• Long-term COVID-19 booster effectiveness by infection history and clinical vulnerability and immune imprinting: a retrospective population-based cohort study 

      Hiam, Chemaitelly; Ayoub, Houssein H; Tang, Patrick; Coyle, Peter; Yassine, Hadi M; ... more authors ( 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 ...
    • Protection from previous natural infection compared with mRNA vaccination against SARS-CoV-2 infection and severe COVID-19 in Qatar: a retrospective cohort study 

      Hiam, Chemaitelly; Ayoub, Houssein H; AlMukdad, Sawsan; Coyle, Peter; Tang, Patrick; ... more authors ( 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 ...
    • Short- and longer-term all-cause mortality among SARS-CoV-2- infected individuals and the pull-forward phenomenon in Qatar: a national cohort study 

      Hiam, Chemaitelly; Faust, Jeremy Samuel; Krumholz, Harlan M.; Ayoub, Houssein H.; Tang, Patrick; ... more authors ( Elsevier , 2023 , Article)
      ObjectivesWe assessed short-, medium-, and long-term all-cause mortality risks after a primary SARS-CoV-2 infection. MethodsA national, matched, retrospective cohort study was conducted in Qatar to assess risk of all-cause ...
    • Waning effectiveness of COVID-19 vaccines 

      Hiam, Chemaitelly; Abu-Raddad, Laith J ( Elsevier , 2022 , Article)
      In The Lancet, Peter Nordström and colleagues1 report the effectiveness of several COVID-19 vaccines and different vaccine schedules against any documented SARS-CoV-2 infection and against severe COVID-19, for up to 9 ...