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Routine SARS-CoV-2 testing frequency and risk of severe COVID-19: A nationwide population-based study
Laith J Abu-Raddad1, Houssein H Ayoub2, Peter Coyle3
1Infectious Disease Epidemiology Group, Weill Cornell Medicine-Qatar, Cornell University, Doha, Qatar; Department of Population Health Sciences, Weill Cornell Medicine, Cornell University, New York, New York, USA; Department of Public Health, College of Health Sciences, QU Health, Qatar University, Doha, Qatar; College of Health and Life Sciences, Hamad bin Khalifa University, Doha, Qatar.
Objectives:
This study assessed whether higher routine SARS-CoV-2 testing frequency is associated with reduced risk of severe, critical, or fatal COVID-19.
Methods:
A nationwide matched case-control study was conducted in Qatar between February 5, 2020 and December 18, 2021, comparing 10,909 severe, critical, or fatal COVID-19 cases to 98,811 controls from Qatar's population. Associations between testing frequency (three- and two-level classifications) and severe outcomes were estimated using conditional logistic regression.
Results:
Higher routine SARS-CoV-2 testing frequency was not associated with reduced odds of severe, critical, or fatal COVID-19. In the three-level classification analysis, aORs were 1.03 (95% CI, 0.97-1.10) for intermediate and 0.86 (95% CI, 0.74-1.01) for high versus low testing frequency. In the two-level classification analysis, the aOR was 0.97 (95% CI, 0.88-1.07) for high versus low testing frequency. Findings were consistent across subgroup analyses among clinically vulnerable individuals, outcome-stratified analyses by severity level, and sensitivity analyses restricted to Qatari nationals and the earliest severity episode per individual.
Conclusions:
Greater routine testing was not associated with reduced individual-level risk of progression to severe COVID-19, supporting more targeted allocation of testing resources while preserving the public health value of testing for case identification and transmission control.
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