Valneva SE

About Phase 2 Trial VLA1553-221

VLA1553-221 was a multi-center, randomized, observer-blinded, dose response Phase 2 clinical trial in 304 healthy children aged one to eleven years. The trial was performed at three trial sites in the Dominican Republic and Honduras. The primary and secondary objectives of the trial were to evaluate the safety and immunogenicity of two different dose levels of Valneva’s single-shot chikungunya vaccine. Participants were randomized 2:2:1 to receive

9 https://bluedot.global/vaccines-on-the-table-as-chikungunya-outbreak-intensifies-in-india/

10 https://www.cdc.gov/chikungunya/data-maps/index.html

11 https://jvi.asm.org/content/jvi/88/20/11644.full.pdf

12 https://cmr.asm.org/content/31/1/e00104-16

13 PAHO/WHO data: Number of reported cases of chikungunya fever in the Americas (Cumulative Cases 2018-2023 and Cases per year 2013-2017). https://www.paho.org/data/index.php/en/mnu-topics/chikv-en/550-chikv-weekly-en.html. Last accessed 01 Aug 2023.

14 Geographical expansion of cases of dengue and chikungunya beyond the historical areas of transmission in the Region of the Americas (who.int)

either a full dose (licensed IXCHIQ® formulation and presentation) or a half dose of the vaccine, or an active control (Nimenrix). Additional information, including a detailed description of the trial design, eligibility criteria and investigator sites, is available at ClinicalTrials.gov (Identifier: NCT06106581).