Some 180,000 people with higher risks of coronavirus infection in south China's Guangdong Province have been given Covid-19 vaccine candidates as of Tuesday, the provincial government said. No serious side effects have been reported among the vaccine receivers, said the information office of the local government of Guangdong at a press briefing on Wednesday, Xinhua news agency reported. The vaccine candidates, still undergoing clinical trials, were made by the China National Biotec Group and Beijing-based Sinovac, said the office. Guangdong has started a Covid-19 vaccination campaign among groups of people with higher risks of infection. They include medical workers, customs officers, primary-level epidemic prevention workers, overseas returnees, and people working in cross-border cold-chain logistics and isolation centres.