The vaccine tested in this Phase 3 study is TDV. TDV co-administered with HAV vaccine will be tested to assess immunogenicity and safety in healthy participants in non-endemic area(s) for dengue and HAV.

The study will enroll approximately 900 patients. Participants will be randomly assigned to one of the three groups-which will remain undisclosed to the observer. Participants will be randomized in 1:1:1 ratio to receive:

Group 1: HAV vaccine (IM) and TDV placebo-matching injection (SC), co-administered at Day 1 (Month 0 [M0]); TDV placebo-matching injection (SC) administered at Day 90 (Month 3 [M3])

Group 2: TDV (SC) and HAV placebo-matching injection (IM), co-administered at Day 1 (Month 0 [M0]); TDV (SC) administered at Day 90(Month 3 [M3])

Group 3: TDV (SC) and HAV vaccine (IM), co-administered at Day 1 (Month 0 [M0]); TDV (SC) administered at Day 90 (Month 3 [M3])

This multi-center trial will be conducted in United Kingdom. The overall time to participate in this study is 270 days. Participants will have multiple visits to the clinic with a 6-months follow up after the last study administration, including a final visit at Day 270.