The Impact of Severe Acute Respiratory Syndrome Coronavirus 2 Vaccination and Infection on Neutralizing Antibodies: A Nation-wide Cross-sectional Analysis

Abstract

Background Neutralising antibodies (nAbs) play a critical role in the protection against severe COVID-19. In the era of vaccine boosters and repeated SARS-CoV-2 outbreaks, identifying individuals at risk represents a public health priority. Methods Relying on the Monaco COVID Public Health Programme, we evaluated nAbs from July 2021-June 2022 in 8,080 SARS-CoV-2 vaccinated and/or infected children and adults, at their inclusion visit. We stratified by infection status and investigated variables associated with nAbs using a generalised additive model. Results Infected and vaccinated participants had high and consistent nAbs (>800 IU/mL), which remained stable over time since injection, regardless of the number of vaccine doses, body mass index, sex, or age. By contrast, uninfected participants showed larger variability (two doses [V2] median 157.6; interquartile range [IQR] 43.3-439.1 IU/mL) versus three doses [V3] median 882.5; [829.5-914.8] IU/mL). In the multivariate model, nAbs decreased by 20% per month after V2 (adjusted ratio 0.80; 95%CI [0.79-0.82]), but remained stable after V3 (adjusted ratio 0.98; 95%CI [0.92-1.05]). Conclusions Hybrid immunity provided stable, high and consistent nAbs over time. The benefit of boosters was marked to restore decaying nAbs in uninfected participants. NAbs could identify individuals at risk of severe COVID-19 and provide more targeted vaccine boosters’ campaigns.

SARS-CoV-2 Antibody Dynamics after COVID-19 Vaccination and Infection: A Real-World Cross-Sectional Analysis

“…This coincides with our previous study which showed that breakthrough infection after the two-dose CoronaVac vaccination induced a higher level of Ig anti-RBD than two-dose CoronaVac vaccination alone and the third dose vaccination with AZD1222 but comparable to those achieved by the third dose BNT162b2 booster [ 16 , 17 , 18 , 19 ]. A large cohort in Monaco also showed that hybrid immunity induces high levels of neutralizing antibody against SARS-CoV-2 [ 27 ]. Another study in Denmark which compared between fully BNT162b2 vaccinated individuals with and without previous SARS-CoV-2 infection also found that the proportion of individuals with high levels of total SARS-CoV-2 antibodies was significantly higher in those with prior infection (72.2%) than in infection-naïve individuals (35.4%), indicating robust humoral response induced by hybrid immunity [ 28 ].…”

“…A third dose booster vaccination was necessary to boost the immune response and increase protection against symptomatic COVID-19 infections [ 9 , 13 , 14 , 15 ]. Recent studies that examine the dynamics of neutralizing antibody levels induced by two-dose and three-dose vaccination in infection-naïve individuals also showed that the durability of antibody improves after three-dose vaccination [ 27 ]. Besides, individuals reporting prior infection with SARS-CoV-2 exhibited significantly higher neutralizing titres compared to those without breakthrough infection [ 27 ].…”

“…Recent studies that examine the dynamics of neutralizing antibody levels induced by two-dose and three-dose vaccination in infection-naïve individuals also showed that the durability of antibody improves after three-dose vaccination [ 27 ]. Besides, individuals reporting prior infection with SARS-CoV-2 exhibited significantly higher neutralizing titres compared to those without breakthrough infection [ 27 ]. Even if more than 70–80% of Thai individuals have been infected with COVID-19 and over 80% have received two-dose vaccination (i.e., the majority of the population have hybrid immunity), reinfection still occurs as new variants continue to evolve and evade the host immunity.…”

Tracing the adaptive evolution of SARS-CoV-2 during vaccine roll-out in Norway

“…2023 ). Indeed, S:S740L, the mutation with greater differences in the vaccination probability, arose again in 2022 connected with several Omicron sub-lineages and it is estimated that S:S704L increased the growth advantage of the baseline BA.2 lineage by a 35 per cent ( Althaus et al. 2023 ).…”

Persistent humoral immune response in youth throughout the COVID-19 pandemic: prospective school-based cohort study

“…This observation was consistent across age groups. Most studies 35 – 40 found that individuals with hybrid immunity had the highest anti-spike IgG titres and neutralising responses followed by vaccinated and then infected individuals, but most of these studies focussed on adults. A study by Zaballa et al 7 , found that neutralising activity, especially for Omicron BA.1 and even more so for subsequent subvariants (Omicron BA.2, BA.2.12.1, BA.4/BA.5), was much lower in children and adolescents compared to our study despite the use of the same assay 41 .…”