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

Al-Rifai, R. H.; Acuna, J.; Al Hossany, F. I.; Aden, B.; Al Memari, S. A.; Al Mazrouei, S. K.; Ahemd, L. A.

Background The COVID-19 RT-PCR confirmed cases could be symptomatic or asymptomatic. In the United Arab Emirates (UAE), the identified COVID-19 RT-PCR confirmed cases are yet to be characterized. In this study, we characterized the first cohort of COVID-19 RT-PCR confirmed cases reported in the Abu Dhabi Emirate, UAE, according to symptomatic state, and identified factors associated with the symptomatic state. Also, the strength of association between the symptomatic state and testing positive in three subsequent RT-PCR testing rounds was examined and quantified. Method We analyzed data collected from the first cohort of the RT-PCR confirmed COVID-19 cases reported to the health authorities in the Abu Dhabi Emirate, UAE between February 28 and April 08, 2020. Self-reported sociodemographic, working status, travel history, and chronic comorbidities of 1,249 COVID-19 cases were analyzed according to symptomatic state (symptomatic and asymptomatic). After the first RT-PCR confirmatory test, the results of three subsequent testing rounds were also analyzed. Results A total of 791 confirmed cases with a mean age of 35.6 years (range: 1-81 years) and information on the symptomatic state were analyzed. Nearly, 56.0% were asymptomatic cases. The most frequent two symptoms were fever (58.0%) and cough (41.0%). The mean age of symptomatic (36.3 year, 12.6SD) was significantly higher than that of asymptomatic cases (34.5 year, 12.7SD). Compared to non-working populations, working in public places (aOR, 1.76, 95% CI: 1.11-2.80), healthcare settings (aOR, 2.09, 95% CI: 1.01-4.31), or in the aviation and tourism sector (aOR, 2.24, 95% CI: 1.14-4.40), were independently associated with the symptomatic state. Reporting at least one chronic comorbidity was also associated with symptomatic cases (aOR, 1.76, 5% CI: 1.03-3.01). Compared to asymptomatic, symptomatic COVID-19 cases had consistent odds of two or more of testing positive to COVID-19 in three subsequent testing rounds. Conclusions A substantial proportion of the diagnosed COVID-19 cases in the Abu Dhabi Emirate was asymptomatic. Quarantine of asymptomatic cases along with prevention measures and raising awareness of populations working in high-risk settings is warranted. Further, follow up research is needed to understand viral clearance and clinical outcomes according to the symptomatic state of the COVID-19 cases.