Many global health experts believe we should brace ourselves for more epidemics and pandemics in the future. But deadly diseases are not exactly new. Since 1948, the World Health Organization’s aim has been "the attainment by all people of the highest possible level of health". Many would say its greatest achievement has been the eradication of smallpox; in more recent years, some were critical of its response to the Covid-19 pandemic. Tulip Mazumdar, the global health correspondent for BBC News, speaks to Claire Graham about the organisation’s successes, failures and future.