Maternal antibody-mediated protection against chicken astrovirus: efficacy of novel inactivated vaccine.

Chicken astrovirus (CAstV) infections cause significant economic losses in global poultry production through nephritis, enteritis, and growth retardation, yet commercial vaccines remain unavailable. This study evaluated a novel inactivated CAstV vaccine's capacity to induce protective maternal antibodies in specific-pathogen free breeder chickens and subsequent progeny protection. One hundred SPF breeder chickens received two dose vaccination (10 and 16 weeks) with inactivated vaccine containing Genogroup B strain IP2024-00664 (GenBank: PX146716.1, complete ORF-2 capsid protein gene, 2,247 bp). Comprehensive serological monitoring used validated ELISA protocols. Progeny underwent controlled challenges at 3 days post hatch with homologous IP2024-00664 and heterologous ASN/CAstV/EG/2025 (nephropathogenic Genogroup B strains) using 10 chicks per group. Endpoints included clinical protection, viral suppression, histopathological changes, and economic parameters analyzed using Cox proportional hazards models, Kaplan-Meier survival analysis, and cost effectiveness modeling. Vaccinated breeders demonstrated exceptional immunological responses with peak antibody titers of 14,350 ± 1,892 versus baseline 35 ± 8 (P < 0.001). Maternal antibody transfer ratio reached 125%. Progeny achieved complete clinical protection with 100% survival rates (20/20) against both challenges compared to control groups showing 0% survival (0/10, heterologous challenge) and 30% survival (3/10, homologous challenge) (P < 0.001). Quantitative RT-PCR confirmed functional sterilizing immunity with viral RNA levels below the assay detection limit in vaccinated groups. Cost effectiveness analysis revealed favorable return on investment (base-case ROI: 187% per protected bird; sensitivity range: 62-312%) with break even at 0.27% mortality prevention. This inactivated CAstV vaccine successfully induced high titer, transferable maternal antibodies providing functional sterilizing immunity against phylogenetically distinct nephropathogenic challenges.