Browsing Mathematics, Statistics & Physics by Author "Chemaitelly, Hiam"

Now showing items 1-20 of 29

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

      Chemaitelly, Hiam; Ayoub, Houssein H.; Tang, Patrick; Yassine, Hadi M.; Al Thani, Asmaa A.; ... more authors ( Frontiers Media , 2024 , Article)
      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 ...

    • Assessment of the Risk of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Reinfection in an Intense Reexposure Setting 

      Abu-Raddad, Laith J.; Chemaitelly, Hiam; Malek, Joel A.; Ahmed, Ayeda A.; Mohamoud, Yasmin A.; ... more authors ( NLM (Medline) , 2021 , Article)
      BACKGROUND: Risk of reinfection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is unknown. We assessed the risk and incidence rate of documented SARS-CoV-2 reinfection in a cohort of laboratory-confirmed ...

    • BNT162b2 antigen dose and SARS-CoV-2 omicron infection in adolescents 

      Chemaitelly, Hiam; Ayoub, Houssein H.; Coyle, Peter; Tang, Patrick; Yassine, Hadi M.; ... more authors ( 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 ...

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

      Chemaitelly, Hiam; Ayoub, Houssein H; Coyle, Peter; Tang, Patrick; Hasan, Mohammad R; ... more authors ( Wiley , 2024 , Article)
      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 ...

    • Characterizing the effective reproduction number during the COVID-19 pandemic: Insights from Qatar's experience 

      Bsat, Raghid; Chemaitelly, Hiam; Coyle, Peter; Tang, Patrick; Hasan, Mohammad R.; ... more authors ( Edinburgh University Global Health Society , 2022 , Article)
      Background The effective reproduction number, Rt, is a tool to track and understand pandemic dynamics. This investigation of Rt estimations was conducted to guide the national COVID-19 response in Qatar, from the onset of ...

    • Comparative analysis and evolution of civilian versus combatant mortality ratios in Israel-Gaza conflicts, 2008–2023 

      Ayoub, Houssein H.; Chemaitelly, Hiam; Abu-Raddad, Laith J. ( Frontiers Media SA , 2024 , Article)
      Background: There is a need for statistical methodologies that scrutinize civilian casualties in conflicts, evaluating the degree to which the conduct of war affects civilians and breaches the laws of war. Employing an ...

    • Covid-19 Vaccine Protection among Children and Adolescents in Qatar. 

      Chemaitelly, Hiam; AlMukdad, Sawsan; Ayoub, Houssein H; Altarawneh, Heba N; Coyle, Peter; ... more authors ( Massachusetts Medical Society , 2022 , Article)
      The BNT162b2 vaccine against coronavirus disease 2019 (Covid-19) has been authorized for use in children 5 to 11 years of age and adolescents 12 to 17 years of age but in different antigen doses. We assessed the real-world ...

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

      Chemaitelly, Hiam; Ayoub, Houssein H.; Coyle, Peter; Tang, Patrick; Hasan, Mohammad R.; ... more authors ( Springer Nature , 2025 , Article)
      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 Delta1, 2–3. The arrival of the Omicron ...

    • Duration of immune protection of SARS-CoV-2 natural infection against reinfection. 

      Chemaitelly, Hiam; Nagelkerke, Nico; Ayoub, Houssein H; Coyle, Peter; Tang, Patrick; ... more authors ( 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 ...

    • Duration of mRNA vaccine protection against SARS-CoV-2 Omicron BA.1 and BA.2 subvariants in Qatar. 

      Chemaitelly, Hiam; Ayoub, Houssein H; AlMukdad, Sawsan; Coyle, Peter; Tang, Patrick; ... more authors ( Nature Research , 2022 , Article)
      SARS-CoV-2 Omicron BA.1 and BA.2 subvariants are genetically divergent. We conducted a matched, test-negative, case-control study to estimate duration of protection of the second and third/booster doses of mRNA COVID-19 ...

    • Dynamics of Neisseria gonorrhoeae transmission among female sex workers and clients: A mathematical modeling study 

      Houssein H., Ayoub; Tomy, Milan; Chemaitelly, Hiam; Omori, Ryosuke; Buse, Kent; ... more authors ( Elsevier , 2024 , Article)
      BackgroundThis study aimed to examine the transmission dynamics of Neisseria gonorrhoeae (NG) in heterosexual sex work networks (HSWNs) and the impact of variation in sexual behavior and interventions on NG epidemiology. ...

    • Effect of mRNA Vaccine Boosters against SARS-CoV-2 Omicron Infection in Qatar. 

      Abu-Raddad, Laith J; Chemaitelly, Hiam; Ayoub, Houssein H; AlMukdad, Sawsan; Yassine, Hadi M; ... more authors ( Massachusetts Medical Society , 2022 , Article)
      Waning of vaccine protection against coronavirus disease 2019 (Covid-19) and the emergence of the omicron (or B.1.1.529) variant of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have led to expedited ...

    • 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 

      Layan, Sukik; Chemaitelly, Hiam; Ayoub, Houssein H.; Coyle, Peter; Tang, Patrick; ... more authors ( Elsevier , 2024 , Article)
      BackgroundVaccines 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 ...

    • Effects of BA.1/BA.2 subvariant, vaccination, and prior infection on infectiousness of SARS-CoV-2 omicron infections. 

      Qassim, Suelen H; Chemaitelly, Hiam; Ayoub, Houssein H; AlMukdad, Sawsan; Tang, Patrick; ... more authors ( 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 ...

    • Effects of Previous Infection and Vaccination on Symptomatic Omicron Infections. 

      Altarawneh, Heba N; Chemaitelly, Hiam; Ayoub, Houssein H; Tang, Patrick; Hasan, Mohammad R; ... more authors ( Massachusetts Medical Society , 2022 , Article)
      The protection conferred by natural immunity, vaccination, and both against symptomatic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection with the BA.1 or BA.2 sublineages of the omicron (B.1.1.529) ...

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

      Heba N., Altarawneh; Chemaitelly, Hiam; Ayoub, Houssein H.; Tang, Patrick; Hasan, Mohammad R.; ... more authors ( Elsevier , 2023 , Article)
      BackgroundProtection 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 ...

    • Effects of SARS-CoV-2 Alpha, Beta, and Delta variants, age, vaccination, and prior infection on infectiousness of SARS-CoV-2 infections 

      Qassim, Suelen H.; Hasan, Mohammad R.; Tang, Patrick; Chemaitelly, Hiam; Ayoub, Houssein H.; ... more authors ( 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 ...

    • Estimates of global SARS-CoV-2 infection exposure, infection morbidity, and infection mortality rates in 2020 

      Houssein H., Ayoub; Mumtaz, Ghina R.; Seedat, Shaheen; Makhoul, Monia; Chemaitelly, Hiam; ... more authors ( Elsevier , 2021 , Article)
      We aimed to estimate, albeit crudely and provisionally, national, regional, and global proportions of respective populations that have been infected with SARS-CoV-2 in the first year after the introduction of this virus ...

    • Estimating protection afforded by prior infection in preventing reinfection: Applying the test-negative study design. 

      Ayoub, Houssein H; Tomy, Milan; Chemaitelly, Hiam; Altarawneh, Heba N; Coyle, Peter; ... more authors ( 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 ...

    • Evaluating Hospital Admission Data as Indicators of COVID-19 Severity: A National Assessment in Qatar. 

      Sukik, Layan; Chemaitelly, Hiam; Ayoub, Houssein H; Coyle, Peter; Tang, Patrick; ... more authors ( Oxford University Press , 2025 , Article)
      Accurately assessing SARS-CoV-2 infection severity is essential for understanding the health impact of the infection and evaluating the effectiveness of interventions. This study investigated whether SARS-CoV-2-associated ...