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Now showing items 11-20 of 20
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 ...
Duration of immune protection of SARS-CoV-2 natural infection against reinfection.
(
Oxford University Press
, 2022 , Article)
The future of the SARS-CoV-2 pandemic hinges on virus evolution and duration of immune protection of natural infection against reinfection. We investigated duration of protection afforded by natural infection, the effect ...
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 antigen dose and SARS-CoV-2 omicron infection in adolescents
(
Elsevier
, 2023 , Other)
COVID-19 vaccine antigen dose might affect protection against SARS-CoV-2 infection,1, 2 but direct evidence to quantify this effect is absent. We conducted a matched, retrospective, cohort study using a regression ...
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 ...
Protective Effect of Previous SARS-CoV-2 Infection against Omicron BA.4 and BA.5 Subvariants.
(
Massachusetts Medical Society
, 2022 , Article)
The BA.4 and BA.5 subvariants of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) B.1.1.529 (omicron) variant have shown the capacity of escaping from neutralizing antibodies.1 These subvariants had an ...
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 ...
Turning point in COVID-19 severity and fatality during the pandemic: a national cohort study in Qatar
(
BMJ Publishing Group
, 2023 , Article)
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 ...
History of primary-series and booster vaccination and protection against Omicron reinfection
(
American Association for the Advancement of Science
, 2023 , Article)
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 ...
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 ...