ViTaL01: A study of a new vaccine against Lassa fever in adults aged 18-55 years
Research type
Research Study
Full title
A phase 1, first-in-human safety and immunogenicity study of a Lassa fever vaccine , ChAdOx1 LassaJ, in healthy volunteers aged 18 – 55 years in the UK.
IRAS ID
1011278
Contact name
Maheshi Ramasamy
Contact email
Sponsor organisation
University of Oxford, Research Governance, Ethics & Assurance (RGEA) Team
Research summary
Lassa fever is caused by a virus that poses a threat to a population of approximately 60 million people living in West Africa. Whilst the majority of individuals who develop it only have mild symptoms, for some it can be fatal. The virus is carried by a common rodent within West Africa which passes the disease to other rodents, their offspring and can also pass it to humans on occasion. There are no currently licensed vaccines or prophylactic treatments for protection against Lassa fever, and outbreaks are increasing in frequency with wide geographical spread. Control of outbreaks currently relies on case identification and isolation, infection prevention and control measures and supportive care for positive cases. The main purpose of the study is to assess the safety of the vaccine, as well as the immune response which develops in people who are vaccinated. We will recruit up to 31 healthy people aged 18 to 55 years. Participants will be screened for eligibility using an online questionnaire and a telephone call, followed by an in-person medical assessment. The first 6 eligible participants will have two doses of vaccine 12 weeks apart. The following 25 participants will be divided into two groups. One group (up to 20 participants) will then receive intramuscular injections of the Lassa vaccine given 12 weeks apart. The other group (5 participants) will receive two injections of saline (a placebo) given 12 weeks apart. Participants will be followed up for 1 year from the time of first vaccination. During this time they will have blood tests and medical checks performed to identify what response their immune system has made to the vaccine and to see if the vaccine could potentially provide some protection from Lassa fever in the future.
REC name
London - Riverside Research Ethics Committee
REC reference
25/LO/0404
Date of REC Opinion
31 Jul 2025
REC opinion
Further Information Favourable Opinion