This rapid scoping review has informed the development of the November 2020 United Nations Research Roadmap for the COVID-19 Recovery, by providing a synthesis of available evidence on the impact of pandemics and epidemics on (1) essential services and (2) health systems preparedness and strengthening. Emerging findings point to existing disparities in health systems and services being further exacerbated, with marginalized populations and low- and middle-income countries burdened disproportionately. More broadly, there is a need to further understand short- and long-term impacts of bypassed essential services, quality assurance of services, the role of primary health care in the frontline, and the need for additional mechanisms for effective vaccine messaging and uptake during epidemics. The review also highlights how trust—of institutions, of science, and between communities and health systems—remains central to a successful pandemic response. Finally, previous crises had repeatedly foreshadowed the inability of health systems to handle upcoming pandemics, yet the reactive nature of policies and practices compounded by lack of resources, infrastructure, and political will have resulted in the current failed response to COVID-19. There is therefore an urgent need for investments in implementation science and for strategies to bridge this persistent research–practice gap.