Overview

• No new human H5N1 bird flu cases have been confirmed in the U.S. since early February 2025, following 70 reported infections over 14 months.
• Health officials suggest the decline may be linked to natural seasonality, with infections peaking in fall and winter due to wild bird migration patterns.
• Surveillance challenges, including government lab staffing cuts and immigrant farmworker hesitancy to seek testing, may contribute to underreporting.
• The CDC maintains that public risk remains low but warns of moderate pandemic potential if the virus mutates further.
• Ongoing research, including serological studies of dairy workers and cats, aims to uncover undetected cases and assess broader exposure trends.