Self-testing and vaccination against COVID-19 to minimize school closure

Abstract

Schools were largely closed in 2020-2021 to counter COVID-19 spread, impacting students’ education and well-being. With highly contagious variants expanding in Europe while vaccine hesitancy persists, safe options to maintain schools open are urgently needed. We developed an agent-based model of SARS-CoV-2 transmission in school. We used empirical contact data measured in a primary and a secondary school in France, and field estimates for adherence to screening from 683 schools during the spring 2021 wave. Examining different screening protocols, we performed a cost-benefit analysis for varying epidemic conditions and vaccination scenarios. In a partially immunized school population, weekly screening would reduce the number of cases on average by 24% in the primary and 53% in the secondary school compared to symptom-based testing alone, if R=1.3 and 50% adhered to screening. This adherence was met in primary schools (53% (95% confidence interval 21-85%)), but insufficient participation was recorded in secondary schools (10% (1-38%) in middle schools, 6% (2-12%) in high schools). Regular screening would also reduce by 90% the number of student-days lost compared to reactive class closure. No difference was predicted when fully vaccinating teachers, due to their limited number and mixing. Partially vaccinating adolescents would still require regular screening for additional control (20% case reduction with 50% vaccinated students). In the upcoming fall, COVID-19 epidemic will likely continue to pose a risk to the safe opening of schools. Increasing vaccination coverage in adolescents and implementing regular testing while largely incentivizing adherence are essential steps to keep schools open.

Minimizing school disruption under high incidence conditions due to the Omicron variant in early 2022

“…We considered the circulation of the Omicron variant, assuming 20% protection from infection from prior variants 11 , an intrinsic transmissibility advantage of 30%-80% relative to Delta 12 , and a shorter incubation period 12,13 . The advantage is applied to the within-school transmissibility of previously circulating variants that we inferred in prior work from observed prevalence in French schools 4 (SI).…”

Impact of the representation of contact data on the evaluation of interventions in infectious diseases simulations

“…Computational models and numerical simulations are essential tools for the understanding of epidemic spread [1, 2], at scales ranging from global to local [3, 4, 5, 6]. They have been used in the past to examine pandemic scenarios, and more extensively during the current COVID-19 pandemic, to evaluate the potential impact of non-pharmaceutical interventions (NPIs) ranging from international travel restrictions [5, 4, 7, 8, 9] to lockdowns or curfews aiming at reducing global mobility and interactions [10, 11, 12, 13], to more targeted measures such as isolation of positive cases, contact tracing, telework, partial closures of schools or surveillance by regular testing [14, 15, 16, 17, 18, 19, 20, 21, 22].…”

Modelling COVID-19 in school settings to evaluate prevention and control protocols

“…Studies such as ours show the huge potential of modelling for the evaluation of detailed scenarios and protocols, and thus for public health decision-making tailored to specific contexts such as schools [10] , [16] , [17] , [18] . Models can be built at different levels of realism, including different levels of details on human behaviour and interaction, depending on the available data.…”

“…To this aim, we used field data on pilot screenings at school performed in France during the 2021 spring wave due to the Alpha variant [10] , providing information on adherence to screening, and empirical data describing time-resolved face-to-face proximity contacts in a primary school in France during a pre-pandemic period, previously used to study spreading processes [11] . We developed a stochastic agent-based model of SARS-CoV-2 within-school propagation [10] , parameterised with age-specific estimates of susceptibility [12] , transmissibility [13] , probability of developing symptoms [14] , and probability to detect a case based on symptoms [7] , and considering external introduction of infected individuals in the school [10] . Using this data-driven model, we evaluated the benefits and costs of a wide range of scenarios in terms of epidemic conditions and protocols.…”

“…Higher incidence in the community and larger reproductive numbers reduce the benefit of weekly testing, thus requiring increased adherence or frequency [10] . Our results are robust against changes in detection rates, test sensitivity and relative transmissibility of children [10] .…”