NCT06745921

Safety and Immunogenicity of an Inactivated West Nile Virus Vaccine in Healthy Adults

A Phase 1 Trial to Evaluate the Safety and Immunogenicity of an Inactivated West Nile Virus Vaccine, HydroVax-001B WNV in Healthy Adults

• Status: Active Not Recruiting
• Phase: Phase 1
• Study type: Interventional
• Enrollment: 30 (actual)
• Sponsor: National Institute of Allergy and Infectious Diseases (NIAID) · NIH
• Sex: All
• Age: 18 Years – 49 Years
• Healthy volunteers: Accepted

Summary

A randomized, placebo controlled, double-blind (within dosing group), sequential dose escalation study. This phase 1 trial addresses the urgent need for a vaccine to prevent disease resulting from infection with West Nile virus (WNV), a virus that is primarily spread to people by the bite of an infected mosquito. The purpose of this Phase 1 trial is to evaluate the safety and immunogenicity of the HydroVax-001B WNV vaccine in healthy adult volunteers. The study Population will consist of healthy male and non-pregnant, non-breastfeeding female adults, 18 to 49 years of age, inclusive. Potential participants with a history of prior flavivirus infection or receipt of any flavivirus vaccine or monoclonal antibody, and those who likely had a prior flavivirus infection based on exposure history will be ineligible for the study. Participants will be randomized to receive HydroVax-001B WNV vaccine or placebo in a 12:3 ratio within a dosage group. Participants will be sequentially enrolled into two dosage groups. The primary objective is to assess the safety and reactogenicity of 4 mcg versus 10 mcg dose of the HydroVax-001B WNV vaccine administered intramuscularly (IM) on Days 1, 29 and 181.

Detailed description

A randomized, placebo controlled, double-blind (within dosing group), sequential dose escalation study. This phase 1 trial addresses the urgent need for a vaccine to prevent disease resulting from infection with West Nile virus (WNV), a virus that is primarily spread to people by the bite of an infected mosquito. The purpose of this Phase 1 trial is to evaluate the safety and immunogenicity of the HydroVax-001B WNV vaccine in healthy adult volunteers. The study Population will consist of healthy male and non-pregnant, non-breastfeeding female adults, 18 to 49 years of age, inclusive. Potential participants with a history of prior flavivirus infection or receipt of any flavivirus vaccine or monoclonal antibody, and those who likely had a prior flavivirus infection based on exposure history will be ineligible for the study. Participants will be randomized to receive HydroVax-001B WNV vaccine or placebo in a 12:3 ratio within a dosage group. Participants will be sequentially enrolled into two dosage groups. The primary objective is to assess the safety and reactogenicity of 4 mcg versus 10 mcg dose of the HydroVax-001B WNV vaccine administered intramuscularly (IM) on Days 1, 29 and 181. The secondary objective is to assess immunogenicity of 4 mcg versus 10 mcg dose of HydroVax-001B WNV vaccine given IM on Days 1, 29 and 181 as measured by WNV-specific focus reduction neutralizing test (FRNT50) after each vaccination.

Conditions

• West Nile Viral Infection

Interventions

Type	Name	Description
BIOLOGICAL	HydroVax-001B WNV	A vaccine to West Nile Virus (WNV) that is prepared by propagating naturally attenuated Kunjin strain of WNV on well characterized low-passage Vero cells. The vaccine contains 10 mcg of inactivated purified whole virion WNV formulated in a volume of 0.5 mL/dose with 0.10% aluminum hydroxide, 10% D-sorbitol, 0.001% Polysorbate 80 (Tween80) in 10 mM phosphate-buffer with 350 mM NaCl.
OTHER	Placebo	Placebo
OTHER	Sodium Chloride, 0.9%	0.9% Sodium Chloride Injection

Timeline

• Start date: 2025-02-24
• Primary completion: 2026-10-01
• Completion: 2027-11-01
• First posted: 2024-12-20
• Last updated: 2026-04-17

Locations

1 site across 1 country: United States

Regulatory

• FDA-regulated drug study