Researchers Develop Single-Dose Vaccine Against Newcastle Disease and H9N2 Avian Influenza

Researchers from China Agricultural University and the Agricultural College of Yanbian University have developed and examined two recombinant turkey herpesvirus (rHVT) vaccine candidates designed to protect poultry against Newcastle disease virus (NDV) and H9N2 avian influenza. The study explores a potential single-dose vaccine strategy that could simplify current poultry vaccination programs.

The vaccines were engineered using the CRISPR-Cas9 gene editing system to express key proteins from both viruses. In laboratory tests, the modified viruses successfully produced the target proteins and remained stable after multiple cell passages. According to the researchers, this dual-expression approach could help reduce stress in poultry by combining protection against two major diseases in a single-dose vaccine.

In animal trials, rHVT-OHA-OF(H) reduced H9N2 viral shedding at 3 and 5 days post-challenge but did not protect against mortality caused by NDV. In contrast, rHVT-OHA-OF(U) provided 100% protection against NDV-related mortality and significantly reduced viral shedding for both NDV and H9N2 infections. The results suggest strong potential for a combined vaccine, although further optimization is needed before practical use.

For more information, read the abstract from Veterinary Microbiology.