One human infection with an influenza A(H1N2) variant (A(H1N2)v) virus was reported by Ohio. The patient is <18 years of age, was not hospitalized, and has completely recovered from their illness. The patient and the household contacts of the patient report no swine contact or attendance at agricultural exhibits where swine were present. It is possible that limited human-to-human transmission occurred. No ongoing human-to-human transmission has been identified. This is the third influenza A(H1N2)v virus identified in the United States that occurred in 2021.
When an influenza virus that normally circulates in swine (but not people) is detected in a person, it is called a “variant influenza virus”. Ten human infections with a novel influenza A virus have been reported in the United States this influenza season, including two H3N2v (IA, WI), three H1N2v (IA, OH (2)), and five H1N1v (IA, NC, WI (3)) virus infections. Six infections have occurred in children <18 years of age and four have occurred in adults ≥ 18 years of age. Of the ten infected individuals, only one had no identified connection to swine. The other nine individuals had direct contact with swine, were on a property with swine present, or had a household member who had direct contact with swine prior to illness onset.
Early identification and investigation of human infections with novel influenza A viruses are critical so that the risk of infection can be more fully understood and appropriate public health measures can be taken. Additional information on influenza in swine, variant influenza virus infection in humans, and strategies to interact safely with swine can be found at www.cdc.gov/flu/swineflu/index.htm. Additional information regarding human infections with novel influenza A viruses can be found at http://gis.cdc.gov/grasp/fluview/Novel_Influenza.html.