Lassa vaccine trial starts in Oxford

A significant milestone has been reached in the fight against Lassa fever, a deadly virus that poses a major public‑health risk. The Oxford Vaccine Group has vaccinated the first volunteer in a first‑in‑human trial of a Lassa vaccine, marking a crucial step toward protecting vulnerable communities from the disease.

The trial, funded by the Coalition for Epidemic Preparedness Innovations (CEPI), will evaluate the safety and immune response of the ChAdOx1 Lassa vaccine in 31 participants aged 18 to 55. The vaccine uses the same viral‑vector platform as the Oxford/AstraZeneca COVID‑19 vaccine, which has been estimated to have saved millions of lives worldwide. CEPI has also supported the early preclinical development of the Lassa vaccine.

Lassa fever, caused by the Lassa virus and primarily spread by rodents, can lead to severe illness—including deafness, bleeding, and death. The disease is endemic in West Africa and has been a major public‑health concern for decades. The World Health Organization (WHO) has identified Lassa fever as a priority pathogen requiring urgent research and development because of its potential to cause large outbreaks. Experts estimate that up to 700 million people could be at risk by 2070, underscoring the need for a licensed vaccine or treatment.

Health experts have welcomed the launch of the trial as a vital step toward combating the disease. Professor Maheshi Ramasamy, chief investigator of the trial, noted that vaccines are a powerful tool in global health, saving lives and stopping outbreaks. The trial is part of a broader effort to advance the vaccine to licensure through regional leadership and coordination by the Lassa Fever Coalition.

Led by the West African Health Organization (WAHO), the Lassa Fever Coalition is working with vaccine manufacturers to accelerate development and future introduction of Lassa fever vaccines across the affected region. These coordinated efforts are seen as essential to defeating a disease that has plagued West Africa for over half a century. With the trial now underway, there is renewed hope that a vaccine against Lassa fever may soon become available, bringing relief to communities that have long lived in fear of the disease.