Influenza A(H3N2) Variant Virus Outbreak at Three Fairs - Maryland, 2017.

What is already known about this topic? Outbreaks of variant influenza have occurred in agricultural fair settings in the United States. What is added by this report? In September 2017, 40 cases of influenza A(H3N2) variant virus infection were identified among persons with swine exposure at one of three Maryland agricultural fairs. Thirty cases (75%) occurred among persons at high risk for serious influenza complications. Thirty-five percent of patients reported only indirect swine contact. What are the implications for public health practice? Increased public education that groups at high risk for influenza complications should avoid pigs and swine barns is needed. When swine influenza virus is detected at one fair, enhanced surveillance should extend to all fairs in the region.