Longitudinal kinetics of the serological response in COVID-19 recovered sufferers over a interval of 14 months
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In a current research revealed within the PLOS Pathogens journal, researchers assessed the proportion of receptor-binding area (RBD) antibodies in coronavirus illness 2019 (COVID-19)-recovered sufferers. 

Study: Longitudinal kinetics of RBD+ antibodies in COVID-19 recovered sufferers over 14 months. Image Credit: ktsdesign/Shutterstock

Accurate analysis of antibody responses in opposition to the extreme acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antigens is important to establish the historical past of viral publicity and assess viral transmission in the neighborhood. Hence, you will need to perceive the longitudinal kinetics of antibody responses after COVID-19 restoration to estimate the robustness of serological reminiscence.     

About the research

In the current research, researchers carried out a longitudinal research of alterations in RBD+ antibody ranges in COVID-19-recovered sufferers as much as 450 days after the symptom onset.

The workforce investigated the longitudinal kinetics and the persistence of SARS-CoV-2-specific antibodies by finding out a cohort of 192 people who reported restoration from COVID-19. COVID-19 analysis was based mostly on a optimistic quantitative polymerase chain response (qPCR) for SARS-CoV-2. The variety of days following symptom onset (DFS) was set as per the period reported by the members.

The research included a sub-cohort of COVID-19-recovered sufferers, together with 18 sufferers who had obtained one dose of the BNT162b2 COVID-19 messenger ribonucleic acid (mRNA) vaccine inside a period of 222 DFS. Another potential cohort included within the research comprised 17 naive people vaccinated with two doses of the BNT162b2 vaccine with a period of 21 days between the 2 doses. Samples from this group had been collected eight days after the primary dose vaccination (DFVx1) and at 4 visits performed eight, 35, 91, and 182 days after the second dose vaccination (DFVx2).

The workforce measured RBD+ immunoglobulin G (IgG), IgM, and IgA ranges by way of semi-quantitative enzyme-linked immunosorbent assay (ELISA). The ranges of antibodies at RBD+ had been categorized on the first follow-up go to (V1) to evaluate the correlation between the robustness of the antibody response post-SARS-CoV-2 an infection and the age and gender of the affected person and illness severity.

Serum samples obtained from the COVID-19 recovered sufferers had been used to estimate the robustness of the RBD+ antibodies over 14 months. The workforce explored the correlation between the time of symptom onset and RBD+ ranges of IgG, IgA, and IgM. Furthermore, the longitudinal kinetics of the antibodies was estimated by calculating the antibody titers of the RBD+ antibodies in follow-up samples obtained from recovered sufferers.                     


The research cohort had a median age of 53 years, comprising 49.2% females, with 83% reporting delicate and 17% average to extreme illness severity. After the second vaccination, the workforce collected a complete of 192 samples from COVID-19 recovered individuals in V1 and 95 samples between V2 and V4. Furthermore, 61 samples had been collected from the group comprising recovered and vaccinated individuals, whereas 68 samples had been obtained from naive vaccinees.

Assessment of the affiliation of age, gender, and illness severity with antibodies produced confirmed that the IgG and IgG ranges differed considerably between the feminine and male members. When the research cohort was labeled by sufferers aged 60 years and lesser and greater than 60 years, the IgG and IgG isotypes had been larger within the sufferers aged greater than 60 years, whereas no such variation was discovered with respect to IgM ranges. Furthermore, illness severity in the course of the energetic part of the an infection was correlated to larger IgA and IgG ranges at V1.

The workforce additionally discovered that for all of the antibody isotypes, the degrees of RBD+ decayed over the research interval of 14 months. The decay of IgG RBD+ antibody ranges had been noticed in 18.4% of the samples, IgA in 61.81%, and IgM in 54.86%. Furthermore, the generalized additive blended mannequin (GAMM) evaluation confirmed the two-phase decay profile of IgG whereas IgA and IgM had an nearly linear regression profile. Overall, the variation between the decay charges confirmed that the decay charge of IgG was considerably sooner than that of IgA.

The longitudinal kinetics of the RBD+ antibodies confirmed a major decay of the antibody ranges in all of the follow-up samples obtained from COVID-19 recovered sufferers. At V1 and V4, the variety of sufferers who had antibody titers that had been inside the threshold of the damaging management was 19.8% and 27.3% for IgG, 61.4% and 77.3% for IgA, and 50.5% and 74.2% for IgM. Furthermore, the GAMM evaluation confirmed that IgA had the quickest decay charge in comparison with IgG and IgM.    


Overall, the research findings highlighted the variations within the robustness exhibited by RBD+ antibodies amongst COVID-19-recovered sufferers and naive people. The researchers consider that the current research may also help enhance the vaccination insurance policies to fight the COVID-19 pandemic. 

Journal reference:

  • Eyran, T. et al. (2022) “Longitudinal kinetics of RBD+ antibodies in COVID-19 recovered patients over 14 months”, PLOS Pathogens, 18(6), p. e1010569. doi: 10.1371/journal.ppat.1010569. https://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1010569

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