GENEVA -- It is unclear whether patients who have recovered from COVID-19 are immune to further infection, the World Health Organization said on Monday, as they may not develop sufficient antibodies to resist the virus the next time it enters their body. If the number of people with immunity to coronavirus is limited, it may mean a delay in lifting lockdown restrictions and social distancing guidelines.
Some members of a recent study in Shanghai showed "no detectable antibody response," while others showed a very high response, said Maria Van Kerkhove, an infectious disease expert at the WHO. If a person develops only a small number of antibodies, they may once again test positive for the virus. In South Korea, 111 people have been diagnosed as positive after recovering once.