This week the Unites Stated and the UK have had encouraging updates of their respective Covid-19 vaccine trials, showing promising results which could see a vaccine available as early next year. Back home in South Africa, we are about a month into our vaccine trial and the country is experiencing volatile surges in case numbers, will this be a threat to the progress of the vaccine trial? Joining CNBC Africa for more is Shabir Madhi, Professor of Vaccinology at the University of Witwatersrand.