The inactivated trivalent avian influenza (AI) vaccine, MEFLUVAC™ H5 PLUS 8, was administered intramuscularly to hens at seven weeks of age, and the birds were challenged with highly pathogenic avian influenza virus (HPAIV) isolated in Peru (H5N1) in 2022. Birds were observed for clinical signs of disease and serum samples were analyzed for H5-specific antibodies. Virus shedding was quantified by PCR and prevalence of replicating virus was determined from tracheal and cloacal swabs. The results indicate that the vaccine is effective in preventing mortality and clinical disease and reducing viral shedding after challenge with an HPAI H5N1 isolate that shares 96.7% sequence identity with a fraction of the commercial vaccine.
Neto et al. (Sun,) studied this question.