Today, 7 April, is World Health Day – a day to mark the anniversary of the founding of the World Health Organization (WHO). This year’s theme is ‘building a fairer, healthier world for everyone’. It’s a call to action for equitable health care for all. And it’s an opportunity to build on the progress we’ve made in the past year in the fight against COVID-19. But how did World Health Day come about? The idea for World Health Day was first mooted at the First World Health Assembly in 1948. The Assembly – the WHO’s decision-making body – was made up of representatives from 61 countries. It was here that WHO was founded, with the aim of “attaining the highest possible level of health” for all people. At the Assembly, it was proposed that each member state should designate a World Health Day, to be celebrated on the same day each year. The day would be an opportunity to draw attention to a particular health issue of global importance. The first World Health Day was celebrated on 7 April 1950, and the theme was ‘health for all’. This was a rallying cry for universal health coverage – the idea that everyone, everywhere should have access to the health care they need, without financial hardship. Over the years, World Health Day has been used to draw attention to a wide range of health issues, from mental health to antimicrobial resistance. In recent years, the day has been an opportunity to show solidarity with health workers – the unsung heroes who save lives every day. This year, on World Health Day 2021, let’s commit to building a fairer, healthier world for everyone.