RESUMO
Despite the availability of efficacious vaccines for animals and humans, rabies is still a major zoonosis. Prevention of rabies in dogs and cats is key for reducing the risk of transmission of this deadly disease to humans. Most veterinary vaccines are adjuvanted inactivated vaccines and have been shown to provide one to four-year duration of immunity. In response to debates about the safety of adjuvanted vaccines in cats, a non-adjuvanted feline rabies vaccine with one-year duration of immunity claim was specifically developed using the canarypoxvirus vector technology. The objective of this study was to validate a vaccination program based on primary vaccination, revaccination one year later and boosters every three years. Seronegative cats were vaccinated at 12 weeks of age and received a booster vaccination one year later. This vaccination regimen induced a strong and sustained antibody response, and all vaccinated animals were protected against virulent rabies challenge carried out 3 years after vaccination. These results validated 3-year duration of immunity after a complete basic vaccination program consisting in primary vaccination from 12 weeks of age followed by revaccination one year later with a non-adjuvanted canarypox-vectored vaccine.
Assuntos
Doenças do Gato/prevenção & controle , Vacina Antirrábica/imunologia , Vírus da Raiva/imunologia , Raiva/veterinária , Animais , Vírus da Varíola dos Canários/genética , Gatos , Vetores Genéticos , Memória Imunológica , Raiva/prevenção & controle , Vacina Antirrábica/administração & dosagem , Vacina Antirrábica/genética , Vírus da Raiva/genética , Fatores de Tempo , Vacinação/métodos , Vacinas Sintéticas/administração & dosagem , Vacinas Sintéticas/genética , Vacinas Sintéticas/imunologiaRESUMO
A classical limitation of early life immunization is the interference by maternally derived antibodies, which are known to inhibit the immune response to modified-live and killed vaccines. Several studies have convincingly shown that even minute amounts of maternally derived antibodies against equine influenza can strongly interfere with successful vaccination of foals born to immune mares. In this study we evaluated the response of foals born to vaccinated mares to immunization with a canarypox-vectored recombinant vaccine against equine influenza virus H3N8. The recombinant vaccine was able to efficiently prime foals in the presence of maternally derived immunity against influenza as was evidenced by a clear anamnestic antibody response when a secondary vaccination with the same vaccine was performed. The canarypox-vectored recombinant influenza vaccine therefore offers a unique opportunity to overcome the limitations of early life vaccination in the face of maternally derived immunity in foals.