{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,30]],"date-time":"2026-07-30T11:11:30Z","timestamp":1785409890279,"version":"3.56.0"},"reference-count":34,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2026,6,15]],"date-time":"2026-06-15T00:00:00Z","timestamp":1781481600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/100000200","name":"United States Agency for International Development","doi-asserted-by":"crossref","award":["CA # 72038820CA00002"],"award-info":[{"award-number":["CA # 72038820CA00002"]}],"id":[{"id":"10.13039\/100000200","id-type":"DOI","asserted-by":"crossref"}]},{"award":["CA # 72038820CA00002"],"award-info":[{"award-number":["CA # 72038820CA00002"]}],"id":[{"id":"https:\/\/ror.org\/01n6e6j62","id-type":"ROR","asserted-by":"publisher"}]},{"DOI":"10.13039\/100000865","name":"Bill and Melinda Gates Foundation","doi-asserted-by":"crossref","award":["INV-034303"],"award-info":[{"award-number":["INV-034303"]}],"id":[{"id":"10.13039\/100000865","id-type":"DOI","asserted-by":"crossref"}]},{"award":["INV-034303"],"award-info":[{"award-number":["INV-034303"]}],"id":[{"id":"https:\/\/ror.org\/0456r8d26","id-type":"ROR","asserted-by":"publisher"}]},{"name":"Global Emerging Leader Award","award":["K43TW010362"],"award-info":[{"award-number":["K43TW010362"]}]},{"DOI":"10.13039\/100000002","name":"National Institutes of Health","doi-asserted-by":"crossref","award":["R01 AI130378"],"award-info":[{"award-number":["R01 AI130378"]}],"id":[{"id":"10.13039\/100000002","id-type":"DOI","asserted-by":"crossref"}]},{"DOI":"10.13039\/100000002","name":"National Institutes of Health","doi-asserted-by":"crossref","award":["D43 TW005572"],"award-info":[{"award-number":["D43 TW005572"]}],"id":[{"id":"10.13039\/100000002","id-type":"DOI","asserted-by":"crossref"}]},{"DOI":"10.13039\/501100009054","name":"icddr,b","doi-asserted-by":"crossref","id":[{"id":"10.13039\/501100009054","id-type":"DOI","asserted-by":"crossref"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Vaccines"],"abstract":"<jats:p>Background: The dynamics of humoral immune responses following primary and booster COVID-19 vaccinations are crucial to understand in order to optimize vaccination strategies. This study evaluates the magnitude and durability of SARS-CoV-2-specific IgG antibody responses across different vaccines in a large cohort of Bangladeshi adults. Methods: A total of 6300 adults from nine hospitals across eight divisions of Bangladesh were enrolled. Participants received two primary doses of either ChAdOx1 nCoV-19 (Covishield, Serum Institute of India, n = 2855), mRNA-1273 (Moderna, n = 578), BNT162b2 (Pfizer-BioNTech, n = 121), or Vero-cell-inactivated (Sinopharm, n = 2746) vaccines. Booster doses were administered at one-year intervals post-primary vaccination. SARS-CoV-2 spike receptor-binding domain (RBD)-specific IgG antibody responses were measured by ELISA using serum from vaccinees at multiple time points after two primary and two booster doses. Results: A total of 3745 individuals received booster 1 (third dose), with 59% receiving heterologous boosters (a different vaccine regimen than the primary doses). Only 5.5% (n = 347) of participants received a second booster one year after the first booster (among them, 99% received BNT162b2). Our results suggest that heterologous boosters with the mRNA vaccine induced higher IgG levels than homologous boosters for individuals who received primary vaccination with adenovirus vector-based ChAdOx1 nCoV-19 or a Vero-cell-inactivated vaccine. However, in those who initially received the mRNA-based vaccine, both homologous and heterologous boosters produced comparable IgG responses. Among all vaccine types, booster immunization with the Vero-cell-inactivated vaccine induced the lowest antibody responses. Longitudinal analysis demonstrated significantly high IgG levels over the 12 months following the first booster (p &lt; 0.0001); however, IgG levels declined significantly after the second booster dose (fourth dose). Conclusions: Heterologous boosting strategies, particularly those involving mRNA vaccines, elicit stronger and more sustained IgG responses compared to a homologous booster. However, antibody waning after the second booster highlights the need for continued monitoring and potential additional vaccine strategies.<\/jats:p>","DOI":"10.3390\/vaccines14060531","type":"journal-article","created":{"date-parts":[[2026,6,16]],"date-time":"2026-06-16T00:49:01Z","timestamp":1781570941000},"page":"531","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Longevity and Magnitude of Antibody Responses After Homologous and Heterologous COVID-19 Booster Vaccinations in Bangladesh"],"prefix":"10.3390","volume":"14","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-8316-9191","authenticated-orcid":false,"given":"Marjahan","family":"Akhtar","sequence":"first","affiliation":[{"name":"Infectious Diseases Division, International Centre for Diarrhoeal Disease Research Bangladesh (icddr,b), Dhaka 1212, Bangladesh"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Md. Rashedul","family":"Islam","sequence":"additional","affiliation":[{"name":"Infectious Diseases Division, International Centre for Diarrhoeal Disease Research Bangladesh (icddr,b), Dhaka 1212, Bangladesh"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Zahid Hasan","family":"Khan","sequence":"additional","affiliation":[{"name":"Infectious Diseases Division, International Centre for Diarrhoeal Disease Research Bangladesh (icddr,b), Dhaka 1212, Bangladesh"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Afroza","family":"Akter","sequence":"additional","affiliation":[{"name":"Infectious Diseases Division, International Centre for Diarrhoeal Disease Research Bangladesh (icddr,b), Dhaka 1212, Bangladesh"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0003-6830-6161","authenticated-orcid":false,"given":"Imam","family":"Tauheed","sequence":"additional","affiliation":[{"name":"Infectious Diseases Division, International Centre for Diarrhoeal Disease Research Bangladesh (icddr,b), Dhaka 1212, Bangladesh"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0000-6774-6104","authenticated-orcid":false,"given":"Tasnuva","family":"Ahmed","sequence":"additional","affiliation":[{"name":"Infectious Diseases Division, International Centre for Diarrhoeal Disease Research Bangladesh (icddr,b), Dhaka 1212, Bangladesh"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9415-8113","authenticated-orcid":false,"given":"Ishtiakul Islam","family":"Khan","sequence":"additional","affiliation":[{"name":"Infectious Diseases Division, International Centre for Diarrhoeal Disease Research Bangladesh (icddr,b), Dhaka 1212, Bangladesh"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mohammad Ashraful","family":"Amin","sequence":"additional","affiliation":[{"name":"Infectious Diseases Division, International Centre for Diarrhoeal Disease Research Bangladesh (icddr,b), Dhaka 1212, Bangladesh"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Fatema","family":"Khaton","sequence":"additional","affiliation":[{"name":"Infectious Diseases Division, International Centre for Diarrhoeal Disease Research Bangladesh (icddr,b), Dhaka 1212, Bangladesh"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Farhana","family":"Khanam","sequence":"additional","affiliation":[{"name":"Infectious Diseases Division, International Centre for Diarrhoeal Disease Research Bangladesh (icddr,b), Dhaka 1212, Bangladesh"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Md. Taufiqul","family":"Islam","sequence":"additional","affiliation":[{"name":"Infectious Diseases Division, International Centre for Diarrhoeal Disease Research Bangladesh (icddr,b), Dhaka 1212, Bangladesh"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Prasanta Kumar","family":"Biswas","sequence":"additional","affiliation":[{"name":"Infectious Diseases Division, International Centre for Diarrhoeal Disease Research Bangladesh (icddr,b), Dhaka 1212, Bangladesh"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Rumana","family":"Rashid","sequence":"additional","affiliation":[{"name":"Bangladesh Institute of Tropical & Infectious Diseases (BITID), Chittagong 4316, Bangladesh"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Md. Mamunur","family":"Rashid","sequence":"additional","affiliation":[{"name":"Bangladesh Institute of Tropical & Infectious Diseases (BITID), Chittagong 4316, Bangladesh"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Md. Zakir","family":"Hossain","sequence":"additional","affiliation":[{"name":"Bangladesh Institute of Tropical & Infectious Diseases (BITID), Chittagong 4316, Bangladesh"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7962-0725","authenticated-orcid":false,"given":"Ahmed Nawsher","family":"Alam","sequence":"additional","affiliation":[{"name":"Institute of Epidemiology, Disease Control and Research (IEDCR), Dhaka 1212, Bangladesh"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"A. S. M.","family":"Alamgir","sequence":"additional","affiliation":[{"name":"Institute of Epidemiology, Disease Control and Research (IEDCR), Dhaka 1212, Bangladesh"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Edward T.","family":"Ryan","sequence":"additional","affiliation":[{"name":"Division of Infectious Diseases, Massachusetts General Hospital, Boston, MA 02214, USA"},{"name":"Department of Medicine, Harvard Medical School, Boston, MA 02215, USA"},{"name":"Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA 02215, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5121-1962","authenticated-orcid":false,"given":"Sayera","family":"Banu","sequence":"additional","affiliation":[{"name":"Infectious Diseases Division, International Centre for Diarrhoeal Disease Research Bangladesh (icddr,b), Dhaka 1212, Bangladesh"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5061-3783","authenticated-orcid":false,"given":"Tahmina","family":"Shirin","sequence":"additional","affiliation":[{"name":"Institute of Epidemiology, Disease Control and Research (IEDCR), Dhaka 1212, Bangladesh"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Fahima","family":"Chowdhury","sequence":"additional","affiliation":[{"name":"Infectious Diseases Division, International Centre for Diarrhoeal Disease Research Bangladesh (icddr,b), Dhaka 1212, Bangladesh"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ashraful Islam","family":"Khan","sequence":"additional","affiliation":[{"name":"Infectious Diseases Division, International Centre for Diarrhoeal Disease Research Bangladesh (icddr,b), Dhaka 1212, Bangladesh"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3755-4763","authenticated-orcid":false,"given":"Taufiqur Rahman","family":"Bhuiyan","sequence":"additional","affiliation":[{"name":"Infectious Diseases Division, International Centre for Diarrhoeal Disease Research Bangladesh (icddr,b), Dhaka 1212, Bangladesh"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Firdausi","family":"Qadri","sequence":"additional","affiliation":[{"name":"Infectious Diseases Division, International Centre for Diarrhoeal Disease Research Bangladesh (icddr,b), Dhaka 1212, Bangladesh"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,6,15]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"211","DOI":"10.1016\/j.ijregi.2022.04.006","article-title":"Covishield vaccine induces robust immune responses in Bangladeshi adults","volume":"3","author":"Bhuiyan","year":"2022","journal-title":"IJID Reg. 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