Chile used a Chinese vaccine in one of the world's fastest vaccination drives, but then saw a strange surge in Covid cases. In the UAE, some recipients had to be given a third injection after two were found to deliver insufficient immunity. Other nations have been left infuriated by supply failures. Turkey's president rebuked China's foreign minister over shortfalls that forced the closure of vaccination sites, and now cases have exploded. In Mexico, delays have forced the postponement of second doses. So are China's efforts to exploit the desperate global desire for protection, which have seen it use vaccines as a weapon to encourage nations to toe its line over Taiwan and accept technology companies such as Huawei, suddenly backfiring? This weekend, the World Health Organisation (WHO) is weighing up available data to decide whether to give emergency use listing to two key Chinese vaccines, a safety endorsement that guides regulatory agencies around the world.