Differential protection against SARS-CoV-2 reinfection pre- and post-Omicron.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has rapidly evolved over short timescales, leading to the emergence of more transmissible variants such as Alpha and Delta. The arrival of the Omicron variant marked a major shift, introducing numerous extra mutations in the spike gene compared with earlier variants. These evolutionary changes have raised concerns regarding their potential impact on immune evasion, disease severity and the effectiveness of vaccines and treatments.

Challenges in diagnosing polyethylene glycol and polysorbate 80 allergies: implications for allergic reactions in COVID-19 mRNA vaccination program: experience from Qatar.

Introduction: COVID-19 vaccination has been a key intervention in reducing the severity of symptoms; however, concerns about vaccine safety, particularly regarding allergic reactions, arose early on. Healthcare workers faced the challenge of addressing these concerns to ensure safe vaccine administration. This study aimed to review the practical aspects of using allergy skin testing for COVID-19 vaccine excipients in patients with a history of allergic reactions developed following mRNA COVID-19 vaccination.

BNT162b2 Versus mRNA-1273 Vaccines: Comparative Analysis of Long-Term Protection Against SARS-CoV-2 Infection and Severe COVID-19 in Qatar.

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.

Health professionals' views and experiences of breaking bad news in the Eastern Mediterranean Region: a scoping review.

Introduction: Breaking bad news is a critical yet challenging aspect of healthcare that requires effective communication skills, empathy, and cultural sensitivity. Health professionals in the World Health Organization's (WHO) Eastern Mediterranean Region face unique cultural and social factors distinct from other parts of the world. This scoping review aims to comprehensively explore the peer-reviewed literature on the health professionals' experiences in delivering bad news within the WHO's Eastern Mediterranean Region.

Virus-Induced Host Chemokine CCL2 in COVID-19 Pathogenesis: Potential Prognostic Marker and Target of Anti-Inflammatory Strategy.

A wide variety of inflammatory mediators, mainly cytokines and chemokines, are induced during SARS CoV-2 infection. Among these proinflammatory mediators, chemokines tend to play a pivotal role in virus-mediated immunopathology. The C-C chemokine ligand 2 (CCL2), also known as monocyte chemoattractant protein-1 (MCP-1) is a potent proinflammatory cytokine and strong chemoattractant of monocytes, macrophages and CD4+ T cells bearing C-C chemokine receptor type-2 (CCR2).

Association between COVID-19 vaccination and stroke: a nationwide case-control study in Qatar.

Objective: This study investigated the association between Coronavirus Disease 2019 mRNA vaccination and stroke in Qatar.

Methods: Between December 1, 2020, and April 11, 2023, a matched case-control study was conducted to investigate the association between 3036 acute stroke cases and 3036 controls drawn from the entire population of Qatar.

Results: The adjusted odds ratio (aOR) for vaccination among cases compared to controls was 0.

Effectiveness of two and three doses of COVID-19 mRNA vaccines against infection, symptoms, and severity in the pre-omicron era: A time-dependent gradient.

Background: 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.

Protection of natural infection against reinfection with SARS-CoV-2 JN.1 variant.

Overall effectiveness of infection in preventing reinfection with SARS-CoV-2 JN.1 variant was estimated at 1.8% (95% CI: −9.

Addressing bias in the definition of SARS-CoV-2 reinfection: implications for underestimation.

Introduction: 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.

HIV case reporting and HIV treatment outcomes in Qatar.

Aim: 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).

SARS-CoV-2 infection and effects of age, sex, comorbidity, and vaccination among older individuals: A national cohort study.

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.

Turning point in COVID-19 severity and fatality during the pandemic: a national cohort study in Qatar.

Objective: To assess the evolution of COVID-19 severity and fatality in a unique setting that consistently applied, throughout the pandemic, rigorous and standardised criteria for defining severe COVID-19 outcomes.

Methods And Analysis: We conducted a national cohort study on 312 109 Qatari citizens to investigate incidence of severe, critical or fatal COVID-19 classified according to the WHO criteria between 28 February 2020 and 21 April 2023. Incidence rates for severe, critical or fatal COVID-19 were estimated during the pre-omicron phase, first omicron wave, combined phases and throughout the pandemic.

History of primary-series and booster vaccination and protection against Omicron reinfection.

Laboratory 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.

Short- and longer-term all-cause mortality among SARS-CoV-2- infected individuals and the pull-forward phenomenon in Qatar: a national cohort study.

Objectives: 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.

Seroprevalence of herpes simplex virus type 1 and type 2 among the migrant workers in Qatar.

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.

Bivalent mRNA-1273.214 vaccine effectiveness against SARS-CoV-2 omicron XBB* infections.

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.

Effects of previous infection, vaccination, and hybrid immunity against symptomatic Alpha, Beta, and Delta SARS-CoV-2 infections: an observational study.

Background: 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.

All-cause and COVID-19 mortality in Qatar during the COVID-19 pandemic.

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.