Duration of COVID-19 mRNA Vaccine Effectiveness against Severe Disease.

Waning immunity following administration of mRNA-based COVID-19 vaccines remains a concern for many health systems. We undertook a study to determine if recent reports of waning for severe disease could have been attributed to design-related bias by conducting a study only among those detected with a first SARS-CoV-2 infection. We used a matched case-control study design with the study base being all individuals with first infection with SARS-CoV-2 reported in the State of Qatar between 1 January 2021 and 20 February 2022.

Prevalence and determinants of symptomatic COVID-19 infection among children and adolescents in Qatar: a cross-sectional analysis of 11 445 individuals.

There is a paucity of evidence about the prevalence and risk factors for symptomatic infection among children. This study aimed to describe the prevalence of symptomatic coronavirus disease 2019 (COVID-19) and its risk factors in children and adolescents aged 0-18 years in Qatar. We conducted a cross-sectional study of all children aged 0-18 years diagnosed with COVID-19 using polymerase chain reaction in Qatar during the period 1st March to 31st July 2020.

Demographics and Epidemiology of Hepatitis B in the State of Qatar: A Five-Year Surveillance-Based Incidence Study.

: Expatriates represent >80% of Qatar's population, mostly arriving from countries in Africa and Asia that are endemic with many diseases. This increases the risk for introducing new pathogens into the country and provides a platform for maintenance of endemic pathogen circulation. Here, we report on the incidence and epidemiological characteristics of hepatitis B in Qatar between 2010 and 2014.

Concomitant outbreaks of yellow fever and hepatitis E virus in Darfur States, Sudan, 2012.

Introduction: Yellow fever (YF) is a vector-borne disease transmitted to humans by infected Aedes mosquitoes, while hepatitis E virus (HEV) is a waterborne disease that is transmitted through the fecal-oral route. Both diseases have very close clinical presentation, namely fever, jaundice, malaise, and dark urine; they differ in severity and outcome.

Methodology: In this cross-sectional, laboratory-based study, an attempt was made to measure the correlation of concomitant YF and HEV infection in Darfur States during the previous YF outbreak in 2012.

Factors associated with dengue fever IgG sero-prevalence in South Kordofan State, Sudan, in 2012: Reporting prevalence ratios.

Background: Dengue fever (DF) is a vector-borne virus transmitted to humans by infected Aedes mosquitoes. In this study, we identified the most important factors associated with the prevalence of IgG antibodies in a border state between Sudan and the new republic of South Sudan.

Objectives: To quantify the association of specific factors with the prevalence of DF IgG antibodies in Lagawa among subjects aged 16-60 years in 2012.