July 28 marked World Hepatitis Day. Hepatitis B and C are the two major forms of viral hepatitis, causing inflammation, damage to the liver, and sometimes cancer. Their burden is huge—more men acquired hepatitis B (890000 cases) in 2019–20 than HIV (720000 cases). In 2019 HIV caused 0.·7 million deaths, whereas hepatitis B and C combined caused 1.1 million deaths. Despite these large numbers, there is cause for optimism. The past decade has transformed viral hepatitis care. The development of direct-acting antivirals that can cure chronic hepatitis C and the rollout of hepatitis B vaccines at birth to prevent vertical transmission have ushered in a new phase in eliminating these diseases. According to this editorial in the Lancet, “Human-induced climate change has made extreme heatwaves, wildfires, and flash floods substantially more likely and more severe. Yet, health impacts are widely underestimated. Most countries have failed to adequately plan, adapt, and use evidence-based information to protect their populations. For some countries, this is a dangerous failure of action, but others lack the adequate human and financial resources to respond. So far this year, India, Pakistan, the USA, China, and Europe have experienced extreme and dangerous heatwaves that damaged vital infrastructure and threatened to overwhelm emergency service capacity. The mortality toll is staggering. According to WHO, there were at least 1700 premature and avoidable deaths in Spain and Portugal alone. For each of these deaths, many more people will have suffered serious ill health.”