Stakeholders have released an updated roadmap for research and development of medical countermeasures against Lassa fever. According to the roadmap authors, the virus is poised for significant advancements in therapeutics and diagnostics, with a potential vaccine on the horizon.

Lassa virus causes approximately 100,000 to 300,000 infections annually, resulting in 5,000 to 10,000 deaths, primarily in West Africa. The virus is endemic in Guinea, Liberia, Mali, Nigeria, and Sierra Leone, with other regional countries at risk. Travel-related cases have been reported globally, and climate change could expand endemic areas within Africa.

Typically spread by rodents, Lassa virus can also be transmitted through contact with the bodily fluids of an infected person. While most infections cause mild to moderate illness, the virus can be deadly, with a 1% case-fatality rate. Severe cases lead to hospitalization, and 15% of these patients die. Additionally, about 30% of those with significant illness experience hearing loss post-infection.

The roadmap emphasizes four key areas: cross-cutting issues, diagnostics, therapeutics, and vaccines.

From Neglected Virus to Promising Vaccine Candidates

Robert Garry, PhD, from Tulane University, a subject matter expert and roadmap task force member, sees the new roadmap as a milestone indicating exciting progress in diagnosing, treating, and preventing Lassa fever.

Garry notes that work on Lassa fever has progressed unevenly over the past two decades. Unlike the rapid development seen with COVID-19 countermeasures, progress for Lassa has followed a traditional pace. “When I started to work on Lassa 20 years ago, it was very neglected,” Garry told CIDRAP News. “Some vaccines are now moving into phase 2 clinical trials. We are still a few years out from having those available broadly. We are on track; it’s going to happen.”

He believes the roadmap will guide crucial research and development at a pivotal moment, potentially mitigating both the public health and economic impacts of the virus. “Because of the risk of Lassa, people don’t want to invest in or do business in this part of the world. It’s both an economic and health threat,” he said.

Reaching the Right Audience

Michael Osterholm, PhD, MPH, director of the University of Minnesota’s Center for Infectious Disease Research and Policy (CIDRAP), which publishes CIDRAP News, served as the principal investigator of the roadmap manuscript. Osterholm emphasizes the need for careful progress. “I worry about every potential factor that prevents a vaccine from becoming a vaccination,” he said, citing increased vaccine hesitancy as a significant challenge for new vaccines released post-COVID-19 pandemic.