Update: Influenza Activity--United States and Worldwide, May 24-September 5, 2015

During May 24–September 5, 2015, the United States experienced typical low levels of seasonal influenza activity. Influenza A (H1N1)pdm09 (pH1N1), influenza A (H3N2), and influenza B viruses were detected worldwide and were identified sporadically in the United States. All of the influenza viruses collected from U.S. states and other countries during that time have been characterized antigenically and/or genetically as being similar to the influenza vaccine viruses recommended for inclusion in the 2015–16 Northern Hemisphere vaccine. During May 24–September 5, 2015, three influenza variant† virus infections were reported; one influenza A (H3N2) variant virus (H3N2v) from Minnesota in July, one influenza A (H1N1) variant (H1N1v) from Iowa in August, and one H3N2v from Michigan in August.