Characterizing the Qatar advanced-phase SARS-CoV-2 epidemic.

The overarching objective of this study was to provide the descriptive epidemiology of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) epidemic in Qatar by addressing specific research questions through a series of national epidemiologic studies. Sources of data were the centralized and standardized national databases for SARS-CoV-2 infection. By July 10, 2020, 397,577 individuals had been tested for SARS-CoV-2 using polymerase-chain-reaction (PCR), of whom 110,986 were positive, a positivity cumulative rate of 27.9% (95% CI 27.8-28.1%). As of July 5, case severity rate, based on World Health Organization (WHO) severity classification, was 3.4% and case fatality rate was 1.4 per 1,000 persons. Age was by far the strongest predictor of severe, critical, or fatal infection. PCR positivity of nasopharyngeal/oropharyngeal swabs in a national community survey (May 6-7) including 1,307 participants was 14.9% (95% CI 11.5-19.0%); 58.5% of those testing positive were asymptomatic. Across 448 ad-hoc testing campaigns in workplaces and residential areas including 26,715 individuals, pooled mean PCR positivity was 15.6% (95% CI 13.7-17.7%). SARS-CoV-2 antibody prevalence was 24.0% (95% CI 23.3-24.6%) in 32,970 residual clinical blood specimens. Antibody prevalence was only 47.3% (95% CI 46.2-48.5%) in those who had at least one PCR positive result, but 91.3% (95% CI 89.5-92.9%) among those who were PCR positive > 3 weeks before serology testing. Qatar has experienced a large SARS-CoV-2 epidemic that is rapidly declining, apparently due to growing immunity levels in the population.

A retrospective epidemiological study on the incidence of salmonellosis in the State of Qatar during 2004-2012.

BACKGROUND: Salmonella is a food- and water-borne pathogen that can be easily spread in a population, leading to the outbreak of salmonellosis that is caused by ingestion of mixed salads contaminated by the pathogen. Most cases occur in the late spring months and can be seen as single cases, clusters, or episodes. OBJECTIVE: The aim of this study was to describe the incidence and epidemiological characteristics of salmonellosis in the State of Qatar. METHODS: This was a retrospective, descriptive study carried out in laboratory-confirmed cases of salmonellosis during 2004-2012 from all Salmonella surveillance centers. Therapeutic records of patients who were clinically suspected of having Salmonella diseases were analyzed. Initially, cases with typhoid fever were investigated in the laboratory by means of Widal agglutination tests, while non-typhoidal Salmonella diseases were determined based on culture technique. RESULTS: The annual incident of salmonellosis cases were 12.3, 23.0, 30.3, 19.4, 15.3, 18.0, 22.7, 18.5, and 18.1 per 100,000 population in 2006-2011 and 2012, respectively. The number of salmonellosis cases was high among less than 2-year-old females and 3-year-old males. In addition, one-fourth of patients (27.7%) were Qatari when compared to other nationalities. A significant difference in age was found between Qatari (6.08 ± 12.28 years) and non-Qatari (15.04 ± 19.56 years) patients. Of the reported cases, 79.8% included the onset date of the first symptoms. Contact phone numbers were available for 94% of the cases but addresses were available for only 50.4% of cases. The time difference between onset of symptoms and diagnosis was 5.4 ± 5.7 days. The most frequent serotype reported were type b (41.9%), type d (26.9%), and type c1 (12.2%). CONCLUSION: The present surveillance data showed a high incidence of salmonellosis in Qatar that poses a serious public health problem. Special intervention and health awareness programs are required for early screening, detection, and treatment as well as for strengthening the surveillance system of salmonellosis, with special emphasis on the laboratory study of cases.