A multi-center, randomized, controlled, phase-2/3 study to evaluate the safety and immunogenicity of inactivated Japanese encephalitis vaccine in healthy ≥1 to <3 years old Indian children

Background: Japanese encephalitis (JE) is endemic in various parts of India. Due to the limited treatment options available, a new treatment option that is safe and effective is highly expected for the existing medical needs. Methods: In the present randomized Phase-2/3 study, safety, immunogenicity, and reactogenicity of JE-vaccine manufactured by Biological E (BE-JE), given in 2-dose schedule, 28-days apart was assessed in 456 healthy ≥1 to <3-year-old children compared to a licensed JE-vaccine with 3-dose schedule manufactured by Green-cross-corporation (GCC-JE). Results: The BE-JE group demonstrated non‑inferiority compared to GCC-JE group at day-56 as the lower confidence limit of the group difference was not ≥‑10%. At day-56, the geometric mean titre values were significantly higher in BE-JE group compared with the GCC‑JE group (217.97 vs 125.85; p=0.0023). No apparent difference was seen in the safety-profile between both vaccine groups, with all events reported being either mild or moderate in intensity. Also, no significant difference (p=0.2198) was reported in the number of subjects experiencing at least one adverse-event (AE) between both groups. Conclusions: The present study demonstrated BE‑JE’s Vero-cell‑based inactivated JE-vaccine, administered in 2-dose schedule to be immunogenic, well-tolerated, and non-inferior, compared to GCC‑JE-vaccine, administered in a 3‑dose schedule in the pediatric Indian-population. This study was prospectively registered with clinical trial registry of India bearing no CTRI/2011/091/000108 on 14/02/2011.