NCT06478420

COVID-19 Omicron BA.5 Subvariant Dose Finding Infection Study

A Dose Finding Human Experimental Infection Study With SARS-CoV-2 Omicron BA.5 Subvariant in Healthy Volunteers Immunologically Experienced Against SARS-CoV-2

• Status: Enrolling By Invitation
• Phase: Phase 1
• Study type: Interventional
• Enrollment: 45 (estimated)
• Sponsor: University of Oxford · Academic / Other
• Sex: All
• Age: 18 Years – 40 Years
• Healthy volunteers: Accepted

Summary

A phase 1, dose-finding open label clinical infection, safety and viral detection optimization in healthy volunteers immunologically experienced against SARS-CoV-2.

Detailed description

The aim of this phase 1 dose escalation study is to develop a safe human infection model with SARS-CoV-2 in healthy volunteers who have previously been vaccinated against SARS CoV-2 and either have been infected with SARS-CoV-2 and have evidence of this, or have developed antibodies against SARS-CoV-2. Increasing titres of SARS-CoV-2 Omicron BA.5 subvariant (starting from 1x10\^5 TCID50, up to 1x10\^8 TCID50) will be administered intranasally to different groups of 5-7 volunteers. This is in order to achieve a 50%-75% attack rate as determined by two or more quantifiable qRT-PCR detections at two consecutive timepoints from 2 days post-challenge. A Data Safety Monitoring Board (DSMB) will review safety and quantitative virology data at each dose level and will recommend continuation, dose escalation or de-escalation, based on emergent data. Dose escalation will take place in increments of up to 10 times the previous dose. Once the optimal dose of SARS-CoV-2 Omicron BA.5 subvariant has been identified in group 1, further inoculations in group 2 may proceed following DSMB review of infection rate, viral load and clinical data. Group 1 will enrol up to 28 participants whilst up to 24 participants will be enrolled into Group 2 across several sites. Rescue therapy with Paxlovid or alternative agents subject to local site availability (e.g. Remdesivir) will be administered to infected participants after any warning signs or symptoms of COVID-19 beyond mild disease. Volunteers with PCR positivity from 2 days post-challenge will remain in negative pressure isolation rooms within the clinical trials unit for a minimum of 14 days post-inoculation, and until no viable virus is found in two consecutive samples and a negative or decreasing viral load is demonstrated by qRT-PCR. Volunteers without PCR positivity from 2 days post-challenge will remain in negative pressure isolation rooms within the clinical trials unit for a minimum of 11 days post-inoculation.

Conditions

• SARS-CoV-2 Infection

Interventions

Type	Name	Description
BIOLOGICAL	Omicron BA.5 SARS-CoV-2 challenge virus	The SARS-CoV-2 challenge virus strain was originally obtained from a nose/throat swab taken from a patient who developed respiratory symptoms consistent with Covid-19. All manufacturing steps are carried out in accordance with GMP by BioMARC, operating out of Colorado State University.

Timeline

• Start date: 2024-08-08
• Primary completion: 2028-01-01
• Completion: 2028-01-01
• First posted: 2024-06-27
• Last updated: 2025-11-18

Locations

1 site across 1 country: United Kingdom