As epidemiologists researching the social determinants of health and well-being, we study the impact of inequalities in income on physical and mental health, human development and social relationships. A very small silver lining to the coronavirus pandemic is that more people – and, crucially, more politicians and policy-makers – now understand the importance of epidemiology – i.e. the study of the distribution and determinants of health, and of public health research and practice. And, although it is the infectious disease epidemiologists and modellers who guided the government's immediate response to the onset of the pandemic, social epidemiology is critical to understanding the stark inequalities in health and well-being revealed by Covid-19 and the longer-term impacts of the responses, including lockdowns, recessions and depressions. Socio-economic and ethnic inequalities have shaped the demographics of Covid-19 and the severity of illness and mortality in different groups, a perspective also sharpened amid the pandemic by the Black Lives Matter movement. Rapidly rising rates of mental illness and of insecurities of income, employment, food and housing urgently highlight the need for routes to an inclusive recovery that could lead us to a much better new “normal”. More equal societies have weathered the storm better, benefiting from levels of trust and solidarity that have heightened resilience, whereas more unequal and authoritarian societies have suffered more illness and death. Equality really is at the heart of the matter.

Economic inequality, and its intersection with inequalities related to ethnicity, gender, disability, language, religion and more, is not just a health issue, of course. All the problems that are more common at the bottom of society, revealing a social gradient, get worse with greater inequality. In addition to shorter life expectancy, higher death rates and levels of chronic disease, increased obesity, mental illness and poor child well-being, more unequal societies suffer from more violence, including homicides, domestic violence, child maltreatment and bullying. Children and young people do less well in school and have lower chances of social mobility and higher rates of dropping out and teenage births. Drug and alcohol abuse, gambling, status consumption and consumerism also rise with inequality, while civic and cultural participation decline.