Avian Influenza A(H5N1) and subtype (H7N9), commonly known as bird flu, pose significant clinical challenges. The virus can spill over from birds to mammals and humans, leading to sporadic cases of the disease.

• As of the most recent data available, there have been four confirmed human cases of avian flu in the United States since 2022. These cases were associated with exposure to dairy cows and poultry. Two of these cases resulted in fatalities.

• Globally, there have been over 200 reported cases of human infection with avian influenza A(H5N1) virus since January 2003, with over 100 fatalities.