NCT07455318

Boostability Assessment of Three Rabies Pre-Exposure Regimens in Healthy Volunteers 5 Years Following Priming.

A Multicentre, Open-label Trial in Healthy Volunteers to Assess the Boostability of Three Different Rabies Pre-exposure Prophylaxis Regimens When Administering a Single-dose, Intramuscular Vaccination as Simulated Post-exposure Prophylaxis at Least Five Years Following Priming.

• Status: Not Yet Recruiting
• Phase: Phase 3
• Study type: Interventional
• Enrollment: 561 (estimated)
• Sponsor: Institute of Tropical Medicine, Belgium · Academic / Other
• Sex: All
• Age: 18 Years – 60 Years
• Healthy volunteers: Not accepted

Summary

A multicentre, open label trial in healthy volunteers to assess the boostability of three different rabies pre-exposure prophylaxis regimens (2 x 1IM regimen, 2 x 2 ID regimen, 1 x 2 ID regimen) when administering a single-dose, intramuscular vaccination as simulated post-exposure prophylaxis at least five years following priming.

Detailed description

This multicentre clinical trial will include 561 participants, allocated evenly across 3 groups (187 per group). Participants are assigned to one of three groups according to their prior PrEP regimen, provided their last dose was given at least 5 years prior to enrollment. • Group 1: 21IM regimen, (N = 187): received PrEP at least 5 years ago through 1 x 1,0 mL IM injection (Day 0 and Day 7), with a 7-day interval between visits (interval of 5 to 56 days is allowed). • Group 2: 2²ID regimen (N = 187): received PrEP at least 5 years ago through 2 x 0,1 mL ID injections (Day 0 and Day 7) with a 7-day interval between visits (interval of 5 to 56 days is allowed). • Group 3: 1²ID regimen (N = 187): received PrEP at least 5 years ago through 2 x 0,1 mL ID injections on Day 0 All subjects will receive 1 x 1,0 mL IM injection of purified chick-embryo cell-culture rabies vaccine as sPEP (booster) at least five years after primary vaccination (PrEP). Neutralizing antibody titers against rabies virus will be measured using the Rapid Fluorescent Focus Inhibition Test (RFFIT) on Day 0 (before administration of sPEP) and on Days 7 and 14 after sPEP vaccination. A titre of ≥ 0.5 IU/mL is defined as adequate (WHO standard).

Conditions

• Rabies (Healthy Volunteers)

Interventions

Type	Name	Description
BIOLOGICAL	Booster vaccination	To investigate whether the boostability of a (A) two-visit IM, (B) two-visit ID and (C) one-visit ID pre-exposure vaccination regimen is non-inferior to a theoretical 99% boostability by administering a single-dose IM booster to simulate exposure to rabies at least 5 years after the pre-exposure regimens regimen.

Timeline

• Start date: 2026-05-15
• Primary completion: 2027-06-01
• Completion: 2027-06-01
• First posted: 2026-03-06
• Last updated: 2026-03-06

Locations

6 sites across 1 country: Belgium