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.
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
Author Information
Giulia de Meijere: Gran Sasso Science Institute (GSSI), L'Aquila, Italy.
Eugenio Valdano: Sorbonne Université, INSERM, Institut Pierre Louis d'Épidémiologie et de Santé Publique (IPLESP), Paris, France.
Claudio Castellano: Istituto dei Sistemi Complessi (ISC-CNR), Roma, Italy.
Marion Debin: Sorbonne Université, INSERM, Institut Pierre Louis d'Épidémiologie et de Santé Publique (IPLESP), Paris, France.
Charly Kengne-Kuetche: Sorbonne Université, INSERM, Institut Pierre Louis d'Épidémiologie et de Santé Publique (IPLESP), Paris, France.
Clément Turbelin: Sorbonne Université, INSERM, Institut Pierre Louis d'Épidémiologie et de Santé Publique (IPLESP), Paris, France.
Harold Noël: Santé Publique France, Saint-Maurice, France.
Joshua S Weitz: School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA.
Daniela Paolotti: ISI Foundation, Turin, Italy.
Lisa Hermans: Data Science Institute, I-biostat, Hasselt University, Hasselt, Belgium.
Niel Hens: Data Science Institute, I-biostat, Hasselt University, Hasselt, Belgium.
Vittoria Colizza: Sorbonne Université, INSERM, Institut Pierre Louis d'Épidémiologie et de Santé Publique (IPLESP), Paris, France.
Background: 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. Methods: 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. Findings: 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. Interpretation: 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. Funding: The European Commission, ANRS-Maladies Infectieuses Émergentes, the Agence Nationale de la Recherche, the Chaires Blaise Pascal Program of the Île-de-France region.
