The fate of a Canadian teenager who was infected with H5N1 bird flu in early November, and subsequently admitted to an intensive care unit, has finally been revealed: She has fully recovered.
But genetic analysis of the virus that infected her body showed ominous mutations that researchers suggest potentially allowed it to target human cells more easily and cause severe disease — a development the study authors called “worrisome.”
The case was published Tuesday in a special edition of the New England Journal of Medicine that explored H5N1 cases from 2024 in North America. In one study, doctors and researchers who worked with the Canadian teenager published their findings.
In the other, public health officials from across the U.S. — from the Centers for Disease Control and Prevention, as well as state and local health departments — chronicled the 46 human cases that occurred between March and October.
There have been a total of 66 reported human cases of H5N1 bird flu in the U.S. in 2024.
In the case of the 13-year-old Canadian child, the girl was admitted to a local emergency room on Nov. 4 having suffered from two days of conjunctivitis (pink eye) in both eyes and one day of fever.
The child, who had a history of asthma, an elevated body-mass index and Class 2 obesity, was discharged that day with no treatment.
Over the next three days, she developed a cough and diarrhea and began vomiting. She was taken back to the ER on Nov. 7 in respiratory distress and with a condition called hemodynamic instability, in which her body was unable to maintain consistent blood flow and pressure. She was admitted to the hospital.
On Nov. 8, she was transferred to a pediatric intensive care unit at another hospital with respiratory failure, pneumonia in her left lower lung, acute kidney injury, thrombocytopenia (low platelet numbers) and leukopenia (low white blood cell count).
She tested negative for the predominant human seasonal influenza viruses — but had a high viral loads of influenza A, which includes the major human seasonal flu viruses, as well as H5N1 bird flu. This finding prompted her caregivers to test for bird flu; she tested positive.
