Implications of the Emergence of a Novel H1 Influenza Virus

Abstract

In this issue of the Journal, there are two reports of recent transmissions of swine influenza viruses in humans. One group of viruses, described by Shinde et al.,¹ are triple reassortants of viruses from pigs, humans, and birds, called triple-reassortant swine influenza A (H1) viruses, which have circulated in pigs for more than a decade. The other group, described by the Novel Swine-Origin Influenza A (H1N1) Virus Investigation Team,² is a recent reassortant of the triple-reassortant swine influenza A (H1) viruses and a Eurasian swine influenza virus, resulting in the swine-origin influenza A (H1N1) virus (S-OIV), currently being transmitted among humans.