New roadmap addresses Lassa fever, a growing threat to human health

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Today stakeholders published an updated roadmap for research and development for medical countermeasures aimed at fighting Lassa fever. Roadmap authors said the virus is at a tipping point toward swift progress in terms of therapeutics and diagnostics, with a vaccine on the horizon.

Lassa virus causes about 100,000 to 300,000 infections annually, including 5,000 to 10,000 deaths, mostly in West Africa. The virus is endemic in Guinea, Liberia, Mali, Nigeria, and Sierra Leone, and other countries in the region are at risk of human Lassa fever cases and outbreaks. Travel-related cases have been reported around the world, and climate change threatens to create more endemic regions in Africa. 

The virus is typically spread by rodents, though human-to-human transmission can occur through contact with the body fluids of an infected person. Most people infected with the virus have mild to moderate illness, but with a case-fatality rate of 1%, infections can be deadly. As many as 15% of people hospitalized with severe cases die from the virus, and approximately 30% of patients with significant illness experience hearing loss after infection. 

The roadmap focuses on four main areas: cross-cutting issues, diagnostics, therapeutics, and vaccines.

From neglected virus to vaccine candidates, diagnostics 

For Robert Garry, PhD, from Tulane University a subject matter expert and a roadmap task force member, seeing the new roadmap is a sign that progress toward diagnosing, treating, and preventing Lassa fever has reached an exciting point.

Garry describes the work on Lassa in the past two decades to be both fast and slow. In contrast to the COVID-19 virus, medical countermeasures like monoclonal antibodies and vaccines have been developed at 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 in a broad way for people to get them. We are on track; it's going to happen."

Garry said the roadmap will help guide research and development at this critical juncture, where medical countermeasures could help target both the public health and economic threat 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, [but] it's an economic and a health threat," he said. 

Reaching the right audience

The progress needs to be made carefully, said Michael Osterholm, PhD, MPH, director of the University of Minnesota's Center for Infectious Disease Research and Policy (CIDRAP), which publishes CIDRAP News. Osterholm served as the principal investigator of the roadmap manuscript. 

"I worry about every potential factor that prevents a vaccine from becoming a vaccination," said Osterholm. He cited growing vaccine hesitancy as a challenge for any new vaccines released in the wake of the COVID-19 pandemic. 

I worry about every potential factor that prevents a vaccine from becoming a vaccination.

He said he hopes the roadmap reaches the right eyes. "We hope that those who read this roadmap include governments and philanthropic organizations that continue to support this work, as well as pharmaceutical companies." 

“Additionally, moving Lassa fever medical countermeasures forward by the end of the decade requires broad coalitions of dedicated basic science researchers, on-the-ground researchers, medical providers in affected areas, and input and support from affected communities in West Africa,” said Kristine Moore, MD, MPH, lead author of the roadmap. “We want to thank the many subject matter experts who provided their input into the roadmap development process and helped to identify the key gaps in progress so those issues can effectively be addressed through the goals and milestones outlined in the report.” 

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