It is unclear whether all people who recover from COVID-19 have antibodies that can help stave off a second infection, World Health Organizations officials said at a news conference April 13, CNBC reports.
A preliminary study of patients in China shows that some patients did not have a detectable antibody response, while others had a high antibody response, Maria Van Kerkhove, PhD, WHO's lead scientist on COVID-19 said.
And whether the patients with a high antibody response would be immune from contracting a second infection is also unknown, she said.
More data from recovered COVID-19 patients is needed before scientists can determine "what...that antibody response looks like in terms of immunity," Dr. Van Kerkhove said.
WHO officials also addressed reports of patients testing positive for the disease after recovering from COVID-19 and initially testing negative.
"There are many reasons why we might see reactivation of infection, either with the same infection or another infectious agent," said Dr. Mike Ryan, executive director of WHO's emergencies program, according to CNBC.
"There are many situations in viral infection where someone doesn't clear the virus entirely from their system," he said.