Understanding the epidemiological characteristics of the primary healthcare corporation-based COVID-19 swabbed persons in Qatar, 2020

Background: In March 2020, Qatar started reporting increased numbers of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), causing coronavirus disease 2019 (COVID-19). National preventive measures were implemented, and a testing plan was developed to respond to the pandemic with the Primary Health Care Corporation (PHCC) as the central element. PHCC is the main public primary healthcare provider in Qatar and it operates in 27 health centers with around 1.4 million registered individuals as of January 1, 2020. The latter population was distributed across four main nationality groups; Middle Eastern and North African (51.5%), Asian (41.2%), African (2.4%), and others (5.1%). At the primary healthcare level in Qatar, this study describes the epidemiological characteristics of individuals registered at PHCC who had contracted COVID-19 in 2020 during the first wave before the vaccination phase and examines the factors associated with the positivity rate.

Methods: Retrospective data analysis was conducted for persons screened for SARS-CoV-2 in primary healthcare health centers in Qatar between March 11 and December 31, 2020. The study analyzed the demographic characteristics of the tested persons and noncommunicable disease burden, positivity rate by month, nationality, and age-group, and the factors associated with the positivity rate.

Results: Between March 11 and December 31, 2020, PHCC tested 379,247 persons for SARS-CoV-2, with a median age (IQR) of 32 (21–42) years. Of these, 57.0% were from the Middle East and North Africa, and 32.5% were originally from Asia. Overall, 10.9% had diabetes mellitus and 11.3% had hypertension. The epidemiological curve showed a steep increase in the positivity rate from March till May 2020, at the highest rate of 37.5% in May 2020. The highest positivity rate was observed among Asian males at 15.7%. The positivity rate was the lowest among the age-group aged 60 years and above. It was almost the same among the tested persons for SARS-CoV-2 in the three main age groups (0–18, 19–39, 40–59) at 10.1%, 12.3%, and 12.2%, respectively. In a multi regression model, being a male was associated with a higher risk (OR 1.15; 95% CI 1.13–1.17). Asians were at higher risk than those originally from the Middle East and North Africa (OR 1.29; 95% CI 1.27–1.32). COVID-19 infection was higher among those presenting clinical symptoms than asymptomatic individuals (OR. 4.52; 95% CI 4.42–4.64).

Conclusion: The epidemic among the PHCC-registered population predominantly affected younger ages and males, namely, coming from Asia. At the primary healthcare level, the COVID-19 infection rate was higher among those who presented with clinical symptoms. The lowest positivity rate among individuals >60 years may reflect the effectiveness of public health measures related to the high-risk group. Scaled-up testing at the primary healthcare level helped to detect more cases during the peak of the first wave and was reflected in a steady increase in the positivity rate flattened later due to the established public health measures.