Abstract
Background: Humoral immunity to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) may wane rapidly in persons recovered from mild coronavirus disease 2019 (COVID-19), but little is known about the longevity.
Methods: Serum samples were obtained 8, 12, and 18 months after infection from 20 patients with mild COVID-19. The binding activities of serum antibodies (immunoglobulin [Ig]A, IgG, and IgM) against SARS-CoV-2 antigens of the Wuhan-1 reference strain (wild-type) and the B.1.1.7, P.1, B.1.167.2, and B.1.1.529 variants were measured by enzyme-linked immunosorbent assays. Neutralizing antibody titers were measured using a cytopathic effect-based live virus neutralization assay.
Results: Serum IgA and IgG antibodies against spike or receptor-binding domain (RBD) protein of wild-type SARS-CoV-2 were detected for up to 18 months, and neutralizing antibodies persisted for 8 to 18 months after infection. However, any significant antibody responses against RBD proteins of SARS-CoV-2 variants were not observed, and median neutralizing antibody titers against the Delta variant at 8, 12, and 18 months were 8- to 11-fold lower than against wild-type viruses (P<.001).
Conclusions: Humoral immunity persisted for up to 18 months after SARS-CoV-2 infection in patients with mild COVID-19. However, humoral immune activity against more recently circulating variants was reduced in this population.
Keywords: COVID-19; ELISA; SARS-CoV-2; neutralizing antibodies; serological response.
【저자키워드】 COVID-19, SARS-CoV-2, Neutralizing antibodies, ELISA, serological response., 【초록키워드】 coronavirus disease, neutralizing antibody, IgG, IgM, coronavirus, Immunity, SARS-COV-2 infection, Antibody Response, variant, SARS-CoV-2 variant, Infection, delta variant, immune, Protein, IgG antibody, Immunoglobulin, Neutralization assay, B.1.1.7, RBD, IgA, enzyme-linked immunosorbent assays, P.1, Patient, Antibody titer, Mild, Neutralizing, serum antibody, B.1.1.529, SARS-CoV-2 antigen, RBD protein, Live virus, Neutralizing antibody titer, serological response, binding activity, humoral, acute respiratory syndrome, domain, wild-type SARS-CoV-2, wild-type, serum sample, cytopathic, Wuhan-1, B.1.167.2, virus, median, were measured, was reduced, circulating variant, 【제목키워드】 coronavirus 2, response, persistent, respiratory, Month,