Seroprevalence of COVID-19 infection in the Emirate of Abu Dhabi, United Arab Emirates: a population-based cross-sectional study

Background

The United Arab Emirates (UAE) was the first country in the Middle East to report severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Serosurveys are essential to understanding the extent of virus transmission. This cross-sectional study aims to assess the seroprevalence of SARS-CoV-2 infection in the Emirate of Abu Dhabi.

Methods

Between 19 July and 14 August 2020, 4487 households were selected using a random sample stratified by region and citizenship of the head of household (UAE citizen or non-citizen). A cluster sample of 40 labour camps was selected. Data on socio-demographic characteristics, risk factors and symptoms compatible with coronavirus disease 2019 (COVID-19) were collected. Each participant was first tested by Roche Elecsys^® Anti-SARS-CoV-2 assay, followed, when reactive, by the LIAISON^® SARS-CoV-2 S1/S2 IgG assay.

Results

Among 8831 individuals from households, seroprevalence was 10·4% [95% confidence intervals (CIs) 9·5–11·4], with higher seroprevalence in Abu Dhabi and Al Ain regions compared with those in Al Dhafra. In households, we found no sex difference and UAE citizens had lower seroprevalence compared with those of other nationalities. Among 4855 workers residing in labour camps, seroprevalence was 68·6% (95% CI 61·7–74·7), with higher seroprevalence among workers from Southeast Asia. In households, individuals with higher body mass indexes demonstrated higher seroprevalences than individuals with normal weight. Anosmia and ageusia were strongly associated with seropositivity.

Conclusions

The majority of household populations in the Emirate of Abu Dhabi remained unexposed to SARS-CoV-2. In labour camps, SARS-CoV-2 transmission was high. Effective public health measures should be maintained.

Prevalence of pulmonary tuberculosis among expatriates subjected to medical visa screening in Abu Dhabi, United Arab Emirates

Introduction: All applicants for work and/or residence in Abu Dhabi are screened for tuberculosis at the time of issuing or renewing their residence visa. The purpose of this study is to assess the prevalence of TB among visa applicants and the likelihood of testing positive among different subgroups.

Methods: Data from the electronic visa screening system was used for a total of 948,504 applicants screened for residence in Abu Dhabi from January to December 2010.

Results: The screening identified 4577 suspected cases of pulmonary tuberculosis (PTB); 1558 people with chest X-ray findings suggestive of prior PTB; 235 smear-positives; and 132 culture-positive cases. The prevalence of active PTB was 39/100,000, with new applicants significantly more likely to test positive compared with renewals (OR: 2.05, 95% CI: 1.5–2.7, P < .001). People coming from African countries had the highest prevalence of TB compared with people from other regions (OR: 21.25, 95% CI: 6.72–67.17, P < .001).

Conclusion: The number of active PTB cases among applicants for visa screening is still of a real concern. Without a rigorous screening system, the disease can spread to the community and hit other people. Certain subgroups were more likely to have the disease; this could provide the scientific foundation for future amendments in the screening requirements.