For years the WHO has aimed to streamline a complex structure, governance and financing to become more efficient. But critics say progress has been slow, especially in its emergency responses to the Ebola and Zika viruses outbreaks.

Pressure for change is building as public health specialists, non-governmental organizations and some of the WHO’s biggest donors say the organization is unwieldy, poor at coordinating responses to epidemics, and too thinly spread. Governance is also a big issue, such as the role and responsibilities of the director-general, and how the WHO operates in different regions and countries.