Ngozi Okonjo-Iweala, the first African head of the World Trade Organization, tells the FT Africa Summit that she expects global supply chain difficulties to last several months. She tells FT editor Roula Khalaf that the rhetoric about a decoupling of the US and Chinese economies is not matched by reality on the ground, and she blames a lack of global leadership for Covid-19 vaccines not ending up where they are needed most.