During the COVID-19 pandemic, governments faced the challenge of managing population behavior to prevent their healthcare systems from collapsing. Sweden adopted a strategy centered on voluntary sanitary recommendations while Belgium resorted to mandatory measures. Their consequences on pandemic progression and associated economic impacts remain insufficiently understood. This study leverages the divergent policies of Belgium and Sweden during the COVID-19 pandemic to relax the unrealistic -- but persistently used -- assumption that social contacts are not influenced by an epidemic's dynamics. We develop an epidemiological-economic co-simulation model where pandemic-induced behavioral changes are a superposition of voluntary actions driven by fear, prosocial behavior or social pressure, and compulsory compliance with government directives. Our findings emphasize the importance of early responses, which reduce the stringency of measures necessary to safeguard healthcare systems and minimize ensuing economic damage. Voluntary behavioral changes lead to a pattern of recurring epidemics, which should be regarded as the natural long-term course of pandemics. Governments should carefully consider prolonging lockdown longer than necessary because this leads to higher economic damage and a potentially higher second surge when measures are released. Our model can aid policymakers in the selection of an appropriate long-term strategy that minimizes economic damage.

翻译：在COVID-19疫情期间，各国政府面临通过管理人口行为以防止医疗系统崩溃的挑战。瑞典采取了以自愿性卫生建议为中心的策略，而比利时则采取了强制性措施。这些措施对疫情发展及相关经济影响的认识仍不充分。本研究利用比利时和瑞典在COVID-19疫情期间差异化的政策，以放宽一个不切实际但持续使用的假设——即社会接触不受流行病动态的影响。我们开发了一个流行病-经济协同模拟模型，其中疫情引发的行为变化是恐惧、亲社会行为或社会压力驱动的自愿行动，以及遵守政府指令的强制合规行为的叠加。我们的研究结果强调了早期应对的重要性，这可以减轻保护医疗系统所需措施的严格程度，并最小化随之而来的经济损失。自愿性行为变化会导致周期性疫情模式，这应被视为大流行病的自然长期进程。各国政府应谨慎避免将封锁延长至超出必要时间，因为这会增加经济损失，并在措施解除时可能导致更严重的第二波疫情高峰。我们的模型可以帮助政策制定者选择合适的长远策略，以最小化经济损失。