Oceania is a geographical region in the South Pacific consisting of 15 countries and 20 dependent territories that are grouped into the subregions of Australasia, Melanesia, Micronesia, and Polynesia. Oceania exhibits extreme cultural, linguistic, and environmental diversity, and most countries have very small populations that are highly mobile and dispersed over wide areas. Although data are sparse, every country and dependency in Oceania aside from Niue, Tokelau, and Pitcairn Islands has reported cases of human immunodeficiency virus (HIV), though the region's only generalized epidemic occurs in Papua New Guinea (PNG). With the exception of Australasia, Oceania is experiencing rapid social change and many factors including migration, low levels of development, high rates of sexually transmitted infections (STIs), widespread unsafe sexual practices, and political instability predispose ...