The serological features that determine clinical outcomes in patients with COVID-19 are currently ill defined and there has been considerable controversy regarding the duration of antibody responses to SARS-CoV-2. A study in Science Immunology now reports a longitudinal investigation of plasma samples from 79 hospitalized patients with COVID-19, as well as 175 outpatients and asymptomatic SARS-CoV-2-positive individuals. Overall, outpatients and asymptomatic individuals had higher ratios of spike protein receptor-binding domain-specific IgG versus nucleoprotein-targeted IgG antibodies than hospitalized patients. In hospitalized patients, increases in antibody titres correlated with decreases in viral titres, but antibody responses during acute illness were insufficient to predict outcomes. In all patients, antibody titres started to wane around 1 month after disease onset.