We conducted a serological study to define correlates of immunity against SARS-CoV-2. Compared to those with mild coronavirus disease 2019 (COVID-19) cases, individuals with severe disease exhibited elevated virus-neutralizing titers and antibodies against the nucleocapsid (N) and the receptor binding domain (RBD) of the spike protein. Age and sex played lesser roles. All cases, including asymptomatic individuals, seroconverted by 2 weeks after PCR confirmation. Spike RBD and S2 and neutralizing antibodies remained detectable through 5–7 months after onset, whereas α-N titers diminished. Testing 5,882 members of the local community revealed only 1 sample with seroreactivity to both RBD and S2 that lacked neutralizing antibodies. This fidelity could not be achieved with either RBD or S2 alone. Thus, inclusion of multiple independent assays improved the accuracy of antibody tests in low-seroprevalence communities and revealed differences in antibody kinetics depending on the antigen. We conclude that neutralizing antibodies are stably produced for at least 5–7 months after SARS-CoV-2 infection. Display omitted •Using independent SARS-CoV-2 antigens improves the specificity of serological assays•Neutralizing and spike-specific antibody production persists for at least 5–7 months•Nucleocapsid antibodies frequently become undetectable by 5–7 months•Antibody production is higher in severe disease than in mild cases Serological assays for SARS-CoV-2 exposures are challenging due to poor positive predictive values. Ripperger et al. show that the combinatorial use of spike receptor binding domain and S2 eliminates almost all false positives. This serological assay is used to show durable antibody production for at least 5–7 months after infection.