Is there immunity after we got infected? Can we reinfect ourselves due to the possible existence of several covid-19 serotypes? Can we reinstate a healthcare professional to their job after 14 days of quarantine or are they at risk of re-infection and infection? / 我们感染之后会产生免疫么?我们是否会由于可 能的病毒血清的存在而再次感染? 护人员再14 天的隔离之后是否能重回岗位?这是否有再次感 染或感染别人的风险?