CDC confirms H5N1 bird flu infection in a child in California

The Centers for Disease Control and Prevention (CDC) has confirmed a human infection with avian influenza A(H5N1) (H5N1 bird flu) in a child in California. This is the first reported avian influenza H5 virus infection in a child in the United States. Consistent with previously identified human cases in the United States, the child reportedly experienced mild symptoms and received antiviral medications for the flu. Low levels of viral material were detected in the first sample collected, and follow-up tests of the child several days later were negative for H5 bird flu, but were positive for other common respiratory viruses. The child recovers from his illness. An investigation is ongoing by the California Department of Public Health (CDPH) into the child’s possible source of H5N1 exposure.

During CDPH’s investigation, all household members reported having symptoms and samples were collected from those people. All test results from household members were negative for H5 bird flu, and some household members were positive for the same common respiratory viruses as the child. Contact tracing continues, but there is currently no evidence of person-to-person spread of H5N1 bird flu from this child to others. To date, no person-to-person spread has been identified associated with the H5N1 bird flu cases reported in the United States.

This case was discovered through influenza testing and reported to CDPH through influenza surveillance. This is the second case in the US identified through national surveillance. The CDC continues to closely monitor available data from influenza surveillance systems, especially in states affected by outbreaks in animals, including California, where widespread outbreaks of H5N1 avian flu have been observed in wild birds and domestic poultry since 2022 and since August 2024 in dairy herds. stands.

Limited and sporadic human infections with avian influenza virus H5N1, where animal exposure has not been identified, are very uncommon but have occurred, mainly in countries other than the United States. These cases underscore the importance of continued surveillance and investigation at the local, state, and federal levels. Including this most recent case, 55 human cases of H5 bird flu have now been reported in the United States in 2024, 29 of which were in California.

CDC’s risk assessment for the general public is low. However, people who have been exposed to infected or potentially infected animals, such as birds, dairy cattle, or other animals (including livestock), or to environments contaminated by infected birds or other animals, are at greater risk of infection. CDC recommends avoiding unprotected exposure to sick or dead animals, including wild birds, poultry, other domestic birds, and other wild or domesticated animals (including cows).

CDC will continue to provide updates as additional information becomes available. For more information, read California’s statement, State Reports Single, Possible Case of Bird Flu Virus in Children with Mild Symptoms