Preparing for pandemics needs a dose of public health and a booster of "complex thought" (Errare humanum est, perseverare diabolicum) Paul, E. Brown, G. W. Bell, D. /Ridde, Valéry Sturmberg, J. The COVID-19 pandemic has triggered unprecedented governmental responses worldwide, revealing weaknesses in health systems and public health policies due to lack of "complex thought" required to manage complex adaptive systems. Understanding COVID-19 response strategies' multiple effects is particularly important now that pandemic preparedness and response (PPR) is on top of the global health political agenda. Here, we adopt a complex adaptive systems approach to critically analyze the literature and draw lessons from the COVID-19 response to inform future PPR strategies. We observe that in many contexts, strategies implemented in response to COVID-19 were poorly effective, inefficient, and inequitable. We explain the limitations of these prevailing measures and propose approaches and strategies to manage pandemics arising from a "systems thinking" perspective. PPR demands the adoption of an evolving, evidenced-informed, and context-specific strategy based on comprehensive approaches reflecting the complexities of health crises. This means moving away from single-focused health security paradigms to consider the full range of health problems facing populations and adopting a package of interventions chosen via participatory and deliberative processes that are context-specific and sensitive, as well as evidence-driven, to ensure a fair balance between various pillars of pandemic responses: health promotion, non-pharmaceutical interventions, prophylaxis, vaccines, and treatments. 2024 text https://www.documentation.ird.fr/hor/fdi:010091972 fdi:010091972 Paul E., Brown G. W., Bell D., Ridde Valéry, Sturmberg J.. Preparing for pandemics needs a dose of public health and a booster of "complex thought" (Errare humanum est, perseverare diabolicum). 2024, [Early access], [10 p.] EN MONDE