A major vaccine trial by British-Swedish drugmaker AstraZeneca was halted due to a serious adverse reaction by a participant in the trials. The company plans to have a safety review and minimise the impact on the trial timeline. Meanwhile, the World Health Organisation has started a review of the international health response strategy to the COVID-19 pandemic on Tuesday. Dr Francis Ohanyido, President of the West Africa Academy of Public Health joins CNBC Africa for more.