hirty-five years ago, when I was working as a newly qualified doctor, I extracted a sausage from a woman’s windpipe. She was, in the eyes of the ambulance crew who brought her in, probably beyond saving, possibly already dead. The woman had inhaled the sausage while laughing at a joke she’d been telling her family. I leant over her, used a laryngoscope to peer into her larynx, saw the sausage and extracted it. She took a big gasp, looked around in surprise, and after a short recovery, walked out of A&E. I felt a surge of pride. I was a proper doctor. I’d saved someone’s life. My mum understood what I did for a living. After working as a clinician for many years, I became a public health researcher and worked on tuberculosis and emerging infectious diseases for about 25 years. I never got, with the same immediacy, the sense one gets from saving a life. But I suspect that through my research I’ve touched far more lives than I could ever have hoped to in clinical medicine – even if those lives remain anonymous, distant, opaque. In public health, the stakes of life and death are more distant – but no less impactful. Take, for example, Andrew Wakefield, whose fraudulent 1998 study falsely claimed a relationship between the MMR vaccine and autism. Though Wakefield was never charged with any criminal offence, his study led vaccination rates around the world and herd immunity to fall. Wakefield’s actions fractured trust in public health functions and institutions. His misconduct resulted in an incalculable number of deaths. Herein lies the difference between medicine and public health. One is proximal, the other distant. One is felt with raw emotion, the other has a slow and less measurable burn. In the frenzied debate around Dominic Cummings, many of us have focused on the hypocrisy of his actions and of Boris Johnson’s decision to keep him in post. And this hypocrisy is undoubtedly present. But hypocrisy is common in politics. There is something much more important happening here. Cummings’ actions have led to a loss of trust. Public health is about trust, a largely unwritten contract between all of us and the state. We need to trust that we each have our own and others’ interests at heart, that we share a sense of solidarity and will all do our best to protect the most vulnerable among us. We need to know that the state shares in this. Rules and regulations are insufficient to police this commitment. We need trust. Without trust, the state has few remaining tools at its disposal. It may, when struggling, draw on its coercive powers. After the Wakefield campaign, when measles outbreaks began to occur, discussion of mandating vaccination was seriously considered. In New York City, in the 1990s, because the state didn’t believe people would take their treatment for tuberculosis, patients were locked up on an island. The history of coercion and public health is long and ignominious. The esteemed medical historians Dorothy and Roy Porter once wrote that “the subtle art of the administratively possible” was at the heart of enforcing public health policies that compromise individual freedoms. Where this “art” falls short, the state may attempt to compel people through other means. Provisions are almost always made when new public health threats emerge. Coronavirus is no different. New regulations from March enabled the police to compel people to stay at home and avoid nonessential travel. The home secretary, Priti Patel, explained, “The prime minister has been clear on what we need to do: stay at home to protect our NHS and save lives … That’s why I’m giving the police these new enforcement powers, to protect the public and keep people safe.” The challenge is, as always, enforcement. The police are asked to apply common sense and discretion. When discretion seems unfair and the weight of the state bears down more heavily on some of us than others, trust is eroded. And blame begins to rise. When the burden of inconvenient and often distressing measures, such as staying at home, not visiting elderly or dying loved ones or attending the burial of family members, falls on some shoulders but not all, trust begins to fray. And, in the epidemiological parlance of the day, the reproduction number of an infection, R, begins to rise. An epidemic climbs higher and faster as observance of the rules disintegrates. Back in the 1990s I wrote a book, From Chaos to Coercion, reflecting on the challenges that arise in public health and infectious diseases when we no longer trust each other or our institutions to do the right thing. In particular, I explored the outbreak of multi-drug resistant tuberculosis in New York City. What I found most striking was that the structural causes of the terrible epidemic received little attention, and the response drew on assessments of the potential behaviour of people rather than an objective assessment of the direct threat they posed. (The city’s laws were changed to incarcerate those who were assessed as potentially posing a threat in the future.) And the institutions whose principle purpose was to care for the most vulnerable, in this case often homeless people and those with Aids, were failing completely in their task. The image of the affluent Connecticut commuter feeling threatened by a contagious disease carried by a homeless man resonated through the epidemic. Fear replaced any dormant sense of solidarity. And fear was associated inextricably with blaming individuals and institutions. Just as night follows day, blame and fear follow the loss of trust. I worry that a surge of infections and deaths will result from the public’s loss of trust in social distancing measures. And when this happens, I fear the government will slip down the slope and resort to more coercive measures. As our collective commitment to social distancing and quarantining measures wavers, we risk entering a vicious circle. Cases of Covid-19 climb, we become ever more aware of others failing to follow public health guidelines, the epidemic rages faster and chaos ensues. Epidemics are not linear. In an attempt to halt a second wave, the government would likely resort to stricter police powers and a wider imposition of existing laws. But this would be futile. Older and more vulnerable people – those dependent on our sense of solidarity – would by then have been sacrificed. The effects of Dominic Cummings’ and Boris Johnson’s actions will, to my mind, be the same as those of Wakefield. The consequences of their malign influence on trust and public health will persist for years. And the cost in human lives will likely be incalculable. • Richard Coker is emeritus professor of public health at the London School of Hygiene and Tropical Medicine