First volunteer receives Lassa fever vaccine in University of Oxford trial

The first human has been vaccinated with Oxford’s new Lassa fever vaccine in a major first‑in‑human trial

The first volunteer has received a dose of the experimental Lassa fever vaccine as part of a first‑in‑human trial at the University of Oxford, a landmark moment in the fight against a deadly virus for which no licensed vaccine currently exists. Developed by the Oxford Vaccine Group and funded by Coalition for Epidemic Preparedness Innovations (CEPI), the ChAdOx1 Lassa vaccine trial will monitor safety and immune response in 31 healthy volunteers aged 18–55. This milestone brings us a step closer to preventing outbreaks of Lassa fever, which poses a serious threat to millions in West Africa.

Lassa fever virus vaccine: A significant advancement for public health

Lassa fever is caused by the Lassa virus, which is primarily transmitted by rodents and can result in serious illness, including deafness, severe bleeding, and death. The World Health Organization has identified Lassa fever and related viruses as priority pathogens requiring urgent research and development due to their significant public health risks.

Estimates suggest that up to 700 million people could live in regions at risk of Lassa fever by 2070, and there are no current licensed vaccines or treatments for Lassa fever.

The Lassa fever vaccine was developed by researchers at the Pandemic Sciences Institute, University of Oxford, using the same viral vector as the Oxford/AstraZeneca COVID-19 vaccine.

Commenting on the launch of the trial, Professor Maheshi Ramasamy, Chief Investigator of the trial at the Oxford Vaccine Group, said: “Vaccines are one of the most powerful tools we have in global health: they save lives, stop outbreaks, and strengthen health systems, and so we’re delighted to start the VITAL01 Lassa fever vaccine study here in Oxford.

Building on Oxford’s world-leading experience in developing vaccines for emerging infections and pandemics, including COVID-19, this study is a crucial step toward protecting vulnerable communities from the devastating impact of Lassa fever.”

Dr Katrin Ramsaeur, Lassa Disease Programme Lead at CEPI, said: “Today marks a transformative milestone in the fight against the deadly Lassa fever. The launch of this Lassa vaccine clinical study has been made possible by years of rigorous and innovative science, steadfast collaboration, and an unwavering commitment to global health. While there is still important work ahead, this moment brings us closer to a future where communities no longer live in fear of this devastating disease.”

Dr Virgil Lokossou, Director of Healthcare Services at WAHO, said: “For more than half a century, Lassa fever has affected lives in West Africa – from our families and livelihoods to our hospitals and economies. Now, our region is taking bold steps to change that story. By working together with partners like the University of Oxford through the Lassa fever Coalition, we are leading the way in confronting this epidemic threat so that it no longer undermines our health and societies. Oxford’s vaccine candidate brings real promise for protection against this deadly disease, and this clinical trial arrives at a moment when regional efforts to defeat Lassa fever are stronger than ever.”