title: Evidence for frequent reinfection with human immunodeficiency virus type 1 of a different subtype.
abstract: A major premise underlying current human immunodeficiency virus type 1 (HIV-1) vaccine approaches is that preexisting HIV-1-specific immunity will block or reduce infection. However, the recent identification of several cases of HIV-1 reinfection suggests that the specific immune response generated for chronic HIV-1 infection may not be adequate to protect against infection by a second HIV-1 strain. It has been unclear, though, whether these individuals are representative of the global epidemic or are rare cases. Here we show that in a population of high-risk women, HIV-1 reinfection occurs almost as commonly as first infections. The study was designed to detect cases of reinfection by HIV-1 of a different subtype and thus captured cases where there was considerable diversity between the first and second strain. In each case, the second virus emerged approximately 1 year after the first infection, and in two cases, it emerged when viral levels were high, suggesting that a well-established HIV-1 infection may provide little benefit in terms of immunizing against reinfection, at least by more-divergent HIV-1 variants. Our findings indicate an urgent need for studies of larger cohorts to determine the incidence and timing of both intersubtype and intrasubtype reinfection.
authors.affiliation: Division of Human Biology, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave N., C3-168, Seattle, WA 98109-1024, USA.
authors.forename: Bhavna
authors.initials: B
authors.lastname: Chohan
authors.forename: Ludo
authors.initials: L
authors.lastname: Lavreys
authors.forename: Stephanie M J
authors.initials: SM
authors.lastname: Rainwater
authors.forename: Julie
authors.initials: J
authors.lastname: Overbaugh
mesh_terms: D000163:Acquired Immunodeficiency Syndrome / Q000821:virology*; D005260:Female; D015497:HIV-1 / Q000145:classification* / Q000235:genetics; D006801:Humans; D011995:Recombination, Genetic; D012008:Recurrence