Safety and immunogenicity of Vi-DT conjugate vaccine among 6-23-month-old children: Phase II, randomized, dose-scheduling, observer-blind Study. (October 2020)

• Record Type: Journal Article
• Authors: Capeding, Maria Rosario; Sil, Arijit; Tadesse, Birkneh Tilahun; Saluja, Tarun; Teshome, Samuel; Alberto, Edison; Kim, Deok Ryun; Park, Eun Lyeong; Park, Ju Yeon; Yang, Jae Seung; Chinaworapong, Suchada; Park, Jiwook; Jo, Sue-Kyoung; Chon, Yun; Yang, Seon-Young; Ryu, Ji Hwa; Cheong, Inho; Shim, Kyu-Young; Lee, Yoonyeong; Kim, Hun; Lynch, Julia A.; Kim, Jerome H.; Excler, Jean-Louis; Wartel, T. Anh; Sahastrabuddhe, Sushant
• Is Part Of: EClinicalMedicine. Volume 27(2020)
• Publication Date: 2020-10
• Subjects: Infants and toddlers -- Typhoid -- typhoid conjugate vaccine -- Vi-DT; Medicine -- Research -- Periodicals; Medical policy -- Periodicals; Clinical Medicine; Health Policy; Public Health; Medical policy; Medicine -- Research; Periodical; Electronic journals; Periodicals; 613
• DOI: 10.1016/j.eclinm.2020.100540
• Languages: English
• ISSNs: 2589-5370

Abstract

Abstract: Background: Typhoid causes significant mortality among young children in resource-limited settings. Conjugate typhoid vaccines could significantly reduce typhoid-related child deaths, but only one WHO-prequalified typhoid conjugate vaccine exists for young children. To address this gap, we investigated the safety, immunogenicity and dose-scheduling of Vi-DT typhoid conjugate vaccine among children aged 6-23 months. Methods: In this single center, observer blind, phase II trial, participants were randomly assigned (2:2:1) to receive one or two doses of Vi-DT or comparator vaccine. Anti-Vi IgG titer and geometric mean titers (GMT) were determined at 0, 4, 24 and 28 weeks. Data were analyzed using per-protocol and immunogenicity (a subset of intention-to-treat analysis) sets. The trial is registered with ClinicalTrials.gov (NCT03527355). Findings: Between April and July 2018, 285 children were randomized; 114 received one or two doses of Vi-DT while 57 received comparator. 277 completed the study follow-up per protocol; 112 and 110 from single- and two-dose Vi-DT schedules, respectively and 55 from the placebo group were included in the per protocol analysis. Safety profile is satisfactory. Thirteen serious adverse events were reported during the 28-week follow-up, none of which were related to Vi-DT. The seroconversion rate four weeks after the first dose was 100% (95% CI 98·3-100) in Vi-DT recipients and 7·0% (95% CI 2·8-16·7) in comparator recipients (p<0·0001). Similarly, the seroconversion rate 4 weeks after the second dose was 98·2% (95% CI 93· 6-99·5) and 21·8% (95% CI 13·0-34·4) among Vi-DT and comparator groups, respectively (p<0·0001). Anti-Vi IgG GMT was significantly higher in Vi-DT than in control group at all post-vaccination visits (p<0·0001). Interpretation: Both single and two doses of Vi-DT vaccine are safe, well tolerated, and immunogenic for infants and toddlers in a moderately endemic setting.