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CDC, Fort Dodge Animal Health Achieve First Licensed DNA Vaccine

Posted on: Monday, 18 July 2005, 15:00 CDT

ATLANTA, July 18 /U.S. Newswire/ -- Scientists at the Centers for Disease Control and Prevention (CDC), in collaboration with Fort Dodge Animal Health, an animal biologics and pharmaceutical company, have developed the world's first licensed DNA vaccine. The vaccine, which protects horses from West Nile virus, was licensed by the U.S. Department of Agriculture (USDA) this week. The technology could serve as a basis for future development of human vaccines.

"This is truly an exciting innovation, and an incredible scientific breakthrough that has potential benefits far beyond preventing West Nile virus in horses," said CDC Director Dr. Julie Gerberding. "This science will allow for the development of safer and more effective human and animal vaccines more quickly."

The scientific approach used in DNA vaccines differs in a number of important ways from traditional vaccine development. Traditional vaccines, such as those used to protect people from yellow fever, polio, measles or hepatitis, involve using a disease-producing virus that has been weakened or killed. The weakened or killed virus contained in the vaccine is not able to cause the illness, but it is able to cause the body to develop immunity, or protection, against the disease. In contrast, DNA vaccines use carefully selected small pieces of the virus's genetic material that allow stimulate the vaccine recipient's body to develop protective immunity.

DNA vaccines present several advantages over traditional vaccine approaches. DNA vaccines offer a quick turnaround time during emerging epidemics-once a vaccine model is developed, it can be adapted relatively easily for similar organisms. Unlike traditional vaccines, which must be transported and stored with a small temperature range, DNA vaccines are less vulnerable to changes in temperature -- a major asset to vaccination in the developing world. In addition, DNA vaccines allow for multiple vaccine candidates to be combined in a single DNA vaccination, potentially allowing vaccination against multiple viruses at the same time. Finally, horses vaccinated with a DNA vaccine can be differentiated from those that have been naturally infected, an important factor for public health disease monitoring activities.

Work on the newly licensed horse vaccine began about five years ago as part of CDC's West Nile virus research efforts in Fort Collins, Colo. CDC scientists used DNA vaccine technology Originally developed for other mosquito-borne viruses (e.g., dengue and Japanese encephalitis) to develop an experimental vaccine. CDC and Fort Dodge Animal Health conducted clinical studies to determine the safety and effectiveness of the new vaccine. These studies showed the vaccine protected the horses from becoming ill with West Nile virus, with no adverse or major side effects. West Nile virus causes similar disease in horses and humans. Thus, the successful development of this DNA vaccine for horse should enhance the development of human vaccine.

"This new vaccine is a perfect example of how CDC works to bring science into action," said Gerberding. "Protecting people's health involves work on many fronts, including finding ways to reduce or prevent the spread of harmful viruses. We're pleased that CDC could provide scientific leadership, and we look forward to seeing additional applications of this technology in coming years."

In granting full licensure, USDA's Center for Veterinary Biologics determined that the vaccine's safety and efficacy have been satisfactorily demonstrated. Once licensed by USDA, a product of this nature can be marketed to the public. It is expected the new vaccine will be commercially available to veterinarians through Fort Dodge Animal Health in early 2006. In addition, the DNA technology used to develop the vaccine is serving as the foundation for a small human West Nile virus vaccine trial currently being conducted through the National Institutes of Health (NIH).

West Nile virus is transmitted through the bite of an infected mosquito to humans, horses, and other animals by virus-carrying mosquitoes. Introduction of West Nile virus into the United States in 1999 created major human and animal health concerns. Since 1999, there have been more than 16,000 reported cases of West Nile virus in humans and more than 650 deaths. In addition, more than 21,000 West Nile cases in horses have been reported since 1999. Currently, the only available strategies to combat WNV in humans are nationwide active surveillance, in conjunction with mosquito control efforts and individual protection with insect repellents.

CDC and Fort Dodge Animal Health established the research and development agreement in 2001 to test the vaccine and make it commercially available. Fort Dodge Animal Health is a manufacturer and distributor of prescription and over-the-counter animal health care products for the livestock, companion animal, equine, swine and poultry industries in North America and international markets.

http://www.usnewswire.com

Source: U.S. Newswire

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