What is the long‐term clinical significance of anti‐SARS‐CoV‐2‐specific IgG?

Abstract

We read with great interest the article "Clinical significance of SARS-CoV-2-specific IgG detection with a rapid antibody kit for COVID-19 patients" by Chong et al 1 The manuscript discusses the possible implications of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2)-specific Immunoglobulin G (IgG) production and the concomitant positivity in SARS-CoV-2 detection by polymerase chain reaction (PCR) in asymptomatic and symptomatic patients. This study raises some interesting questions, and we would like to humbly state a few points about the possible long-term implications of these results. SARS-CoV-2-infected patients may or may not have symptoms.Individuals that present symptoms can range from mild to severe respiratory and systemic disease, named coronavirus disease-2019Patients infected with SARS-CoV-2 can generate high titters of SARS-CoV-2-specific antibody isotypes, such as IgA, IgG, and

Immune Response to COVID-19

“…Importantly, reports have identified that asymptomatic, moderate, and severe COVID-19 present different IgM and IgG production courses and may vary in quantity. Severe COVID-19 patients produce anti-SARS-CoV-2 IgG earlier in comparison to moderate patients, and asymptomatic and mild patients produce less neutralizing antibodies in comparison to moderate and severe COVID-19 patients [52].…”

“…More importantly, serum antibody titers rapidly decay after COVID-19, with conflicting reports with antibody titers decaying after a few months post-diagnosis [53,54]. Nevertheless, antigen-specific memory B cells [55], T cells, and other components of the immunological memory remain effective and can be detected in convalescent patients [52,56]. As memory cells can rapidly respond upon subsequent antigen encounter (infection), some degree of long-term immunity is expected [57].…”

“…Nevertheless, antigen-specific memory B cells [55], T cells, and other components of the immunological memory remain effective and can be detected in convalescent patients [52,56]. As memory cells can rapidly respond upon subsequent antigen encounter (infection), some degree of long-term immunity is expected [57].…”