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Now showing items 11-20 of 34
Protection of Omicron sub-lineage infection against reinfection with another Omicron sub-lineage
(
Nature Research
, 2022 , Article)
There is significant genetic distance between SARS-CoV-2 Omicron (B.1.1.529) variant BA.1 and BA.2 sub-lineages. This study investigates immune protection of infection with one sub-lineage against reinfection with the other ...
Protection from previous natural infection compared with mRNA vaccination against SARS-CoV-2 infection and severe COVID-19 in Qatar: a retrospective cohort study
(
Elsevier
, 2022 , Article)
BackgroundUnderstanding protection conferred by natural SARS-CoV-2 infection versus COVID-19 vaccination is important for informing vaccine mandate decisions. We compared protection conferred by natural infection versus ...
BNT162b2 and mRNA-1273 COVID-19 vaccine effectiveness against the SARS-CoV-2 Delta variant in Qatar.
(
Nature Researc
, 2021 , Article)
With the global expansion of the highly transmissible SARS-CoV-2 Delta (B.1.617.2) variant, we conducted a matched test-negative case-control study to assess the real-world effectiveness of COVID-19 messenger RNA vaccines ...
Effects of SARS-CoV-2 Alpha, Beta, and Delta variants, age, vaccination, and prior infection on infectiousness of SARS-CoV-2 infections
(
Frontiers Media
, 2022 , Article)
In 2021, Qatar experienced considerable incidence of SARS-CoV-2 infection that was dominated sequentially by the Alpha, Beta, and Delta variants. Using the cycle threshold (Ct) value of an RT-qPCR-positive test to proxy ...
Effects of BA.1/BA.2 subvariant, vaccination, and prior infection on infectiousness of SARS-CoV-2 omicron infections.
(
Oxford University Press
, 2022 , Article)
Compared to BA.1, BA.2 was associated with lower RT-qPCR cycle threshold (Ct) value-3.53 fewer cycles (95% CI: 3.46-3.60), signifying higher infectiousness. This may reflect higher viral load and/or longer duration of ...
Population immunity of natural infection, primary-series vaccination, and booster vaccination in Qatar during the COVID-19 pandemic: an observational study
(
Elsevier
, 2023 , Article)
BackgroundWaning of natural infection protection and vaccine protection highlight the need to evaluate changes in population immunity over time. Population immunity of previous SARS-CoV-2 infection or of COVID-19 vaccination ...
Estimating protection afforded by prior infection in preventing reinfection: Applying the test-negative study design.
(
Oxford University Press
, 2023 , Article)
The COVID-19 pandemic has highlighted the need to use infection testing databases to rapidly estimate effectiveness of prior infection in preventing reinfection ($P{E}_S$) by novel SARS-CoV-2 variants. Mathematical modeling ...
Long-term COVID-19 booster effectiveness by infection history and clinical vulnerability and immune imprinting: a retrospective population-based cohort study
(
Elsevier
, 2023 , Article)
BackgroundLong-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 ...
mRNA-1273 COVID-19 vaccine effectiveness against the B.1.1.7 and B.1.351 variants and severe COVID-19 disease in Qatar
(2021 , Article)
The SARS-CoV-2 pandemic continues to be a global health concern. The mRNA-1273 (Moderna) vaccine was reported to have an efficacy of 94.1% at preventing symptomatic COVID-19 due to infection with ‘wild-type’ variants in a ...
Fecal Carriage and Molecular Characterization of Carbapenemase-Producing Enterobacterales in the Pediatric Population in Qatar
(
American Society for Microbiology
, 2021 , Article)
Whole-genome sequencing was used to characterize carbapenemase-producing Enterobacterales (CPE) strains recovered from rectal screening swab samples obtained from children at a tertiary-care pediatric hospital in Qatar ...