A child in California has been infected with H5N1 avian flu, the Centers for Disease Control and Prevention (CDC) has confirmed. This is the first such case reported in a minor in the US and brings the total number of confirmed human cases in 2024 to 55. 

CDC figures as of November 22, 2024, show that human H5N1 infections have been confirmed in seven US states. California, where the child resides, has seen the most, with 29. All bar one of these infections have been sourced to infected cattle. 

The H5N1 bird flu virus began circulating in wild bird and poultry populations, but in recent years outbreaks of a highly pathogenic strain of the disease have been seen in a host of different mammal species too, and in some of the farthest-flung corners of our planet. 

Dairy farms across the US have been seeing outbreaks of H5N1 throughout this year. The first such outbreaks in California were reported in August 2024, and the first human cases followed swiftly in October. People working closely with infected cattle are at risk of exposure to the virus either from direct contact with the animals, or from contaminated surfaces or raw milk, so the CDC recommends a range of precautions including the wearing of personal protective equipment (PPE).

For the wider public, the current public health risk is still deemed “low” by the agency, and no person-to-person transmission has yet been confirmed. People are advised to keep their distance from wild birds as much as possible, to avoid contact with dead birds and to report any sightings to state or federal authorities, and to avoid consuming unpasteurized milk. 

The child who tested positive for H5N1 in California was confirmed by the state’s Department of Public Health (CDPH) as having mild symptoms and was said to be recovering at home after receiving treatment. A repeat test four days later was negative, and the CDC confirmed that the amount of viral material in the initial sample was low. 

Tests also found that the child, and some family members, were infected with other common respiratory viruses that could also have accounted for their symptoms. No member of the household tested positive for H5N1, so there remains no evidence of onward transmission. 

It’s not totally clear how the child was exposed to the virus in the first place, but investigations are ongoing.

The CDC notes that this case is the second to have been identified so far through the national surveillance program. While the agency emphasizes that it “continues to closely monitor available data” to keep tabs on the outbreaks, some scientists have been critical of the response, claiming that the US is failing to learn lessons from COVID-19 in the face of another disease with pandemic potential. 

There’s no doubt that the continued spread of this virus is alarming, and that it poses a potentially grave risk to public health, but the message from experts is that there’s no cause for panic. Precautionary measures are being enacted in various regions, including bolstering vaccine stocks – our existing knowledge of how to create effective flu vaccines is just one way in which this situation differs from the early days of COVID. 

“It’s natural for people to be concerned,” acknowledged CDPH Director and State Public Health Officer Dr Tomás Aragón, “and we want to reinforce for parents, caregivers and families that based on the information and data we have, we don’t think the child was infectious – and no human-to-human spread of bird flu has been documented in any country for more than 15 years.”