Safety and immunogenicity of locally produced trivalent inactivated influenza vaccine (Tri Fluvac) in healthy Thai adults aged 18–64 years in Nakhon Phanom: A Phase III double blinded, three-arm, randomized, controlled trial
Issued Date
2023-01-01
Resource Type
ISSN
0264410X
eISSN
18732518
Scopus ID
2-s2.0-85178609783
Pubmed ID
38042698
Journal Title
Vaccine
Rights Holder(s)
SCOPUS
Bibliographic Citation
Vaccine (2023)
Suggested Citation
Prasert K., Praphasiri P., Lerdsamran H., Nakphook S., Ditsungnoen D., Chawalchitiporn S., Sornwong K., Poopipatpol K., Wirachwong P., Narakorn P., Surichan S., Suthepakul N., Thangsupanimitchai N., Pittayawonganon C., Puthavathana P., Davis W.W., Mott J.A., Olsen S.J., Patumanond J. Safety and immunogenicity of locally produced trivalent inactivated influenza vaccine (Tri Fluvac) in healthy Thai adults aged 18–64 years in Nakhon Phanom: A Phase III double blinded, three-arm, randomized, controlled trial. Vaccine (2023). doi:10.1016/j.vaccine.2023.11.050 Retrieved from: https://repository.li.mahidol.ac.th/handle/20.500.14594/91449
Title
Safety and immunogenicity of locally produced trivalent inactivated influenza vaccine (Tri Fluvac) in healthy Thai adults aged 18–64 years in Nakhon Phanom: A Phase III double blinded, three-arm, randomized, controlled trial
Author's Affiliation
Kasetsart University, Chalermphrakiat Sakon Nakhon Province Campus
Faculty of Medicine, Chiang Mai University
Centers for Disease Control and Prevention
Thailand Ministry of Public Health
Thailand Government Pharmaceutical Organization
Centers for Disease Control (CDC), Thailand Field Station
Mahidol University
Nakhon Phanom Provincial Hospital
Faculty of Medicine, Chiang Mai University
Centers for Disease Control and Prevention
Thailand Ministry of Public Health
Thailand Government Pharmaceutical Organization
Centers for Disease Control (CDC), Thailand Field Station
Mahidol University
Nakhon Phanom Provincial Hospital
Other Contributor(s)
Abstract
Background: Domestic influenza vaccine production facilitates a sustainable supply for mitigating seasonal influenza and improves national health security by providing infrastructure and experience for pandemic vaccine production, if needed. Methods: A Phase III, double blind, randomized controlled trial was conducted from Sep 2019-Oct 2020 in healthy adults 18–64 years in Nakhon Phanom, Thailand. Randomization (3:3:1) compared study vaccine (Tri Fluvac), saline placebo, and an active comparator (licensed vaccine). Primary outcomes were superior efficacy compared to placebo based on RT-PCR-confirmed influenza virus infection within 12 months and non-inferiority compared to active comparator based on immunogenicity (HAI assay) at 28 days. Safety was also assessed. Results: The trial enrolled 4,284 participants (Tri Fluvac = 1,836; placebo = 1,836; active comparator = 612). There were 29 RT-PCR positive influenza infections (10 Tri Fluvac, 5.5/1,000 PY; 19 placebo, 10.4/1,000PY; 0 comparator) for an absolute protective efficacy of 46.4 (95 % CI = −22.0–76.5) compared with placebo, but the power was 43.7 %. Seroconversion difference rates between Tri Fluvac and comparator at Day 28 were 1.74 (95 % CI: −2.77, 6.25), 2.22 (−2.40, 6.84), and −0.57 (−5.41, 4.27) for A(H1N1), A(H3N2), and B strains, respectively. Adverse and severe adverse events occurred in 175 (9.5 %) Tri Fluvac, 177 (10.8 %) placebo, and 66 (10.8 %) comparator arms (p-value = 0.437, Tri Fluvac vs. comparator) Conclusions: Tri Fluvac was well tolerated, and immunogenicity was non-inferior to the active comparator, meeting U.S. Food and Drug Administration (FDA) criteria for adult vaccine licensure. Few acute respiratory infections were reported during intense COVID-19 pandemic restrictions, resulting in insufficient power to evaluate clinical efficacy.