Longitudinal observation of antibody responses after SARS-CoV-2 infection at 14 months

Abstract

\n A better understanding regarding antibody responses against SARS-CoV-2 after natural infection could provide valuable insights into the future implementation of vaccination policies. In this study, we aimed to assess the dynamics of IgG antibody titers in recovered COVID-19 patients over 14 months after mild and moderately severe infection using two FDA-approved immunoassays against SARS-CoV-2 Nucleocapsid protein (NCP)and anti-spike-receptor binding domain (S-RBD) through sequential serological tests at different time points. The demographics and clinical profile, that might be associated with the magnitude and longevity of antibody response were also analyzed. \nOur results suggest antibody persistency in 31 out of 32 (96.8%) subjects at 14 months post-infection. A significant positive association was observed between disease severity and anti-S-RBD IgG titers at 14 months. Patients who reported a loss of smell and taste during the clinical course of the disease also developed significantly better antibody titers. Patients who were seronegative for anti-NCP IgG (n=7) at 10 months, were found to be seropositive for anti-S-RBD IgG at 12,13 and 14 months emphasizing on higher false-negative rate for N protein-based antibody assays when compared with the anti-S-RBD assays.\nThis study calls for prioritizing vaccination for “naive” individuals (with no previous history of COVID-19 infection) and recovered but antibody-negative individuals instead of “vaccination for all”. This strategy would be helpful in low-resource settings and areas experiencing vaccine shortages by saving time, effort, and assets that could be sourced for the vulnerable populations.