Dexamethasone may be part of the Covid-19 puzzle, but it's no magic bullet Right now, we could all use some good news, and it came yesterday in the form of dexamethasone. This cheap steroid could significantly reduce deaths in critically ill Covid-19 patients by one-third for those on ventilators and by one-fifth for those on oxygen alone. The drug appears to stop the damage from the severe immune reaction, called a “cytokine storm”, that researchers increasingly believe is responsible for causing some patients to have multiple organ failure and ultimately die. Had we been able to use dexamethasone from the start of the epidemic in the UK, scientists estimate up to 5,000 lives could have been saved. Off the back of these results, the NHS has announced that treatment protocols for Covid-19 patients will now include this drug, which is widely and easily available. This will also have a major impact in low- and middle-income countries as, unlike an expensive new patent drug that would be beyond their financial reach, dexamethasone costs just £5 per patient in the UK, and even less in other countries. While greeted with celebration by the UK government and the world’s press, scientists have been more cautious, given the retractions of high-profile Covid-19 papers in journals such as the Lancet over the effectiveness of hydroxychloroquine therapy. It’s important to caveat the triumph, with the fact that the scientific community has not yet seen the full paper and results. The prominent Harvard medic, Atul Gawande, best voiced these concerns in his tweet, “After all the retractions and walk backs, it is unacceptable to tout study results by press release without releasing the paper.” Putting aside these concerns, and taking the findings at face value, the trial shows that science can deliver solutions, and that by using traditional public health measures, such as social distancing and contact tracing, governments have bought themselves vital time. Since the start of the pandemic in China, there have been huge gaps in what scientists know about this virus in terms of immunity, the development of effective medicines and vaccines, and the long-term health consequences for people who recover. In this uncertainty, countries that are actively working to suppress the virus and keep numbers low have saved lives, while they build a more informed policy response. This involves learning from the scientific advances that are coming, and will continue to emerge, to help doctors manage Covid-19 patients and ensure better clinical outcomes. But we should also not think of dexamethasone as a magic bullet. This drug looks only effective in those patients already in a critical state. The real game-changer will be a drug that prevents people transitioning from mild symptoms to a severe state. With such a drug, alongside widespread testing and early detection, patients could be treated in community and outpatient clinics. It also does not address the long-term health issues associated with the virus for those with mild and severe symptoms, given that it affects so many parts of the body including the brain, lungs, heart, kidney and blood vessels. The NHS has estimated that of all the Covid-19 patients who have been hospitalised, 45% will need ongoing medical care, 4% will need inpatient rehabilitation and 1% will require long-term acute care. There are also a growing number of young and previously healthy people who, following Covid-19, struggle with recurring pain, fevers, fatigue and gastro-intestinal problems, referred to in the US as “long-haulers”. These are similar issues that have been previously identified with Sars and Mers outbreaks, two deadlier coronaviruses. Most importantly, it is not a vaccine and does not prevent the transmission of the virus within the wider population, and the attendant problems of sufficient healthcare capacity - the number of trained healthcare staff, beds, oxygen and ventilators. The world waits anxiously to hear the results of recent human trials of various vaccines that could be ready within the next year. We are also still learning about natural immunity, and whether being infected with the virus and developing antibodies has any effect for a duration of time. How long before someone can become reinfected with Sars-CoV-2? The identification of better clinical treatment of Covid-19 patients with severe symptoms should not change the core public health strategies of governments to contain and suppress this outbreak. It is another crucial piece of the puzzle in managing this pandemic, and another step forward on the long path of humanity learning to live with this virus for the months and years to come. • Prof Devi Sridhar is chair of global public health at the University of Edinburgh