Longitudinal clinico-serological analysis of anti-nucleocapsid and anti-receptor binding domain of spike protein antibodies against SARS-CoV-2

A B S T R A C T Objectives: Monitoring the antibody responses to SARS-CoV-2 infection and its correlation to clini-cal spectrum of disease is critical in understanding the disease progression and protection against re-infection. We assessed the nucleocapsid (N) and receptor-binding-domain of spike (SRBD) protein specific IgG and neutralizing antibody (NAb) responses in COVID-19 patients up to 8 months and its correlation with diverse disease spectrum. Methods: During the first wave of the SARS-CoV-2 pandemic, from 284 COVID-19 patients, 608 samples were collected up to 8 months post infection. The patients were categorized as asymptomatic, symp-tomatic and severe. The N and SRBD IgG and NAb titers were evaluated and correlated with clinical data. Results: A steep increase in antigen specific antibody titers was observed till 40 days post onset of the disease (POD), followed by a partial decline till 240 days. Severe disease was associated with a stronger SRBD IgG response and higher NAb titers. The persistence of antibody response was observed in 76% against N, 80% against SRBD and 80% for NAbs of cases up to 8 months POD. Conclusion: RBD and N protein specific IgG persisted till 240 days POD which correlated with NAb re-sponse, irrespective of individual's symptomatic status indicating overall robust protection against re-infection. (c) 2021 The Authors. Published by Elsevier Ltd on behalf of International Society for Infectious Diseases. This is an open access article under the CC BY license ( http://creativecommons.org/licenses/by/4.0/ )

Automated summary

This study evaluated antibody responses to SARS-CoV-2 infection in COVID-19 patients up to 8 months post-infection, finding a steep increase in antibody titers till 40 days post onset of disease, followed by a partial decline till 240 days. Severe cases were associated with stronger antibody responses, and most cases maintained antibody responses for up to 8 months post onset of disease, indicating robust protection against re-infection.