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Attitudes towards booster, testing and isolation, and their impact on COVID-19 response in winter 2022/2023 in France, Belgium, and Italy: a cross-sectional survey and modelling study

By Giulia de Meijere, Eugenio Valdano, Claudio Castellano, Marion Debin, Charly Kengne-Kuetche, Clément Turbelin, Harold Noël, Joshua S. Weitz, Daniela Paolotti, Lisa Hermans, Niel Hens, Vittoria Colizza 



European countries are focusing on testing, isolation, and boosting strategies to counter the 2022/2023
winter surge due to SARS-CoV-2 Omicron subvariants. However, widespread pandemic fatigue and limited
compliance potentially undermine mitigation efforts.


To establish a baseline for interventions, we ran a multicountry survey to assess respondents’ willingness to
receive booster vaccination and comply with testing and isolation mandates. Integrating survey and estimated immunity data in a branching process epidemic spreading model, we evaluated the effectiveness and costs of current
protocols in France, Belgium, and Italy to manage the winter wave.


The vast majority of survey participants (N = 4594) was willing to adhere to testing (>91%) and rapid isolation
(>88%) across the three countries. Pronounced differences emerged in the declared senior adherence to booster
vaccination (73% in France, 94% in Belgium, 86% in Italy). Epidemic model results estimate that testing and isolation
protocols would confer significant benefit in reducing transmission (17–24% reduction, from R = 1.6 to R = 1.3 in
France and Belgium, to R = 1.2 in Italy) with declared adherence. Achieving a mitigating level similar to the French
protocol, the Belgian protocol would require 35% fewer tests (from 1 test to 0.65 test per infected person) and avoid
the long isolation periods of the Italian protocol (average of 6 days vs. 11). A cost barrier to test would significantly
decrease adherence in France and Belgium, undermining protocols’ effectiveness.


Simpler mandates for isolation may increase awareness and actual compliance, reducing testing costs,
without compromising mitigation. High booster vaccination uptake remains key for the control of the winter wave

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