Sera Neutralizing Activities Against Severe Acute Respiratory Syndrome Coronavirus 2 and Multiple Variants 6 Months After Hospitalization for Coronavirus Disease 2019

Abstract

Background Humoral response to SARS-CoV-2 occurs within the first weeks after COVID-19. Those antibodies exert a neutralizing activity against SARS-CoV-2, whose evolution overtime after COVID-19 as well as efficiency against novel variants are however poorly characterized. Methods In this prospective study, sera of 107 patients hospitalized with COVID-19 were collected at 3- and 6-months post-infection. We performed quantitative neutralization experiments on top of high-throughput serological assays evaluating anti-Spike (S) and anti-Nucleocapsid (NP) IgG. Findings Levels of sero-neutralization and IgG rates against the ancestral strain decreased significantly over time. After 6 months, 2.8% of the patients had a negative serological status for both anti-S and anti-NP IgG. However, all sera had a persistent and effective neutralizing effect against SARS-CoV-2. IgG levels correlated with sero-neutralization and this correlation was stronger for anti-S than for anti-NP antibodies. The level of sero-neutralization quantified at 6 months correlated with markers of initial severity, notably admission in intensive care units and the need for mechanical invasive ventilation. In addition, sera collected at 6 months were tested against multiple SARS-CoV-2 variants and showed efficient neutralizing effects against D614G, B.1.1.7 and P.1 variants but a significantly weaker activity against B.1.351 variant. Interpretation Decrease of IgG rates and serological assays becoming negative did not imply loss of neutralizing capacity. Our results indicate a sustained humoral response against the ancestral strain and the D614G, B.1.1.7 and P.1 variants for at least 6 months in patients previously hospitalized for COVID-19. A weaker protection was however observed for the B.1.351 variant.

Kinetics of Neutralizing Antibodies of COVID-19 Patients Tested Using Clinical D614G, B.1.1.7, and B 1.351 Isolates in Microneutralization Assays

“…In conclusion, our results support that the strains largely circulating in 2020 provide sustained antibody-mediated protection towards the contemporary strains as well as the B.1.1.7 variant of concern rapidly spreading in e.g., Europe and the United States, but poorly against the B.1.351 variant, explaining its potential for surge in previously infected populations and highlighting the need for control measures to prevent this variant from further spread [35][36][37].…”

Antibody response after one and two jabs of the BNT162b2 vaccine in nursing home residents: The CONsort‐19 study

“… 7 This is particularly important since serum neutralising activities against SARS‐CoV‐2 six months after COVID‐19 hospitalisation remain significant for ancestral strains and for the D614G and B.1.16 variants, but are weaker for the B.1.351 variant. 40 It is therefore plausible that the post‐vaccine S‐RBD‐protein IgG level necessary to obtain protection against new variants may be higher than previously defined. 41 …”

The biological and clinical significance of emerging SARS-CoV-2 variants

“…The Alpha variant is susceptible to neutralization by most neutralizing mAbs as well as by most plasma samples from previously infected persons 97,102,121,149,159,[203][204][205][206] (fIg. 5).…”

“…The Beta variant has displayed 3-fold to 10-fold reduced susceptibility to 46% and >10-fold reduced susceptibility to 22% of convalescent plasma samples compared with early pandemic variants 97,101,104,121,124,203,204,[218][219][220] (fIg. 5).…”