Protests against China's strict zero-COVID policy and restrictions on freedoms have spread to at least a dozen cities around the world in a show of solidarity with rare displays of defiance in China over the weekend. Meanwhile, a South African laboratory study using Covid-19 samples from an immunosuppressed individual over six months has shown that the virus evolved to become more pathogenic. Experts say this  means the new variant could cause more illness than the current predominant omicron strain. Sakina Kamwendo spoke to Professor Alex Sigal, from the Africa Health Research Institute