Anti-SARS-CoV-2 Antibodies Persist for up to 13 Months and Reduce Risk of Reinfection

Abstract

Assessment of the kinetics of SARS-CoV-2 antibodies is essential to predict protection against reinfection and durability of vaccine protection. Here, we longitudinally measured Spike (S) and Nucleocapsid (N)-specific antibodies in 1,309 healthcare workers (HCW) including 393 convalescent COVID-19 and 916 COVID-19 negative HCW up to 405 days. From M1 to M7-9 after infection, SARS-CoV-2 antibodies decreased moderately in convalescent HCW in a biphasic model, with men showing a slower decay of anti-N (p=0.02), and a faster decay of anti-S (p=0.0008) than women. At M11-13, anti-N antibodies dramatically decreased (half-life: 210 days) while anti-S stabilized (half-life: 630 days) at a median of 2.41 log Arbitrary Units (AU)/mL (Interquartile Range (IQR): 2.11 -2.75). One case of reinfection was recorded in convalescent HCW (0.47 per 100 person-years) versus 50 in COVID-19 negative HCW (10.11 per 100 person-years). Correlation with live-virus neutralization assay revealed that variants D614G and B.1.1.7, but not B.1.351, were sensitive to anti-S antibodies at 2.3 log AU/mL, while IgG ≥ 3 log AU/mL neutralized all three variants. After SARS-CoV-2 vaccination, anti-S levels reached 4 logs regardless of pre-vaccination IgG levels, type of vaccine, and number of doses. Our study demonstrates a long-term persistence of anti-S IgG antibodies that may protect against reinfection. By significantly increasing cross-neutralizing antibody titers, a single-dose vaccination strengthens protection against escape mutants.

Reduced sensitivity of infectious SARS-CoV-2 variant B.1.617.2 to monoclonal antibodies and sera from convalescent and vaccinated individuals

“…3b). Therefore, our results extend previous results obtained with other variants, showing that a single dose of vaccine boosts crossneutralizing antibody responses 17,[42][43][44][45] .…”

“…Twenty seven individuals were unvaccinated, whereas 21 received a single dose of vaccine 7-81 days before sampling. As previously reported, the neutralization activity against B.1.1.7 was globally low at M12 in unvaccinated individuals 42 (Fig. 4a).…”

“…We asked whether this neutralization profile was maintained for longer periods of time. We analyzed sera from 48 individuals from another cohort of RT-qPCR-confirmed health care workers from Strasbourg University Hospitals who experienced mild disease [40][41][42] . The samples were collected at a later time point (M12), with a median of 330 days (range 144-383) POS (Table S1) 42 .…”

Reduced sensitivity of SARS-CoV-2 variant Delta to antibody neutralization

“…We asked whether this neutralization profile was maintained for longer periods of time. We analyzed sera from 47 individuals from another cohort of RT-qPCR-confirmed health care workers from Strasbourg University Hospitals who experienced mild disease 22,23 . Twenty six individuals were unvaccinated, whereas 21 received a single dose of vaccine 7-81 days before sampling.…”

“…Twenty six individuals were unvaccinated, whereas 21 received a single dose of vaccine 7-81 days before sampling. The samples were collected at a later time point (M12), with a median of 330 and 359 days for unvaccinated and vaccinated individuals, respectively (Extended Data Table 1) 23 . As observed 23 , the neutralization activity was globally low at M12 in unvaccinated individuals (Fig.…”