title: Safety and effectiveness of a single and repeat intramuscular injection of a GnRH vaccine (GonaCon™) in adult female domestic cats.
abstract: Sterilization is a key strategy to reduce the number of domestic cats entering and killed in shelters each year. However, surgical sterilization is expensive and labour-intensive and cannot fully address the 70 million free-roaming cats estimated to exist in the United States. GonaCon™ is a gonadotropin-releasing hormone vaccine originally developed for use as a wildlife immunocontraceptive. An earlier formulation was tested in domestic cats and found to be safe and effective for long-term contraception. However, the current Environmental Protection Agency (EPA)-registered formulation consists of a different antigen-carrier protein and increased antigen concentration and has never been tested in cats. A pilot study was undertaken to evaluate the short-term safety of a single GonaCon immunization, assess the consequences of vaccinated cats receiving an accidental second GonaCon injection and determine the humoral immune response to immunization. During Phase 1, cats in Group A (n = 3) received a single intramuscular injection of GonaCon and Group B (n = 3) received a single intramuscular injection of saline. During Phase 2, Group A received a second GonaCon injection and Group B received their initial GonaCon injection. All cats developed GnRH antibodies within 30 days of vaccine administration. The endpoint titre (1:1,024,000) was similar among all cats, and levels remained high throughout the duration of the study. Four cats developed a sterile, painless, self-limiting mass at the site of injection. The mean number of days to mass development was 110.3 (range, 18-249 days). In conclusion, this preliminary study suggests that the EPA-registered GonaCon formulation is safe for continued testing in domestic cats, an accidental revaccination should not increase the risk of a vaccine reaction and the EPA-registered formulation effectively elicits a strong humoral immune response.
authors.affiliation: Center for Conservation and Research of Endangered Wildlife, Cincinnati Zoo and Botanical Garden, Cincinnati, OH, USA.
authors.forename: L M
authors.identifier: http://orcid.org/0000-0002-5951-2057
authors.initials: LM
authors.lastname: Vansandt
authors.affiliation: Department of Animal and Rangeland Sciences, Oregon State University, Corvallis, OR, USA.
authors.forename: M A
authors.initials: MA
authors.lastname: Kutzler
authors.affiliation: Department of Animal Sciences, University of Illinois, Urbana, IL, USA.
authors.forename: A E
authors.initials: AE
authors.lastname: Fischer
authors.affiliation: Institute for Human-Animal Connection, Graduate School of Social Work, University of Denver, Denver, CO, USA.
authors.forename: K N
authors.initials: KN
authors.lastname: Morris
authors.affiliation: Center for Conservation and Research of Endangered Wildlife, Cincinnati Zoo and Botanical Garden, Cincinnati, OH, USA.
authors.forename: W F
authors.initials: WF
authors.lastname: Swanson
mesh_terms: D000818:Animals; D000906:Antibodies / Q000097:blood; D002415:Cats; D003267:Contraception / Q000379:methods / Q000662:veterinary; D003269:Contraception, Immunologic / Q000009:adverse effects / Q000379:methods / Q000662:veterinary*; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000276:immunology*; D007273:Injections, Intramuscular / Q000009:adverse effects / Q000662:veterinary; D010865:Pilot Projects; D014481:United States; D014484:United States Environmental Protection Agency; D022642:Vaccines, Contraceptive / Q000008:administration & dosage / Q000009:adverse effects / Q000276:immunology
chemical_list: D000906:Antibodies; D022642:Vaccines, Contraceptive; D007987:Gonadotropin-Releasing Hormone