First Human Infection with Influenza A(H1N2)v Virus - Yunnan Province, China, 2026

Human infections with influenza A(H1N2)v viruses of swine origin have been sporadically reported in several countries, usually following direct or indirect exposure to pigs or contaminated environments. However, sustained human-to-human transmission has not yet been documented.

This report describes the first laboratory-confirmed human infection with the influenza A(H1N2)v virus in China. Whole-genome sequencing showed that all eight gene segments were closely related to influenza viruses of swine origin circulating in China. No secondary human cases were identified among the close contacts, and no evidence of sustained human-to-human transmission was detected.

This highlights the importance of routine influenza-like illness surveillance, timely whole-genome sequencing, and systematic investigation of unusual influenza A infections. Strengthened surveillance at the human-animal interface and cross-sector collaboration under the One Health framework are essential for early detection and risk assessment of variant influenza viruses.