SCMP reporter Mimi Lau speaks with fellow journalist Simone McCarthy about the call from WHO investigators for a second audit of lab facilities in and around Wuhan, just as US president Joe Biden's deadline for a report into the 'Wuhan lab leak theory' arrives; Cissy Zhou discusses the internal and global economic shockwaves from China's zero Covid strategy and the pushback from those who say China needs to live with the virus; Josephine Ma discusses new MRNA vaccine developments in mainland…