An Open-Label, Randomized Field Trial Demonstrates Safety and Immunogenicity of Inactivated gE-Deleted Marker Vaccine...

Area of Science:

• Veterinary Virology
• Immunology
• Animal Health

Background:

• Infectious Bovine Rhinotracheitis (IBR) is a significant disease caused by Bovine Herpesvirus-1 (BoHV-1).
• IBR is enzootic globally, with various vaccine types available for control.
• BoHV-1 infection manifests in multiple forms, including respiratory disease, reproductive issues, and neurological disorders.

Purpose of the Study:

• To evaluate the safety and immunogenicity of an indigenously developed, inactivated, glycoprotein-E (gE)-deleted marker vaccine against BoHV-1.
• To assess the protective immune response elicited by the vaccine in cattle under field conditions.

Main Methods:

• An open-label, randomized field trial was conducted on 90 healthy cattle over three months of age.
• The study assessed vaccine safety through observation of adverse events and physiological parameters.
• Immunogenicity was determined by measuring serum neutralization test (SNT50) titers post-vaccination.

Main Results:

• The inactivated BoHV-1 marker vaccine was found to be safe, with only minor, self-limiting local reactions observed.
• Vaccination induced a mild, transient increase in body temperature within physiological limits, without affecting feed intake or milk yield.
• 90% of vaccinated cattle achieved protective SNT50 titers (≥ 8) after two doses and maintained them for at least 180 days.

Conclusions:

• The indigenously developed, inactivated gE-deleted BoHV-1 marker vaccine is safe for cattle over three months of age.
• The vaccine elicits a protective immune response lasting at least six months.
• This vaccine represents a viable option for the control of Infectious Bovine Rhinotracheitis.