Two human infections with influenza A(H1N2) variant (A(H1N2)v) virus were reported by the Michigan Department of Health and Human Services.

The patients, who are <18 years of age, initially developed illness and sought healthcare during the week ending August 15, 2026 (Week 32). The patients were not hospitalized, one patient received influenza antiviral treatment, and both are recovering from their illnesses. Investigation by local and state public health officials identified that both patients, who have not had contact with one another, had attended the same agricultural fair where ill swine were present prior to their illness onset. No additional cases of human infection with A(H1N2)v virus associated with these cases or the fair have been identified.

These are the third and fourth human infections with a variant influenza virus reported in the 2025-2026 season; all four have been influenza A(H1N2)v viruses.

When an influenza virus that normally circulates in swine (but not people) is detected in a person, it is called a “variant” influenza virus. Most human infections with variant influenza viruses occur following exposure to swine, but human-to-human transmission can occur. It is important to note that in most cases, variant influenza viruses have not shown the ability to spread easily and sustainably from person to person.