Safety and vaccine efficacy of a glycoprotein G deficient strain of infectious laryngotracheitis virus delivered in ovo

► A candidate vaccine strain of ILTV, deficient in glycoprotein G, was given in ovo. ► Three vaccine doses were tested for safety and efficacy. ► All doses proved to be safe, with no difference in weight gain up to 3 weeks of age. ► The highest dose was the most efficacious after challenge.