Update and narrative review of avian influenza (H5N1) infection in adult patients.

The avian influenza is a serious infection caused by influenza virus that is native to birds. Avian influenza remains a global challenge due to high transmission and mortality rates. The highly pathogenic strain of H5N1 resulted in significant outbreaks and deaths globally since the late 1800s. The most recent outbreaks in wild birds, domestic birds, and cows with some genetic variations and mutations among H5N1 strains has raised major concerns about potential transmission and public health risks. Symptoms range from asymptomatic to mild flu-like illness to severe illness that requires hospitalization. There are multiple vaccines in development for humans to protect against avian influenza, specifically the H5N1 virus. This includes a cell-based vaccine approved by the FDA for people aged 6 months and older who are at higher risk of exposure to the H5N1 virus called Audenz. Chemoprophylaxis against avian influenza following a suspected exposure should be started as soon as possible or no later than 48 h, and it is recommended to be continued for 7 days. The majority of avian influenza viruses are susceptible to neuraminidase inhibitors and cap-dependent endonuclease inhibitor. Neuraminidase inhibitors are the mainstay of the avian influenza treatment and includes oseltamivir, peramivir, and zanamivir. Baloxavir marboxil is a cap-dependent endonuclease inhibitor. This clinical review aims to highlight the background, epidemiology, clinical presentation, complications and current treatment and prevention strategies for avian influenza H5N1.