Longitudinal analysis of antibody dynamics in COVID-19 convalescents reveals neutralizing responses up to 16 months after infection

Abstract

Elucidating the dynamics of the neutralizing antibody (nAb) response in coronavirus disease 2019 (COVID-19) convalescents is crucial in controlling the pandemic and informing vaccination strategies. Here we measured nAb titres across 411 sequential plasma samples collected during 1-480 d after illness onset or laboratory confirmation (d.a.o.) from 214 COVID-19 convalescents, covering the clinical spectrum of disease and without additional exposure history after recovery or vaccination against SARS-CoV-2, using authentic SARS-CoV-2 microneutralization (MN) assays. Forty-eight samples were also tested for neutralizing activities against the circulating variants using pseudotyped neutralization assay. Results showed that anti-RBD IgG and MN titres peaked at ~120 d.a.o. and subsequently declined, with significantly reduced nAb responses found in 91.67% of COVID-19 convalescents (≥50% decrease in current MN titres compared with the paired peak MN titres). Despite this decline, majority of the COVID-19 convalescents maintained detectable anti-RBD IgG and MN titres at 400-480 d.a.o., with undetectable neutralizing activity found in 14.41% (16/111) of the mild and 50% (5/10) of the asymptomatic infections at 330-480 d.a.o. Persistent antibody-dependent immunity could provide protection against circulating variants after one year, despite significantly decreased neutralizing activities against Beta, Delta and Mu variants. In conclusion, these data show that despite a marked decline in neutralizing activity over time, nAb responses persist for up to 480 d in most convalescents of symptomatic COVID-19, whereas a high rate of undetectable nAb responses was found in convalescents from asymptomatic infections.

Long-term T cell perturbations and waning antibody levels in individuals needing hospitalization for COVID-19

“…In addition, the level of lactate dehydrogenase (LDH) was much higher in most patients than in the healthy controls with median of 6.9 µKat/L ( Table 1 and Figure 2A ). Both these findings are consistent with observations made by others [45, 46]. No association was found between disease severity and biological sex, age, or clinical characteristics (data not shown).…”

Equipment-free, gold nanoparticle based semiquantitative assay of SARS-CoV-2-S1RBD IgG from fingertip blood: A practical strategy for on-site measurement of COVID-19 antibodies

“…5 , R 2 = 0.828 for mRNA, 0.795 for inactivated group). This observation agreed with previous reports using venous blood samples measured by standard plaque reduction neutralization test (PRNT) in large population [ 5 , [19] , [20] , [21] ]. This agreement supported that our machine-free, semi-quantitative assay could provide reliable quantitation data for serum antibodies.…”

Twelve-Month Longitudinal Serology in SARS-CoV-2 Naïve and Experienced Vaccine Recipients and Unvaccinated COVID-19-Infected Individuals

“…Serum spike-specific IgG and neutralizing antibodies against SARS-CoV-2 have been reported as correlates of protection [ 3 , 4 ]. SARS-CoV-2-specific IgG persists but wanes following SARS-CoV-2 infection and the primary vaccine series prior to an additional dose [ 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 ]. Past studies have compared spike-specific IgG levels post-vaccination between individuals who experienced a SARS-CoV-2 infection before vaccination and naïve individuals, mainly at early time points [ 12 , 13 , 14 , 15 , 16 ].…”