Noncommunicable diseases, climate change and iniquities: What COVID-19 has taught us about syndemic

Background COVID-19 is generating clinical challenges, lifestyle changes, economic consequences. The pandemic imposes to familiarize with concepts as prevention, vulnerability and resilience. Methods We analysed and reviewed the most relevant papers in the MEDLINE database on syndemic, noncommunicable diseases, pandemic, climate changes, pollution, resilience, vulnerability, health costs, COVID-19. Results We discuss that comprehensive strategies must face multifactorial consequences since the pandemic becomes syndemic due to interactions with noncommunicable diseases, climate changes and iniquities. The lockdown experience, on the other hand, demonstrates that it is rapidly possible to reverse epidemiologic trends and to reduce pollution. The worst outcome is evident in eight highly industrialized nations, where 12% of the world population experienced about one-third of all COVID-19-deaths worldwide. Thus, a great economic power has not been fully protective, and a change of policy is obviously needed to avoid irreversible consequences. Conclusions We are accumulating unhealthy populations living in unhealthy environments and generating unhealthy offspring. The winning policy should tackle structural inequities through a syndemic approach, to protect vulnerable populations from present and future harms.