In-ovo Newcastle disease virus vaccine strain TS09-C protects commercial chickens against Newcastle disease in the presence of maternally derived antibodies

Maternally derived antibodies (MDA) substantially interfere with active immunity in post-hatch vaccination, although they provide early protection against disease through passive immunity in young chickens. Previously, Newcastle disease virus (NDV) strain TS09-C was demonstrated to be safe and immunogenic as in-ovo vaccine in specific-pathogen-free chickens. Here, we evaluated the safety, protective efficacy, and duration of clinical protection...