ArticlePNAS nexus2026
Proactive vs. reactive COVID-19 screening in schools: Lessons from experimental protocols in France during the Delta and Omicron waves.
Article in PNAS nexus, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 1 paper.
What it found
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
1 citing paper in PubMed.
- Counterfactual evaluation of elementary and secondary school policies in the COVID-19 pandemic.Nature communications · 2026Article
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
5 authors.
Funding
No grant is acknowledged in the PubMed record.
Abstract
The COVID-19 pandemic prompted diverse policies to manage safety in schools, balancing transmission control with educational continuity. We evaluated an experimental weekly screening protocol through salivary PCR tests against nationally implemented reactive strategies (class closure or class screening following case detection) in 25 primary schools in the Auvergne-Rhône-Alpes region of France during the Delta (November-December 2021) and Omicron (January-February 2022) waves. We used an agent-based model of severe acute respiratory syndrome coronavirus 2 transmission in schools, parameterized with empirical contact data and fitted to observed prevalence in 18 schools selected for the analysis under variant-specific epidemiological conditions. We simulated the weekly screening following the experimental protocol, with 7-day isolation of positive cases and class closure after three detected cases. We quantified reductions in within-school transmission and student-days lost and combined efficacy. The experimental weekly screening protocol reduced within-school transmission by 40% (interquartile range [IQR] 18-53%) during the Delta wave and 39% (IQR 31-46%) during the Omicron wave, relative to reactive strategies implemented nationally. Across both waves, weekly screening without class closure achieved the greatest overall efficiency, balancing transmission reduction and educational continuity. By mitigating asymptomatic spread through a structured and predictable testing schedule, weekly screening offered operational advantages over reactive strategies. These findings explicitly quantify key trade-offs between infection control and educational continuity and inform the design of proactive school-based interventions in future pandemics.
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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.