Registered Influenza Viral Vector Based Brucella abortus Vaccine for Cattle in Kazakhstan: Age-Wise Safety and Efficacy Studies

Abstract

A novel influenza viral vector based Brucella abortus vaccine (Flu-BA) was introduced for use in cattle in Kazakhstan in 2019. In this study, the safety and efficacy of the vaccine was evaluated in male and female cattle at different ages, and during pregnancy as a part of its registration process. Our data demonstrated that the Flu-BA vaccine was safe after prime or booster vaccination in calves (5–7 months old male and female), heifers (15–17 months old) and cows (6–7 years old) and was not abortogenic in pregnant animals. A mild, localized granuloma was observed at the Flu-BA injection site. Vaccinated animals did not show signs of influenza infection or reduced milk production in dairy cows, and the influenza viral vector (IVV) was not recovered from nasal swabs or milk. Vaccinated animals in all age groups demonstrated increased IgG antibody responses against Brucella Omp16 and L7/L12 proteins with calves demonstrating the greatest increase in humoral responses. Following experimental challenge with B. abortus 544, vaccinates demonstrated greater protection and no signs of clinical disease, including abortion, were observed. The vaccine effectiveness against B. abortus 544 infection was 75, 60 and 60%, respectively, in calves, heifers and adult cows. Brucella were not isolated from calves of vaccinated cattle that were experimentally challenged during pregnancy. Our data suggests that the Flu-BA vaccine is safe and efficacious in cattle, including pregnant animals; and can therefore be administered to cattle of any age.

Brucellosis detection and the role of Brucella spp. cell wall proteins

“…They are mostly studied not for their antigenic properties but for their immunogenic and/or protective properties, both as a single immunogen [ 34 ] and along with other proteins [ 35 , 36 ]. A vector vaccine against animal brucellosis based on Omp16 and L7/L12 proteins has already been introduced into the practice of veterinary medicine in the Republic of Kazakhstan [ 37 ].…”

A review of three decades of use of the cattle brucellosis rough vaccine Brucella abortus RB51: myths and facts

“…Strikingly, after three decades of use, there is no standard operating procedure for RB51, and different vaccination methods are used without solid proof of its effectivity and safety in all physiological states and epidemiological conditions possible. Concerning the protective efficacy, the perception that RB51 is a valuable vaccine owes some credit to the misconception that “protection against abortion” is an adequate index of vaccine efficacy, an error still found in recent meta-analyses and publications [ 64 , 65 , 153 , 155 ]. Nevertheless, as forewarned many years ago [ 156 ], overlooking that some brucellosis vaccines can reduce clinical symptoms in a herd without clearing the infection is counterproductive because, if taken as an index of success, it gives a false sense of security and of progress that causes the perpetuation of the disease [ 140 ].…”