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.

Knowledge, attitudes, and practices of breastfeeding among women visiting primary healthcare clinics on the island of Abu Dhabi, United Arab Emirates.

BACKGROUND: The World Health Organization recommends continued breastfeeding up to 2 years of age or beyond. This study assessed breastfeeding knowledge, attitudes, and practices among women residing on the island of Abu Dhabi and identified associated factors. METHODS: We conducted a cross-sectional study using a self-administered questionnaire among mothers visiting primary healthcare clinics in Abu Dhabi between November 2014 and 2015. Participants were women aged at least 18 years who had at least one child aged 2 years or younger at the time of the study. Breastfeeding knowledge, attitudes, and practices were assessed on the basis of experience with last child. Selected questions were used to develop a scaled scoring system to categorize these aspects as good, fair, or poor. Exclusive breastfeeding is defined as the act of feeding infants only breast milk since birth, without providing water, formula, or other liquid supplements. RESULTS: The participants were 344 women. Exclusive breastfeeding for 6 months was reported by only 46 (16.9%, 95% CI 0.10, 0.17, n = 272). 79 (28.7%, n = 275) of the participants were breastfeeding and planning to continue after the child was ≥24 months. Multivariate logistic regression analysis revealed that the following factors were associated with exclusive breastfeeding: mothers with female children (adjusted OR [AOR] 2.42; 95% CI 1.18, 4.97) and better breastfeeding knowledge scores (AOR 1.25; 95% CI 1.04, 1.50). The following factors were associated with less likelihood of exclusively breastfeeding: working mothers (AOR 0.29; 95% CI 0.12, 0.72), living with relatives (AOR 0.21; 95% CI 0.05, 0.81), no past exclusive breastfeeding experience (AOR 0.23; 95% CI 0.09, 0.58) and being offered readymade liquid formula in hospital (AOR 0.33; 95% CI 0.15, 0.72). The most common reason for stopping breastfeeding was insufficient breast milk production (68/89, 76%), and the most common work related reason was inadequate maternity leave (24/89, 15%). CONCLUSION: Although breastfeeding knowledge was generally good, breastfeeding practice was still suboptimal. Modifiable factors found to predict exclusive breastfeeding included breastfeeding knowledge and mothers' employment status.

Differential outcome of infection with attenuated Salmonella in MyD88-deficient mice is dependent on the route of administration.

Activation of the innate immune system is a prerequisite for the induction of adaptive immunity to both infectious and non-infectious agents. TLRs are key components of the innate immune recognition system and detect pathogen-associated molecular patterns. Most TLRs utilize the MyD88 adaptor for their signaling pathways. In the current study, we investigated innate and adaptive immune responses to primary as well as secondary Salmonella infections in MyD88-deficient (MyD88(-/-)) mice. Using i.p. or oral route of inoculation, we demonstrate that MyD88(-/-) mice are hypersusceptible to infection by an attenuated, double auxotrophic, mutant of Salmonella enterica serovar Typhimurium (S. typhimurium). This is manifested by 2-3 logs higher bacterial loads in target organs, delayed recruitment of phagocytic cells, and defective production of proinflammatory cytokines in MyD88(-/-) mice. Despite these deficiencies, MyD88(-/-) mice developed Salmonella-specific memory Th1 responses and produced elevated serum levels of anti-Salmonella Abs, not only of Th1-driven (IgG2c, IgG3) but also IgG1 and IgG2b isotypes. Curiously, these adaptive responses were insufficient to afford full protection against a secondary challenge with a virulent strain of S. typhimurium. In comparison with the high degree of mortality seen in MyD88(-/-) mice following i.p. inoculation, oral infections led to the establishment of a state of long-term persistence, characterized by continuous bacterial shedding in animal feces that lasted for more than 6 months, but absence from systemic organs. These findings suggest that the absent expression of MyD88 affects primarily the innate effector arm of the immune system and highlights its critical role in anti-bacterial defense.