A vaccine that could protect against two deadly diseases that kill tens of thousands of people every year, has shown encouraging trial results.
Researchers tested a vaccine designed to protect against both Lassa fever and rabies, which pose a threat in parts of Western and Sub-Saharan Africa.
Lassa fever, a viral hemorrhagic disease which is transmitted by rodents, can cause persistent vomiting, facial swelling and breathing problems – but there is currently no vaccine against the virus on the market.
The World Health Organization (WHO) has identified Lassa fever as a public health threat in western Africa, infections occur in 300,000 people every year resulting in 5,000 deaths, according to the Africa Centers for Disease Control and Prevention. But these numbers are likely an underestimate due to limited surveillance.
The disease is particularly dangerous in pregnancy with over 80 percent of late-term infections resulting in deaths to the mother or baby.
Additionally, regions where Lassa fever is common, also have a high burden of rabies, with tens of thousands of deaths annually, a disease that is almost always fatal once symptoms develop.
But a new trial showed a new dual vaccine was safe and induced immune responses against both viruses.
“This vaccine is designed to protect against two viruses of global health importance,” said stud Justin Ortiz, Professor of Medicine at University of Maryland School of Medicine’s Center for Vaccine Development and Global Health (CVD).
“By combining targets into a single product, it could reduce the need for separate vaccination efforts and streamline delivery in settings where access is limited,” he added.
For the study, published in the journal Nature Medicine, 54 healthy US adults were randomly given a different dose of the dual vaccine, while some were only given a rabies vaccine as a control.
Participants received two vaccine doses 28 days apart. Immune responses were studied for 61 days after participants received the jab.
No serious reactions were reported against the vaccine that protects against both Lassa and rabies viruses.
Results also showed the dual vaccine did induce an immune response, in comparison to the control sample for rabies only, which only induced an immune response against the rabies virus. The study is ongoing and will be studied for 394 days post-vaccination.
If the results indicate continued elevated immune responses from vaccination, researchers will continue with more advanced clinical trials.
In addition to protecting against two diseases, the new vaccine can be freeze-dried for storage, enabling distribution to areas of the world where it may be difficult to keep medical supplies cold.
“Climate change is causing Lassa fever to extend its reach far beyond its Nigerian and West African origins, putting an estimated 700 million people at risk worldwide,” said University of Maryland School of Medicine Dean Mark Gladwin.
“By 2070, the number of countries across Africa that will develop ecological conditions suitable for Lassa virus spread could drastically increase, so a vaccine to prevent this deadly infection is desperately needed.”
