The Centers for Disease Control and Prevention (CDC) has confirmed the first-ever case of avian influenza A(H5N1), commonly known as H5N1 bird flu, in a child in the United States.
The young patient, a resident of California, experienced mild symptoms and is now recovering after receiving antiviral flu treatment.
Initial tests on the child’s specimen revealed low levels of the H5N1 virus, but follow-up testing several days later showed no trace of the virus. However, the CDC noted that the child tested positive for other common respiratory viruses, suggesting a possible mixed infection.
While the infection raised alarms, health officials emphasize that there is no evidence of person-to-person transmission of H5N1 in this case.
To date, human-to-human spread of the bird flu virus has not been documented in the United States, even with the small number of human cases previously reported.
The California Department of Public Health (CDPH) has launched a comprehensive investigation to identify the source of the child’s exposure.
The effort includes testing all household members, who also reported similar symptoms. Results confirmed that none of the child’s family members were infected with H5N1, although some tested positive for the same common respiratory viruses found in the child.
The CDC credited its routine influenza surveillance systems for identifying the case, marking this as the second human H5N1 infection detected in the U.S. through these monitoring efforts.
California has been a focal point for H5N1 activity since outbreaks began affecting wild birds and domestic poultry in 2022. The state also faced a surge in cases affecting dairy herds starting in August 2024.
This year alone, 55 human cases of H5N1 bird flu have been reported in the U.S., with 29 of them occurring in California.
While the confirmation of a child case has prompted concern, the CDC continues to reassure the public that the overall risk of widespread transmission remains low.
Human infections with H5N1 bird flu remain rare worldwide. However, when they do occur, they are often associated with close contact with infected birds or contaminated environments.
Despite its limited reach in humans, the virus has gained attention for its high mortality rate in confirmed cases globally.
In response to the ongoing threat of bird flu, the United States government has invested heavily in vaccine development.
In July, the U.S. Department of Health and Human Services awarded vaccine manufacturer Moderna $176 million to create a new mRNA vaccine targeting H5N1.
The vaccine, which uses the same mRNA technology as Moderna’s COVID-19 vaccine, is being developed as a proactive measure against potential outbreaks.
