An analysis of serum samples from 31 seropositive healthcare workers (80.6% symptomatic, 19.4% asymptomatic) during SARS-CoV-2 infection shows:

• Neutralizing antibody 50% inhibitory dilution ($\text{ID}_{50}$) values correlate well with IgG and IgM optical density values against the Spike (S) protein and its receptor-binding domain (RBD), but correlate poorly with those against the nucleocapsid (N) protein.
• Asymptomatic and symptomatic healthcare workers show similar, lower $\text{ID}_{50}$ values compared to hospitalized COVID-19 patients with moderate-to-severe symptoms.
• Because of these lower neutralizing antibody titers, healthcare workers exhibit a more frequent decline in neutralizing antibody levels over time compared to more severely ill patients.