Immunogenicity of a fractional or full third dose of AZD1222 vaccine or BNT162b2 messenger RNA vaccine after two doses of CoronaVac vaccines against the Delta and Omicron variants
1
Issued Date
2023-04-01
Resource Type
ISSN
12019712
eISSN
18783511
Scopus ID
2-s2.0-85147658367
Pubmed ID
36682680
Journal Title
International Journal of Infectious Diseases
Volume
129
Start Page
19
End Page
31
Rights Holder(s)
SCOPUS
Bibliographic Citation
International Journal of Infectious Diseases Vol.129 (2023) , 19-31
Suggested Citation
Niyomnaitham S., Jongkaewwattana A., Meesing A., Pinpathomrat N., Nanthapisal S., Hirankarn N., Siwamogsatham S., Kirdlarp S., Chaiwarith R., Lawpoolsri S., Phanthanawiboon S., Thitithanyanont A., Hansasuta P., Chaiyaroj S., Pitisuttithum P. Immunogenicity of a fractional or full third dose of AZD1222 vaccine or BNT162b2 messenger RNA vaccine after two doses of CoronaVac vaccines against the Delta and Omicron variants. International Journal of Infectious Diseases Vol.129 (2023) , 19-31. 31. doi:10.1016/j.ijid.2023.01.022 Retrieved from: https://repository.li.mahidol.ac.th/handle/123456789/82095
Title
Immunogenicity of a fractional or full third dose of AZD1222 vaccine or BNT162b2 messenger RNA vaccine after two doses of CoronaVac vaccines against the Delta and Omicron variants
Author's Affiliation
Siriraj Hospital
Faculty of Tropical Medicine, Mahidol University
Faculty of Medicine, Chiang Mai University
Faculty of Medicine, Khon Kaen University
Faculty of Medicine, Prince of Songkia University
Faculty of Medicine Ramathibodi Hospital, Mahidol University
Faculty of Medicine, Thammasat University
Mahidol University
Thailand National Center for Genetic Engineering and Biotechnology
Faculty of Medicine, Chulalongkorn University
Faculty of Tropical Medicine, Mahidol University
Faculty of Medicine, Chiang Mai University
Faculty of Medicine, Khon Kaen University
Faculty of Medicine, Prince of Songkia University
Faculty of Medicine Ramathibodi Hospital, Mahidol University
Faculty of Medicine, Thammasat University
Mahidol University
Thailand National Center for Genetic Engineering and Biotechnology
Faculty of Medicine, Chulalongkorn University
Other Contributor(s)
Abstract
Objectives: The study aimed to compare the immunogenicity and safety of fractional (half) third doses of heterologous COVID-19 vaccines (AZD1222 or BNT162b2) to full doses after the two-dose CoronaVac and when boosting after three different extended intervals. Methods: At 60-<90, 90-<120, or 120-180 days intervals after the two-dose CoronaVac, participants were randomized to full-dose or half-dose AZD1222 or BNT162b2, followed up at day 28, 60, and 90. Vaccination-induced immune responses to Ancestral, Delta, and Omicron BA.1 strains were evaluated by antispike, pseudovirus, and microneutralization and T cell assays. Descriptive statistics and noninferiority cut-offs were reported as geometric mean concentration or titer and concentration or titer ratios comparing baseline to day 28 and day 90 and different intervals. Results: No safety concerns were detected. All assays and intervals showed noninferior immunogenicity between full doses and half doses. However, full-dose vaccines and/or longer 120-180-day intervals substantially improved the immunogenicity (measured by antispike or measured by pseudotyped virus neutralizing titers 50; P <0.001). Seroconversion rates were over 90% against the SARS-CoV-2 strains by all assays. Immunogenicity waned more quickly with half doses than full doses but remained high against the Ancestral or Delta strains. Against Omicron, the day 28 immunogenicity increased with longer intervals than shorter intervals for full-dose vaccines. Conclusion: Immune responses after day 28 when boosting at longer intervals after the two-dose CoronaVac was optimal. Half doses met the noninferiority criteria compared with the full dose by all the immune assays assessed.