GonaCon™ is a GnRH-hemocyanin conjugate immunocontraceptive vaccine developed by the National Wildlife Research Center (NWRC), the research arm of the USDA-APHIS Wildlife Services program. It is designed to prompt an animal to create antibodies against the gonadotropin releasing hormone (GnRH) produced by the body, thus suppressing production of gonadal hormones and maturation of gametes (eggs and sperm). (To learn more about immunocontraceptive vaccines, visit our Non-surgical approaches page.)
The vaccine was developed to provide a non-lethal option for controlling wildlife populations. Indeed, it is now approved by the U.S. Environmental Protection Agency (EPA) to contracept adult female white-tailed deer and wild/feral horses and burros for a minimum of one year. Due to the mechanism of action, in addition to preventing reproduction, the vaccine has been found to suppress behaviors driven by sex hormones.
At this point, you might be wondering how a vaccine developed and approved for white-tailed deer, wild horses, and wild burros is relevant to cats and dogs. A reasonable question, indeed! When it comes to the production and effect of GnRH, mammals are quite similar, which means that the vaccine can have the same contraceptive effect on dogs and cats as it does on much larger species. It also has potential for the same contraceptive effect on males as it does on females.
Various formulations of this immunocontraceptive vaccine have been evaluated in males and females of multiple mammalian species, including cats and dogs. Study findings with one vaccine formulation indicate promise for male and, especially, female cats. Some queens remained infertile for the duration of the 5-year study, and the median period of infertility was more than 3 years. Study results prompted ACC&D to take next steps with this vaccine as a fertility control tool for cats, particularly community and feral populations. Interestingly, cats in a simulated free-roaming cat colony did not respond nearly as well to the vaccine as those in the first study. You can learn more here.
Finding a simultaneously safe and effective formulation for dogs has proven more difficult, unfortunately, as they are one of a small number of species with greater sensitivity to the vaccine adjuvant used to enhance the body’s immune response. The NWRC continues to work to develop a formulation that safely contracepts dogs, recognizing the great potential for contraceptive and rabies vaccines to be given concomitantly to free-roaming dogs and advance humane population and rabies control efforts.
Resources to learn more about GonaCon:
ACC&D GonaCon™ Product Profile and Position Paper
Contraception & Fertility Control in Dogs & Cats (ACC&D e-book)
ACC&D 5th International Symposium
ACC&D 4th International Symposium
Flagship Initiative: GonaCon Contraceptive Study