A study published yesterday in JAMA Internal Medicine of 175 patients who recovered from mild COVID-19 reveals wide variation in the levels of antibodies against the novel coronavirus, ranging from very high levels in 2 patients to undetectable levels in 10—but no significant difference in illness duration.Researchers from Fudan University in Shanghai, China, measured antibody levels in COVID-19 patients released from Shanghai Public Health Clinical Center after being hospitalized from Jan 24 to Feb 26.Of the 175 patients, 165 (94%) had significantly higher levels of COVID-19 antibodies than 13 uninfected controls in the convalescent phase of infection.