Safety and immunogenicity of live intranasal pertussis vaccine GamLVP in the experimental infant hamadryas baboon model

Introduction. The Gamaleya National Center of Epidemiology and Microbiology has developed a live intranasal pertussis vaccine, GamLVP, for protection against whooping cough. It is indicated for vaccination of infants and revaccination of adults of all age groups. Preclinical studies on suckling mice or rats and adult monkeys as well as clinical trials involving adult volunteers demonstrated safety and efficacy of the GamLVP vaccine. The expansion of the GamLVP vaccine to be used for vaccination of infants requires additional preclinical studies to assess its safety and immunogenicity in the most suitable experimental model of infant hamadryas baboons (Papio hamadryas).The aim of the study was to assess safety and immunogenicity of the GamLVP vaccine administered intranasally for a single dose, two-dose, and three-dose immunization of P. hamadryas infants.Materials and methods. The study was performed in three 1–2-month-old P. hamadryas infants kept, together with their mothers, in a separate cage. The results of the complete blood count and biochemical profile tests were measured before and after the immunization and experimental infection. The enzyme immunoassay (EIA) was used to detect any changes in the levels of specific IgG antibodies in sera from the mothers and infants; the agglutination test (AT) was used to measure titers of total anti-pertussis antibodies.Results. The intranasal immunization of P. hamadryas infants with the GamLVP vaccine triggered development of a specific humoral immune response mediated by IgG antibodies (pertussis toxin + filamentous hemagglutinin), increased titers of total agglutinating anti-pertussis antibodies, caused no local and systemic reactions, caused no changes in the complete blood count and biochemical profile. The experimental infection of the GamLVPimmunized P. hamadryas infants did not cause any changes in the laboratory blood test values and any clinical manifestations typical of the pertussis infection.