Efficacy of the recently registered inactivated Avian Influenza H5 (Re-13 & Re-14) vaccine in commercial broiler chickens compared to that of Re-5 & Re-6+Re-8 AI vaccines against the currently circulating HPAI H5N8 strain in Egypt

Abstract

Vaccination strategy against highly pathogenic Avian Influenza viruses (HPAI), with application of other measures was succeeded in limitation of the negative impact of that serious disease on the poultry industry in Egypt. The main factor determining the efficacy of an Avian Influenza vaccine is the vaccine composition matching the HPAI field strains. The prevalent HPAI field strains Nowadays in Egypt are related to the clade 2.3.4.4b, So the present study was designed to evaluate the efficacy of recently registered AI vaccine that composed of two inactivated RGAI strains which designated as Re-13 & Re- 14 and related to the clade 2.3.4.4b in commercial broiler chickens. The obtained results were compared against that of two Re-6 + Re-8 and Re-5 AI vaccines, the results proved significantly higher efficacy, HI titer and reduction in both titers and number of shedders for the Re-13 & Re-14 vaccine.