title: Molecular analysis allows inference into HIV transmission among young men who have sex with men in the United States.
abstract: OBJECTIVE
  The objective of this study is to understand the spread of HIV among and between age and racial/ethnic groups of men who engage in male-to-male sexual contact (MSM) in the United States.
  
  
  METHODS
  An analysis of HIV-1 pol sequences for MSM collected through the US National HIV Surveillance System (NHSS) during 2001-2012.
  
  
  METHODS
  Pairwise genetic distance was calculated to determine potential transmission partners (those with very closely related nucleotide sequences, i.e. distance ≤1.5%). We described race/ethnicity and age of potential transmission partners of MSM.
  
  
  RESULTS
  Of 23 048 MSM with HIV sequences submitted to NHSS during 2000-2012, we identified potential transmission partners for 8880 (39%). Most potential transmission partners were of the same race/ethnicity (78% for blacks/African-Americans, 64% for whites and 49% for Hispanics/Latinos). This assortative mixing was even more pronounced in the youngest age groups. Significantly fewer young black/African-American and Hispanic/Latino MSM had older potential transmission partners than young white MSM.
  
  
  CONCLUSIONS
  Black/African-American MSM, who are more profoundly affected by HIV, were more likely to have potential HIV transmission partners who were of the same race/ethnicity and similar in age, suggesting that disparities in HIV infections are in large part not due to age-disassortative relationships. Concerted efforts to increase access to preexposure prophylaxis, quality HIV care and effective treatment are needed to interrupt transmission chains among young, black/African-American MSM.
authors.affiliation: aDivision of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention bICF International, Atlanta, Georgia cDepartment of Medicine, University of California, San Diego, California, USA.
authors.forename: Y Omar
authors.initials: YO
authors.lastname: Whiteside
authors.forename: Ruiguang
authors.initials: R
authors.lastname: Song
authors.forename: Joel O
authors.initials: JO
authors.lastname: Wertheim
authors.forename: Alexandra M
authors.initials: AM
authors.lastname: Oster
mesh_terms: D000293:Adolescent; D000367:Age Factors; D018562:Disease Transmission, Infectious; D005006:Ethnicity; D005838:Genotype; D015658:HIV Infections / Q000453:epidemiology / Q000635:transmission* / Q000821:virology*; D015497:HIV-1 / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D018451:Homosexuality, Male; D006801:Humans; D008297:Male; D017720:Molecular Epidemiology; D017422:Sequence Analysis, DNA; D014481:United States / Q000453:epidemiology; D055815:Young Adult; D054302:pol Gene Products, Human Immunodeficiency Virus / Q000235:genetics
chemical_list: D054302:pol Gene Products, Human Immunodeficiency Virus