The inactivated infectious bronchitis virus (IBV) vaccine used as booster in layer hens influences the breadth of protection against challenge with IBV variants

Protection of laying chickens against the Canadian DMV/1639 infectious bronchitis virus infection through priming with heterologous live vaccine and boosting with heterologous or homologous inactivated vaccine

“…While this observation is inconsistent with the previous findings of de Wit et al. ( de Wit et al., 2019 ; de Wit et al., 2022 ), it can be deduced that the combinations of vaccines employed might influence the level of VN titers against heterologous IBV strains. Following the challenge, IBV ELISA titers of the MV-C and DV-C groups showed a significant increase compared to all other groups.…”

“…While both the MV and DV groups showed a significant increase in their IBV ELISA titers, the MV group displayed a significantly higher titer compared to the DV group. It is well-established that live vaccine priming is necessary for inactivated IB vaccines to generate a potent immune response ( Box et al., 1988 ; de Wit et al., 2022 ; Ali et al., 2023 ). Thus, it is not surprising that the homologous inactivated Mass type vaccine induced a higher antibody response than the heterologous inactivated DMV/1639 type vaccine as previously reported ( Ladman et al., 2002 ).…”

“…However, adding vaccines of different serotypes to the vaccination program was shown to broaden the protection against different IBV variants ( de Wit et al., 2019 ; Hassan et al., 2022b ; Habibi et al., 2017 ). Furthermore, the additional benefit of boosting with an inactivated IB vaccine, following live priming, for protection of laying chickens was clearly demonstrated ( de Wit et al., 2019 ; de Wit et al., 2022 ; Ali et al., 2023 ). In the present study, laying hens were primed with live attenuated Mass and Conn vaccines and the efficacies of boosting the birds with either a commercial inactivated Mass type vaccine or a locally prepared autogenous inactivated DMV/1639 type vaccine were compared.…”

Pros and Cons on Use of Live Viral Vaccines in Commercial Chicken Flocks

“…Hence, controlled vaccine trials must be done for specific geographical regions/continents to determine effective IBV vaccine(s) or combinations that provide the best protection against different IBV challenges. Efficient live vaccine priming provides a beneficial contribution to this protection and confirms that inactivated IBV vaccines contribute significantly to effective protection against varying heterologous serotypes to support the protectotype concept in layers and breeders (22). Birds vaccinated with two doses of an attenuated Mass vaccine are cross protected against heterologous virus challenge (23).…”

Efficacy of a plant-produced infectious bronchitis virus-like particle vaccine in specific pathogen-free chickens

“…In this study, we produced a VLP batch and evaluated the efficacy of this plant-produced vaccine against homologous challenge with a QX-like virus. The use of a live-attenuated virus for the prime dose during vaccination improves the level of protection against IBV, while using inactivated vaccines offered broad-spectrum protection against multiple strains of IBV ( de Wit et al, 2022 ). Therefore, the plant-produced VLP was applied as a booster 3 wk after vaccination with a mix of live commercial 4-91 and Ma5 IB vaccines, as simultaneous or alternate use of Ma5 and 4/91, as commonly employed in many countries, including South Africa, induces high levels of protection against heterologous IBV types such as QX ( Cook et al, 1999 ; Terregino et al, 2008 ).…”