Beijing health authorities reported five new locally acquired Covid-19 cases on Wednesday, as the city prepares to host the Winter Olympics in just over two weeks. The new infections, identified as the Delta variant, were found in the Fangshan and Fengtai districts and bring the total cases to nine in the latest outbreak. It comes as officials in the Chinese capital have been ordered to be alert to the risk of Covid-19 spreading from inanimate objects after a controversial claim that a woman may have been infected by mail sent from Canada . Beijing has imposed tough measures as it tries to keep Covid-19 at bay during the Games, including holding the event in a “closed loop” bubble to keep athletes and other participants separate from the public. Health officials told reporters at an evening briefing that the five new cases work in cold storage and all are being treated in hospital. The first case in the outbreak was reported on Saturday and identified as the highly infectious Omicron variant, with three more infections found in compulsory mass testing early this week. Shenzhen, Beijing and Tianjin race to contain Omicron ahead of Winter Games A Beijing health official on Monday said traces of Omicron had been found on a letter sent from Toronto and could have been the source of the first case. “We do not rule out the possibility that the person was infected through contact with an object from overseas,” said Pang Xinghuo, deputy director of the Beijing Centre for Disease Control and Prevention. Although the theory has largely been dismissed by the rest of the world, Chinese officials have stepped up disinfecting mail and packages sent from abroad. In a virtual meeting on Tuesday, the city’s party chief Cai Qi ordered local officials to make sure the disease would not be spread by items sent from high-risk areas. “The conference stressed the importance of tracking and checking both [incoming] people and goods,” according to a report by the official Beijing Daily . Health Canada has said that the risk of infection from handling paper mail or cardboard packages was extremely low – a view widely shared by the international scientific community as the virus cannot survive long outside the host. However, Zhang Liubo, the chief disinfection expert at the China CDC, told state broadcaster CCTV that it was possible for international mail to carry the live virus. “An overseas object could be contaminated with a relatively large amount of virus and at the same time the delivery workers could be coughing and sneezing when handling the goods,” Zhang said. “Saliva and sputum has a lot of organic material that can offer better protection to the virus,” he said. “It is winter in the northern hemisphere and the virus may live a long time. The time for air delivery is short and there is risk when we make contact with the surface of these goods.” China has told couriers and ports to disinfect incoming goods and letters, and the CCTV report said the disinfections might explain why courier workers handling the contaminated letter had not been infected, but warned that the contents of international letters and parcels may well be contaminated with live virus. China’s zero-Covid policy: how does it work? China, while insisting on a zero-tolerance policy to Covid-19, is the only country to push the theory that chilled or frozen foods and international mail could be a transmission route. It has recently been fighting outbreaks in several cities, with both the Delta and Omicron variants appearing in Henan province. After days of mass screening and lockdowns, the outbreaks in Henan and the city of Tianjin – close to Beijing – are on a downward trend. The country reported 55 new local cases on Tuesday, compared with 127 on Monday. New local cases in Tianjin fell slightly from 18 on Monday to 14 on Tuesday. In Henan they dropped from 102 to 33 over the same period, with the city of Anyang seeing cases drop from 94 to 29. The provincial government on Wednesday announced new requirements for people planning to travel to Henan for the Lunar New Year. Anyone arriving in the province must register with the local authorities three days beforehand and show a negative test result on arrival from within the previous 48 hours, according to a government notice. People arriving in Henan from an area deemed medium- or high-risk must quarantine at a designated facility for 14 days followed by seven days of isolation at home. The central government has urged Chinese not to travel during the Lunar New Year – when millions of people usually make journeys across the country to see their families – fearing it could result in a surge of Covid-19 infections.