Vaccine for Lassa Fever Set To Be Trialed

There is currently no vaccine for the Lassa arenavirus, which causes Lassa fever. This hemorrhagic fever, endemic in West Africa, infects up to 300,000 people each year. Given the urgency of the situation, scientists in the Biology of Viral Emerging Infections Unit and the Viral Genomics and Vaccination Unit at the Institut Pasteur evaluated the efficacy of several vaccine candidates. Following their analyses, they identified one of these vaccines, based on the measles platform, as being the most effective to enter clinical testing in humans as soon as possible. This raises hopes in the fight against a disease that claims between 5,000 and 6,000 lives every year. Lassa fever, a hemorrhagic fever caused by the Lassa virus (LASV), is responsible for several thousands of deaths in endemic countries in West Africa every year. The natural reservoir of the virus is a peridomestic rodent that lives near or inside homes, so contacts between humans and the infected reservoir in villages are frequent (see our disease fact sheet). Humans are generally infected by ingesting or inhaling material contaminated with the animal's excreta (urine or feces). Early diagnosis of Lassa fever is difficult to establish because the first symptoms are non-specific (fever, vomiting and nausea), and there is currently no treatment. Vaccinating the populations concerned is therefore the most promising strategy to deal with recurrent outbreaks of Lassa fever. The World Health Organization (WHO) has included Lassa fever in its R&D Blueprint list of epidemic threats needing urgent R&D action. Frédéric Tangy, Head of the Institut Pasteur's Viral Genomics and Vaccination Unit, said in an interview: "When it comes to vaccines, all the easy work has already been done, and the more difficult work has still not been completed. Fundamental research is vital for the development of new solutions."