RESUMEN
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.
Asunto(s)
Betacoronavirus/inmunología , Técnicas de Laboratorio Clínico/métodos , Infecciones por Coronavirus/epidemiología , Infecciones por Coronavirus/inmunología , Inmunidad Humoral , Neumonía Viral/epidemiología , Neumonía Viral/inmunología , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Anticuerpos Neutralizantes/sangre , Anticuerpos Antivirales/sangre , Arizona/epidemiología , Betacoronavirus/aislamiento & purificación , COVID-19 , Prueba de COVID-19 , Infecciones por Coronavirus/sangre , Infecciones por Coronavirus/diagnóstico , Proteínas de la Nucleocápside de Coronavirus , Femenino , Humanos , Masculino , Persona de Mediana Edad , Proteínas de la Nucleocápside/inmunología , Pandemias , Fosfoproteínas , Neumonía Viral/sangre , Neumonía Viral/diagnóstico , Prevalencia , Dominios y Motivos de Interacción de Proteínas , SARS-CoV-2 , Estudios Seroepidemiológicos , Glicoproteína de la Espiga del Coronavirus/química , Glicoproteína de la Espiga del Coronavirus/inmunología , Adulto JovenRESUMEN
We conducted an extensive serological study to quantify population-level exposure and define correlates of immunity against SARS-CoV-2. We found that relative to mild COVID-19 cases, individuals with severe disease exhibited elevated authentic virus-neutralizing titers and antibody levels against nucleocapsid (N) and the receptor binding domain (RBD) and the S2 region of spike protein. Unlike disease severity, age and sex played lesser roles in serological responses. All cases, including asymptomatic individuals, seroconverted by 2 weeks post-PCR confirmation. RBD- and S2-specific and neutralizing antibody titers remained elevated and stable for at least 2-3 months post-onset, whereas those against N were more variable with rapid declines in many samples. Testing of 5882 self-recruited members of the local community demonstrated that 1.24% of individuals showed antibody reactivity to RBD. However, 18% (13/73) of these putative seropositive samples failed to neutralize authentic SARS-CoV-2 virus. Each of the neutralizing, but only 1 of the non-neutralizing samples, also displayed potent reactivity to S2. Thus, inclusion of multiple independent assays markedly improved the accuracy of antibody tests in low seroprevalence communities and revealed differences in antibody kinetics depending on the viral antigen. In contrast to other reports, we conclude that immunity is durable for at least several months after SARS-CoV-2 infection.