = 96b04adf_4.
    1. Zou L, Ruan F, Huang M, Liang L, Huang H, Hong Z, et al. SARS-CoV-2 Viral Load in Upper Respiratory Specimens of Infected Patients. N Engl J Med. 2020;382(12):1177–9. 10.1056/NEJMc2001737 - DOI - PMC - PubMed
    1. Lee S, Kim T, Lee E, Lee C, Kim H, Rhee H, et al. Clinical course and molecular viral shedding among asymptomatic and symptomatic patients With SARS-CoV-2 infection in a community treatment center in the Republic of Korea. JAMA Intern Med. 2020. 10.1001/jamainternmed.2020.3862 - DOI - PMC - PubMed