Home Emergency Medicine Human A(H5N1) Cases Generally Have Mild Illness, With Short Duration

Human A(H5N1) Cases Generally Have Mild Illness, With Short Duration

Forty-five of 46 case patients were exposed to infected poultry or infected/presumed infected dairy cows

By Elana Gotkine HealthDay Reporter

THURSDAY, Jan. 2, 2025 (HealthDay News) — The A(H5N1) virus generally causes mild illness of short duration, mainly among U.S. adults exposed to infected animals, according to a study published online Dec. 31 in the New England Journal of Medicine.

Shikha Garg, M.D., from the U.S. Centers for Disease Control and Prevention in Atlanta, and colleagues analyzed data from persons with laboratory-confirmed A(H5N1) virus infection to describe the characteristics of cases identified from March through October 2024 in the United States.

The researchers found that 20, 25, and one of the case patients were exposed to infected poultry, exposed to infected or presumably infected dairy cows, and had no identified exposure, respectively. All 45 cases with animal exposure had mild A(H5N1) illness; none were hospitalized and none died. Overall, 93, 49, and 36 percent of patients had conjunctivitis, fever, and respiratory symptoms, respectively; 33 percent of patients had conjunctivitis only. Among the 16 patients with available data, the median duration of illness was four days. Eighty-seven percent of the patients received oseltamivir, which was started a median of two days after onset of symptoms. Among the 97 household contacts of case patients with animal exposure, there were no additional cases identified. Workers exposed to infected animals most often used gloves, eye protection, and face masks (71, 60, and 47 percent, respectively).

“Public health efforts should continue to focus on protecting workers exposed to infected animals through implementation of prevention measures on farms, including personal protective equipment use, and ongoing monitoring, early testing, and prompt antiviral treatment,” the authors write.


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