Background: This study provides a head-to-head comparison of the protection provided by the BNT162b2 and mRNA-1273 vaccines against SARS-CoV-2 infection and against severe COVID-19, covering primary series and third dose/booster vaccinations over up to 3 years of follow-up, both before and after the emergence of the omicron variant.
Methods: Two national, matched, retrospective cohort studies were conducted on Qatar's vaccinated population from December 16, 2020, to February 18, 2024. Subgroup analyses by pre-vaccination SARS-CoV-2 infection history, as well as sensitivity analyses, were also conducted.
Background Coronavirus disease (COVID-19) is a highly infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and it has resulted in a global pandemic. The COVID-19 pandemic has resulted in numerous reports on clinical outcomes and risk factors associated with morbidity and mortality. However, the extent to which nationality influences the severity of COVID-19 is not fully understood.
View Article and Find Full Text PDFBackground: Vaccines were developed and deployed to combat severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. This study aimed to characterize patterns in the protection provided by the BNT162b2 and mRNA-1273 mRNA vaccines against a spectrum of SARS-CoV-2 infection symptoms and severities.
Methods: A national, matched, test-negative, case-control study was conducted in Qatar between January 1 and December 18, 2021, utilizing a sample of 238,896 PCR-positive tests and 6,533,739 PCR-negative tests.
Overall effectiveness of infection in preventing reinfection with SARS-CoV-2 JN.1 variant was estimated at 1.8% (95% CI: −9.
View Article and Find Full Text PDFIntroduction: Reinfections are increasingly becoming a feature in the epidemiology of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. However, accurately defining reinfection poses methodological challenges. Conventionally, reinfection is defined as a positive test occurring at least 90 days after a previous infection diagnosis.
View Article and Find Full Text PDFBackground: The human papilloma virus is a global problem that affects sexually active women and men, with cervical cancer being the most serious associated disease. Most cervical cancer cases can be prevented by vaccination against the human papilloma virus early in life. The objective of this study was to assess the knowledge, attitudes, and practices among physicians working in Qatar, regarding the human papilloma virus, infection, and prevention using vaccines.
View Article and Find Full Text PDFIn the last few decades, indoor air quality (IAQ) has become a major threat to public health. It is the fifth leading cause of premature death globally. It has been estimated that people spend ∼90 % of their time in an indoor environment.
View Article and Find Full Text PDFThe WHO member states endorsed the goal to eliminate mother-to-child transmission (EMTCT) of hepatitis B virus (HBV) by 2030, which requires achievement of ≥ 90% coverage with timely hepatitis B birth dose (HepB-BD), three doses of the hepatitis B vaccine (HepB3), and a hepatitis B surface antigen (HBsAg) seroprevalence ≤ 0.1% in children. We assessed the progress made to achieve EMTCT of HBV in Gulf Cooperation Council (GCC) countries.
View Article and Find Full Text PDFAim: The aim of the paper is to provide an overview of available HIV case reporting and treatment data for in Qatar for the period 2015-2020.
Methods: HIV case reporting data were analyzed by sex and mode of transmission. To construct HIV care continuum from the data available, we obtained information on the total number of HIV diagnosed patients on antiretroviral treatment (ART) between January 1st 2015 and December 31st 2020, number of patients on ART who had an HIV viral load test and the number who were virally suppressed (defined as having the viral load of less than 1,000 copies/mL).
Background: We investigated the contribution of age, coexisting medical conditions, sex, and vaccination to incidence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and of severe, critical, or fatal COVID-19 in older adults since pandemic onset.
Methods: A national retrospective cohort study was conducted in the population of Qatar aged ≥50 years between February 5, 2020 and June 15, 2023. Adjusted hazard ratios (AHRs) for infection and for severe coronavirus disease 2019 (COVID-19) outcomes were estimated through Cox regression models.
There is inconclusive evidence whether pregnancy exacerbates COVID-19 symptoms or not, and scarce data from the Middle East and North Africa region. The aim of this study was to investigate the association between pregnancy and COVID-19 symptoms in Qatar. This cross-sectional study was carried out using data of all women with confirmed COVID-19, comparing women of child-bearing age (18-49 years).
View Article and Find Full Text PDFLaboratory evidence suggests a possibility of immune imprinting for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. We investigated the differences in the incidence of SARS-CoV-2 reinfection in a cohort of persons who had a primary Omicron infection, but different vaccination histories using matched, national, retrospective, cohort studies. Adjusted hazard ratio for reinfection incidence, factoring adjustment for differences in testing rate, was 0.
View Article and Find Full Text PDFObjectives: We assessed short-, medium-, and long-term all-cause mortality risks after a primary SARS-CoV-2 infection.
Methods: A national, matched, retrospective cohort study was conducted in Qatar to assess risk of all-cause mortality in the national SARS-CoV-2 primary infection cohort compared with the national infection-naïve cohort. Associations were estimated using Cox proportional-hazards regression models.
Background: Limited data exists on herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) infections in migrant populations. This study investigated HSV-1 and HSV-2 seroprevalences and associations among craft and manual workers (CMWs) in Qatar who constitute 60% of Qatar's population.
Methods: A national population-based cross-sectional seroprevalence survey was conducted on the CMW population, all men, between July 26 and September 9, 2020.
Effectiveness of the 50-μg mRNA-1273.214 bivalent vaccine against SARS-CoV-2 infection was modest at 25% in a matched, retrospective, cohort study in Qatar comparing infection incidence in the bivalent cohort to that in the national no-recent-vaccination resident cohort. XBB* immune evasion, immune imprinting effects, or both, may explain findings.
View Article and Find Full Text PDFBackground: Protection against SARS-CoV-2 symptomatic infection and severe COVID-19 of previous infection, mRNA two-dose vaccination, mRNA three-dose vaccination, and hybrid immunity of previous infection and vaccination were investigated in Qatar for the Alpha, Beta, and Delta variants.
Methods: Six national, matched, test-negative, case-control studies were conducted between January 18 and December 18, 2021 on a sample of 239,120 PCR-positive tests and 6,103,365 PCR-negative tests.
Findings: Effectiveness of previous infection against Alpha, Beta, and Delta reinfection was 89.
Objective: To investigate all-cause mortality, COVID-19 mortality and all-cause non-COVID-19 mortality in Qatar during the COVID-19 pandemic.
Methods: A national, retrospective cohort analysis and national, matched, retrospective cohort studies were conducted between 5 February 2020 and 19 September 2022.
Results: There were 5025 deaths during a follow-up time of 5 247 220 person-years, of which 675 were COVID-19 related.
Background: Since the emergence of the COVID-19 pandemic, vaccines have been developed to tackle the disease. However, many people worldwide were not confident enough to take the vaccines. Developing a questionnaire to measure COVID-19 vaccine hesitancy will give the health authorities and policymakers a clear picture to establish appropriate interventions addressing vaccine hesitancy among the community.
View Article and Find Full Text PDFThere is limited seroepidemiological evidence on the magnitude and long-term durability of antibody titers of mRNA and non-mRNA vaccines in the Qatari population. This study was conducted to generate evidence on long-term anti-S IgG antibody titers and their dynamics in individuals who have completed a primary COVID-19 vaccination schedule. A total of 300 male participants who received any of the following vaccines BNT162b2/Comirnaty, mRNA-1273, ChAdOx1-S/Covishield, COVID-19 Vaccine Janssen/Johnson, or BBIBP-CorV or Covaxin were enrolled in our study.
View Article and Find Full Text PDFBackground: Long-term effectiveness of COVID-19 mRNA boosters in populations with different previous infection histories and clinical vulnerability profiles is inadequately understood. We aimed to investigate the effectiveness of a booster (third dose) vaccination against SARS-CoV-2 infection and against severe, critical, or fatal COVID-19, relative to that of primary-series (two-dose) vaccination over a follow-up duration of 1 year.
Methods: This observational, matched, retrospective, cohort study was done on the population of Qatar in people with different immune histories and different clinical vulnerability to infection.