In its early years, the World Health Organization led the fight to eradicate smallpox and polio. It helped governments take on the tobacco industry and championed wider access to HIV treatments. More recently, with non-profit organisations playing an expanding role, it has struggled to assert its influence and tackle new challenges, such as the rising burden of non-communicable disease. It was culpably slow to respond to the 2014 Ebola outbreak. In the absence of multilateral leadership, other actors entered the fray but co-ordination was visibly lacking.

So when officials gather in Geneva this week to select a new leader for the UN agency, they should take their vote seriously: the outcome matters deeply.

The WHO plays an essential role in convening experts to draw up advice on the prevention, diagnosis and treatment of disease. For many countries, the recommendations are the only authoritative guidance they have. The agency also has an operational role