• Analytic comparison between three high-throughput commercial SARS-CoV-2 antibody assays reveals minor discrepancies in a high-incidence population 

      Nasrallah, Gheyath K; Dargham, Soha R; Shurrab, Farah; Al-Sadeq, Duaa W; Al-Jighefee, Hadeel; ... more authors ( Nature Research , 2021 , Article)
      Performance of three automated commercial serological IgG-based assays was investigated for assessing SARS-CoV-2 "ever" (past or current) infection in a population-based sample in a high exposure setting. PCR and serological ...
    • Association of Prior SARS-CoV-2 Infection With Risk of Breakthrough Infection Following mRNA Vaccination in Qatar. 

      Abu-Raddad, Laith J; Chemaitelly, Hiam; Ayoub, Houssein H; Yassine, Hadi M; Benslimane, Fatiha M; ... more authors ( American Medical Association , 2021 , Article)
      The effect of prior SARS-CoV-2 infection on vaccine protection remains poorly understood. To assess protection from SARS-CoV-2 breakthrough infection after mRNA vaccination among persons with vs without prior SARS-CoV-2 ...
    • BNT162b2 and mRNA-1273 COVID-19 vaccine effectiveness against the SARS-CoV-2 Delta variant in Qatar. 

      Tang, Patrick; Hasan, Mohammad R; Chemaitelly, Hiam; Yassine, Hadi M; Benslimane, Fatiha M; ... more authors ( 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 ...
    • 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 ( International Society of Global Health , 2022 , Article)
      Background: The effective reproduction number, Rt, is a tool to track and understand epidemic dynamics. This investigation of Rt estimations was conducted to guide the national COVID-19 response in Qatar, from the onset ...
    • 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 ...
    • 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 ...
    • Epidemiological impact of prioritising SARS-CoV-2 vaccination by antibody status: Mathematical modelling analyses 

      Ayoub, H.H.; Ayoub, Houssein H.; Chemaitelly, Hiam; Makhoul, Monia; Al Kanaani, Zaina; ... more authors ( BMJ Publishing Group , 2021 , Article)
      Background Vaccines against SARS-CoV-2 have been developed, but their availability falls far short of global needs. This study aimed to investigate the impact of prioritising available doses on the basis of recipient ...
    • mRNA-1273 COVID-19 vaccine effectiveness against the B.1.1.7 and B.1.351 variants and severe COVID-19 disease in Qatar 

      Chemaitelly, Hiam; Yassine, Hadi M.; Benslimane, Fatiha M.; Al Khatib, Hebah A.; Tang, Patrick; ... more authors (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 ...
    • Pfizer-BioNTech mRNA BNT162b2 Covid-19 vaccine protection against variants of concern after one versus two doses. 

      Abu-Raddad, Laith J; Chemaitelly, Hiam; Yassine, Hadi M; Benslimane, Fatiha M; Al Khatib, Hebah A; ... more authors ( Oxford University Press , 2021 , Article)
      Strategies for rolling out vaccination against Coronavirus Disease 2019 (Covid-19) varied across countries. A key question is whether delaying administration of the second vaccine dose to vaccinate the largest number of ...
    • Relative infectiousness of SARS-CoV-2 vaccine breakthrough infections, reinfections, and primary infections. 

      Abu-Raddad, Laith J; Chemaitelly, Hiam; Ayoub, Houssein H; Tang, Patrick; Coyle, Peter; ... more authors ( Springer , 2022 , Article)
      SARS-CoV-2 breakthrough infections in vaccinated individuals and in those who had a prior infection have been observed globally, but the transmission potential of these infections is unknown. The RT-qPCR cycle threshold ...
    • SARS-CoV-2 antibody-positivity protects against reinfection for at least seven months with 95% efficacy 

      Laith J., Abu-Raddad; Chemaitelly, Hiam; Coyle, Peter; Malek, Joel A.; Ahmed, Ayeda A.; ... more authors ( Elsevier , 2021 , Article)
      BackgroundReinfection with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been documented, raising public health concerns. SARS-CoV-2 reinfections were assessed in a cohort of antibody-positive persons ...
    • SARS-CoV-2 Infection Is at Herd Immunity in the Majority Segment of the Population of Qatar. 

      Al-Thani, Mohamed H; Farag, Elmoubasher; Bertollini, Roberto; Al Romaihi, Hamad Eid; Abdeen, Sami; ... more authors ( Oxford University Press , 2021 , Article)
      Qatar experienced a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) epidemic that disproportionately affected the craft and manual worker (CMW) population, who comprise 60% of the total population. This study ...
    • SARS-CoV-2 seroprevalence in the urban population of Qatar: An analysis of antibody testing on a sample of 112,941 individuals 

      Peter V., Coyle; Chemaitelly, Hiam; Ben Hadj Kacem, Mohamed Ali; Abdulla Al Molawi, Naema Hassan; El Kahlout, Reham Awni; ... more authors ( Elsevier , 2021 , Article)
      The study objective was to the assess level of detectable severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies in the urban population of Qatar. Antibody testing was performed on residual blood specimens ...
    • Severity, criticality, and fatality of the SARS-CoV-2 Beta variant 

      Abu-Raddad, Laith J; Chemaitelly, Hiam; Ayoub, Houssein H; Yassine, Hadi M; Benslimane, Fatiha M; ... more authors ( Oxford Academic , 2021 , Article)
      Beta (B.1.351) variant COVID-19 disease was investigated in Qatar. Compared to Alpha (B.1.1.7) variant, odds of progressing to severe disease were 1.24-fold (95% CI: 1.11-1.39) higher for Beta. Odds of progressing to ...
    • Two prolonged viremic SARS-CoV-2 infections with conserved viral genome for two months 

      Laith J., Abu-Raddad; Chemaitelly, Hiam; Malek, Joel A.; Ahmed, Ayeda A.; Mohamoud, Yasmin A.; ... more authors ( Elsevier , 2021 , Article)
      We document two cases of viremic and prolonged active infection with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) where the viral genome was conserved for two months, but infection was with little or ...