How to capture the individual and societal impacts of syndemics: the lived experience of COVID-19.

### Summary box To capture the complex interactions between health and social crises that he noticed in the HIV-AIDS pandemic, medical anthropologist Merrill Singer in the early 1990s invented the term syndemic to describe the ‘closely intertwined and mutual enhancing health problems that significantly affect the overall health status of a population’.1 Singer and Clair later expanded the notion to reconceptualise disease in a biosocial context,2 making the link to a systems approach to public health .3 Diseases, and especially highly infectious diseases that lead to pandemics, are never isolated assaults on the health of populations: they occur within a broader context characterised both by epidemiological patterns of other diseases and by social and economic factors that can dramatically affect transmission. Diseases themselves interact, creating disease clusters, and social and economic factors that affect disease dynamics are affected by them in turn. Conditions of social inequality—poverty, stigmatisation, stress and violence—play a role in disease exposure, and may dramatically increase vulnerability. Over the course of a pandemic, these same social conditions may also worsen. The value of syndemic thinking is that it ‘brings together the environment and individual embodied experience to think about what types of interventions matter—from social policy to clinical practice’.4 In 2019, Lancet commissioned a report on the global syndemic of obesity that highlighted the …