Temporal correlations between RBD-ACE2 blocking and binding antibodies to SARS-CoV-2 variants in CoronaVac-vaccinated individuals and their persistence in COVID-19 patients
Antibodies play a crucial role in protection against SARS-CoV-2. Understanding the correlation between binding and functional antibodies is essential to determine whether binding antibody levels can reliably predict neutralizing activity. We assessed antibody responses in 111 individuals vaccinated with the inactivated vaccine CoronaVac and 111 COVID-19 patients in Thailand. Plasma levels of ACE2-blocking antibodies targeting the receptor-binding domain (RBD) of SARS-Co-V2 variants were measured before vaccination and at 14 and 28 days after the second dose using a multiplex surrogate virus neutralization test. Anti-spike and anti-nucleocapsid antibodies were quantified by electrochemiluminescence immunoassay, and anti-RBD IgG by ELISA. After vaccination, blocking, anti-spike, and IgG antibody levels increased but declined rapidly within a month, whereas antibody levels in COVID-19 patients increased and persisted. Blocking and anti-spike antibody correlated at day 14 post-vaccination but not at day 28. In COVID-19 patients, correlations were moderate at day 14, and stronger at day 28. Correlations were weaker for Omicron subvariants than for the ancestral strain and non-Omicron variants. The weak correlation between blocking and anti-RBD IgG suggests binding antibodies might not predict neutralizing activity. These findings highlight the temporal nature of CoronaVac-induced immunity and the need for booster doses and variant-adapted vaccine.
Authors
- Wasun Chantratita
- Le Van Tan (ORCID: https://orcid.org/0000-0002-1791-3901)
- Viravarn Luvira (ORCID: https://orcid.org/0000-0001-9270-3720)
- Tanaya Siripoon (ORCID: https://orcid.org/0000-0003-0253-8034)
- Chee Wah Tan (ORCID: https://orcid.org/0000-0001-9837-1413)
- Phimphan Pisutsan
- Nathamon Kosoltanapiwat (ORCID: https://orcid.org/0000-0001-7465-0696)
- Narisara Chantratita (ORCID: https://orcid.org/0000-0003-3906-7379)
- Lin‐Fa Wang (ORCID: https://orcid.org/0000-0003-2752-0535)
- Wasin Matsee (ORCID: https://orcid.org/0000-0002-7165-2765)
- Rungnapa Phunpang (ORCID: https://orcid.org/0000-0001-6920-6785)
- Adul Dulsuk
- Chakkaphan Runcharoen
- Watcharapong Piyaphanee (ORCID: https://orcid.org/0000-0002-2905-1034)
- Susanna Dunachie (ORCID: https://orcid.org/0000-0001-5665-6293)
- Prapassorn Poolchanuan (ORCID: https://orcid.org/0000-0003-1668-4147)
- Wathusiri Khongsiri
- Thitiya Boonprakob
- Onura Hemtong
- Suchada Chowplijit
- Vachara Chuapaknam
Institutions
- Huachiew Chalermprakiet University (TH)
- La Jolla Institute for Immunology (US)
- Ministry of Public Health (TH)
- Siriraj Hospital (TH)
- National University of Singapore (SG)
- Mahidol University (TH)
- Angkor Hospital for Children (KH)
- Thammasat University Hospital (TH)
- University of Oxford (GB)
- Thanyarak Institute (TH)
- Duke-NUS Medical School (SG)
- Mahidol Oxford Tropical Medicine Research Unit (TH)
- Ramathibodi Hospital (TH)
- Oxford University Clinical Research Unit (VN)
- Hospital for Tropical Diseases (VN)
Publication Details
- Journal
- Scientific Reports
- Published
- 2025-05-06
- DOI
- https://doi.org/10.1038/s41598-025-98627-3
- Citations
- 1
- Primary Topic
- SARS-CoV-2 and COVID-19 Research
- Type
- article
- Field-Weighted Citation Impact
- 1.40
Funders
- Wellcome Trust
- National Institute for Health and Care Research
- Mahidol University
- National Research Council of Thailand
- Faculty of Tropical Medicine, Mahidol University