Researchers at the Centers for Disease and Prevention (CDC) recently reviewed details of people infected with H5N1 avian influenza virus (Garg S, Reinhart K, Couture A, et al. Highly Pathogenic Avian Influenza A (H5N1) Virus Infections in Humans. New Engl J Med. 2025 Feb 27;392(9):843-854). The authors analyzed data from 46 patients, 20 of whom were exposed to poultry, 25 of whom were exposed to infected dairy cows, and one of whom had no identified exposure.
Among the 45 patients with animal exposures, most had mild illness, none were hospitalized, and none died. A total of 42 patients (93%) had conjunctivitis, 22 (49%) had fever, and 16 (36%) had respiratory symptoms. The median duration of illness was about four days. Most patients (87%) received the antiviral drug oseltamivir. These viruses remain susceptible to the drug. There was no evidence of human-to-human spread of the virus.
The authors concluded that “In the cases identified to date, A(H5N1) viruses generally caused mild illness, mostly conjunctivitis, of short duration, predominantly in U.S. adults exposed to infected animals.”
Contributed by: Paul A. Offit, MD
Researchers at the Centers for Disease and Prevention (CDC) recently reviewed details of people infected with H5N1 avian influenza virus (Garg S, Reinhart K, Couture A, et al. Highly Pathogenic Avian Influenza A (H5N1) Virus Infections in Humans. New Engl J Med. 2025 Feb 27;392(9):843-854). The authors analyzed data from 46 patients, 20 of whom were exposed to poultry, 25 of whom were exposed to infected dairy cows, and one of whom had no identified exposure.
Among the 45 patients with animal exposures, most had mild illness, none were hospitalized, and none died. A total of 42 patients (93%) had conjunctivitis, 22 (49%) had fever, and 16 (36%) had respiratory symptoms. The median duration of illness was about four days. Most patients (87%) received the antiviral drug oseltamivir. These viruses remain susceptible to the drug. There was no evidence of human-to-human spread of the virus.
The authors concluded that “In the cases identified to date, A(H5N1) viruses generally caused mild illness, mostly conjunctivitis, of short duration, predominantly in U.S. adults exposed to infected animals.”
Contributed by: Paul A. Offit, MD