Saint Louis University conducts research to find safe, effective vaccination for dengue

Sponsored by the National Institutes of Health (NIH), Saint Louis University's Center for Vaccine Development is conducting research of an investigational vaccine designed to prevent people from contracting dengue, a potentially lethal virus that has rapidly spread around the world.

"Finding a safe and effective vaccination for dengue is a global health priority," said Sarah George, M.D., assistant professor in the division of infectious diseases at Saint Louis University and principal investigator of the study.

"About 3.6 billion people worldwide - more than half of the world's population -- now are at risk for dengue, and it is estimated that 100 million people get sick from dengue fever every year. Annually, more than 20,000 people die worldwide from severe dengue diseases, such as dengue hemorrhagic fever and dengue shock syndrome. While dengue is most common in tropical and subtropical areas, outbreaks have occurred in the United States - specifically in Texas, Florida and Hawaii though no deaths from dengue have been reported in the United States in these outbreaks."

Saint Louis University, one of the Vaccine and Treatment Evaluation Units (VTEUs) funded by the National Institute of Allergy and Infectious Diseases (NIAID), which is part of the NIH, is the only site in the country conducting the study.

The clinical trial is the first research in humans of DENVax™, a dengue vaccine developed by Inviragen Inc., with support from NIAID, the Pediatric Dengue Vaccine Initiative and the Centers for Disease Control and Prevention (CDC). Inviragen's dengue vaccine, invented by researchers at the CDC's Division of Vector Borne Infectious Diseases, is based on a safe and weakened dengue virus that has been demonstrated to generate long-lasting anti-dengue immune responses against one of the four dengue viruses. The investigational vaccine is designed to protect people from all four closely related dengue viruses.

"Dengue has increased in incidence and spread to new countries over the past decade; a safe and easy to use dengue vaccine is sorely needed," said Jorge Osorio Ph.D., DVM, Inviragen's Chief Scientific Officer. "This Phase 1 clinical study is designed to test the safety of the vaccine in adult volunteers that have not been exposed to dengue virus."

Dengue virus is transmitted by mosquitoes (Aedes aegypti) that live in tropical and subtropical areas such as the Caribbean, Central America, South America, the Pacific Islands, Asia and Africa. These mosquitoes have also been associated with the dengue outbreaks in Texas, Florida and Hawaii.

The virus spreads to new people and new places when an Aedes aegypti mosquito bites an infected person and then transmits the virus by biting someone else. In addition to threatening people that live in endemic countries, dengue is a risk to travelers. Dengue is now more common than malaria in travelers to the Caribbean, South America and Asia.

For the clinical study (http://clinicaltrials.gov/ct2/show/NCT01110551), 72 healthy adult volunteers will receive two injections, three months apart, of a placebo or one of two strengths of investigational vaccine. The vaccination will be given either between the layers of the skin as an "intradermal" shot or just under the skin as a "subcutaneous" injection.