Evidence map›Paper›PMID 40634661›Full record

ArticleScientific reports2025

Monitoring of antibodies against SARS-CoV-2 over 2 years and characterization of immune responses following Omicron infection in a South Indian community cohort.

Ramya Madhavan, Divya Gupta, Jackwin Sam Paul, Sudhir Babji, Chanduni Syed, Poornima Saravanan, Ajith Kumar, Sushil Immanuel, Vaishnavi Gandhi, Akilandeswari Eswaran and 8 more

Abstract read
In one paragraph

Article in Scientific reports, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 2 papers.

0numbers the graph read from it
0cells of the map it votes in
2citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

2 citing papers in PubMed.

  1. Article
  2. Article
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

18 authors.

Ramya MadhavanThe Wellcome Trust Research Laboratory, Christian Medical College, Vellore, India.
Divya GuptaThe Wellcome Trust Research Laboratory, Christian Medical College, Vellore, India.
Jackwin Sam PaulDepartment of Community Medicine, Christian Medical College, Bagayam, Vellore, Tamil Nadu, 632002, India.
Sudhir Babji *The Wellcome Trust Research Laboratory, Christian Medical College, Vellore, India.
Chanduni SyedThe Wellcome Trust Research Laboratory, Christian Medical College, Vellore, India.
Poornima SaravananThe Wellcome Trust Research Laboratory, Christian Medical College, Vellore, India.
Ajith KumarThe Wellcome Trust Research Laboratory, Christian Medical College, Vellore, India.
Sushil ImmanuelThe Wellcome Trust Research Laboratory, Christian Medical College, Vellore, India.
Vaishnavi GandhiThe Wellcome Trust Research Laboratory, Christian Medical College, Vellore, India.
Akilandeswari EswaranThe Wellcome Trust Research Laboratory, Christian Medical College, Vellore, India.
Pavithra DhanapalThe Wellcome Trust Research Laboratory, Christian Medical College, Vellore, India.
Lakshmi RajThe Wellcome Trust Research Laboratory, Christian Medical College, Vellore, India.
Soundari GopalThe Wellcome Trust Research Laboratory, Christian Medical College, Vellore, India.
Isai ThamizhDepartment of Community Medicine, Christian Medical College, Bagayam, Vellore, Tamil Nadu, 632002, India.
Dilesh KumarDepartment of Community Medicine, Christian Medical College, Bagayam, Vellore, Tamil Nadu, 632002, India.
Anna GeorgeThe Wellcome Trust Research Laboratory, Christian Medical College, Vellore, India.
Gagandeep KangThe Wellcome Trust Research Laboratory, Christian Medical College, Vellore, India.
Jacob JohnDepartment of Community Medicine, Christian Medical College, Bagayam, Vellore, Tamil Nadu, 632002, India. jebu@cmcvellore.ac.in.

Funding

Gates Foundation INV-024915
6 · The paper itself

Abstract

Multiple severe acute respiratory syndrome (SARS-CoV-2) exposures either due to infection or vaccination result in differential immune responses. Limited data exist on community-level SARS-CoV-2 variant exposures in India. We assessed antibody levels in 211 unvaccinated and 349 vaccinated individuals with and without prior exposure, followed for ~ 2 years (May 2021-October 2023) with baseline blood, weekly saliva for RT-PCR, and blood draws at ~ 6, 12, and 24 months. Humoral and cellular immune responses following primary (N = 8) and secondary (N = 11) Omicron infections in unvaccinated, previously exposed (N = 25), and unexposed vaccinated (N = 14) individuals were evaluated using Meso Scale Discovery and flow cytometry assays at Day 0, 30, and 90. Previously exposed individuals had higher anti-spike IgG levels at baseline (median 57,732 vs. 11,359, p < 0.001 in unvaccinated; 93,827 vs. 26,883, p < 0.001 in vaccinated) and 99% seropositivity at 2 years. Secondary Omicron infection elicited higher anti-spike IgG levels (17,320 vs. 3,930, p < 0.01) and stronger CD8 T cell responses (median CD8 AIM 0.026 vs. 0.001, p = 0.01 at Day90) than primary Omicron infection. Vaccinated individuals showed comparable CD4 and CD8 T cell responses irrespective of prior exposure, but previously exposed individuals had more durable antibodies at Day90 (p < 0.05 in previously exposed). Anti-spike IgG levels and %ACE-2 inhibition to Omicron were lower in both groups compared to other variants. High seropositivity was observed in both vaccinated and unvaccinated individuals after multiple exposures, though antibody levels were higher in individuals with prior exposure. These findings underscore preserved T cell responses to Omicron, although with lesser magnitude among unvaccinated.

Indexed as

Antibodies, ViralCOVID-19SARS-CoV-2AdolescentAdultCD8-Positive T-LymphocytesCohort StudiesCOVID-19 VaccinesFemaleHumansImmunity, CellularImmunity, HumoralImmunoglobulin GIndiaMaleMiddle AgedAntibodies, ViralCOVID-19 VaccinesImmunoglobulin GSpike Glycoprotein, Coronavirusspike protein, SARS-CoV-2Antibody kineticsAntigen imprintingCOVID-19 vaccinationOmicron variant

Identifiers

PMID40634661
PMCPMC12241409

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LicenceCC BY-NC-ND
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Registered trials

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.