Rabies is a devastating and massively neglected disease, for which the mortality rate and burden per capita falls disproportionately upon the poorest regions of the world. Rabies is a viral disease that is largely transmitted to humans via a bite by infected animals. Once the first clinical symptoms (such as hydrophobia) have developed, the disease is uniformly lethal, and patients, if not put into an artificial coma, die in great agony. Worldwide, rabies causes approximately 59.000 deaths annually, from which the majority are young children. A vaccine exists but is associated with several drawbacks such as the need for a cold chain (kept at cool temperature), high costs, multiple dosing regimen with concomitant visits to health care facilities etc., due to which the coverage remains unacceptably low.
The yellow fever virus (YFV), a mosquito-borne flavivirus, causes severe and life-threatening infections with jaundice, systemic bleeding, shock and multi-organ failure. An estimated 900 million people living in 45 endemic countries of Africa and Latin America are at high risk of infection. Although safe and highly efficient live-attenuated prophylactic vaccines [YFV-17D, Stamaril® and YF-Vax®] are available, an estimated 200,000 cases of yellow fever still occur annually, resulting in ~30,000 deaths (www.who.int) because of inadequate supplies, the need for trained staff for administration and a cold chain.
The Japanese encephalitis virus (JEV), also a mosquito-borne flavivirus, causes viral encephalitis in many countries of Asia, with an estimated 68,000 clinical cases every year. The case-fatality rate among the patients that develop encephalitis is up to 30%, permanent neurologic or psychiatric sequelae is reported in 30-50%. As for rabies, it is primarily a children’s disease. More than 3 billion people are at risk of infection.
During the course of the RABYD-VAX project, five European research institutes combined their expertise to develop and validate a new vaccine that protects against both rabies and yellow fever/Japanese encephalitis virus. This vaccine is based on a novel proprietary vaccine technology (i.e. PLLAV, plasmid-launched live-attenuated viral vaccine platform), which has been developed by the team of the project coordinator (KU Leuven) and which has several advantages over the currently used commercial vaccines. Ultimately, this vaccine could be given as a prophylactic childhood vaccine after incorporation in the standard childhood vaccination schedule of endemic regions and this, side-by-side, with domestic and wildlife animal vaccination programs to eradicate rabies.
