title: HIV incidence in men who have sex with men in England and Wales 2001-10: a nationwide population study.
abstract: BACKGROUND
  Control of HIV transmission could be achievable through an expansion of HIV testing of at-risk populations together with ready access and adherence to antiretroviral therapy. To examine whether increases in testing rates and antiretroviral therapy coverage correspond to the control of HIV transmission, we estimated HIV incidence in men who have sex with men (MSM) in England and Wales since 2001.
  
  
  METHODS
  A CD4-staged back-calculation model of HIV incidence was used to disentangle the competing contributions of time-varying rates of diagnosis and HIV incidence to observed HIV diagnoses. Estimated trends in time to diagnosis, incidence, and undiagnosed infection in MSM were interpreted against a backdrop of increased HIV testing rates and antiretroviral-therapy coverage over the period 2001-10.
  
  
  RESULTS
  The observed 3·7 fold expansion in HIV testing in MSM was mirrored by a decline in the estimated mean time-to-diagnosis interval from 4·0 years (95% credible interval [CrI] 3·8-4·2) in 2001 to 3·2 years (2·6-3·8) by the end of 2010. However, neither HIV incidence (2300-2500 annual infections) nor the number of undiagnosed HIV infections (7370, 95% CrI 6990-7800, in 2001, and 7690, 5460-10 580, in 2010) changed throughout the decade, despite an increase in antiretroviral uptake from 69% in 2001 to 80% in 2010.
  
  
  CONCLUSIONS
  CD4 cell counts at HIV diagnosis are fundamental to the production of robust estimates of incidence based on HIV diagnosis data. Improved frequency and targeting of HIV testing, as well as the introduction of ART at higher CD4 counts than is currently recommended, could begin a decline in HIV transmission among MSM in England and Wales.
  
  
  BACKGROUND
  UK Medical Research Council, UK Health Protection Agency.
authors: MRC Biostatistics Unit, Institute of Public Health, Cambridge, UK.
authors: Paul J
authors: PJ
authors: Birrell
authors: O Noel
authors: ON
authors: Gill
authors: Valerie C
authors: VC
authors: Delpech
authors: Alison E
authors: AE
authors: Brown
authors: Sarika
authors: S
authors: Desai
authors: Tim R
authors: TR
authors: Chadborn
authors: Brian D
authors: BD
authors: Rice
authors: Daniela
authors: D
authors: De Angelis
mesh_terms: D000328:Adult; D019380:Anti-HIV Agents / Q000008:administration & dosage*; D015496:CD4-Positive T-Lymphocytes; D004334:Drug Administration Schedule; D004739:England / Q000453:epidemiology; D015658:HIV Infections / Q000175:diagnosis* / Q000188:drug therapy / Q000453:epidemiology* / Q000276:immunology / Q000635:transmission; D018451:Homosexuality, Male; D006801:Humans; D015994:Incidence; D018655:Lymphocyte Count; D008297:Male; D008403:Mass Screening / Q000379:methods; D008875:Middle Aged; D012747:Sexual Partners; D014852:Wales / Q000453:epidemiology
chemical_list: D019380:Anti-HIV Agents
references: AIDS. 2010 Jan 16;24(2):271-82
references: 20010072
references: PLoS One. 2010 Jun 10;5(6):e11068
references: 20548786
references: Lancet. 2010 Aug 14;376(9740):532-9
references: 20638713
references: J Infect Dis. 2004 Sep 1;190(5):879-85
references: 15295691
references: AIDS. 2008 May 31;22(9):1071-7
references: 18520351
references: J Int AIDS Soc. 2009 Sep 18;12:19
references: 19761622
references: Lancet. 2000 Apr 1;355(9210):1131-7
references: 10791375
references: AIDS. 2010 Aug 24;24(13):2109-15
references: 20616697
references: AIDS. 2001 Jul 27;15(11):1409-15
references: 11504962
references: Biostatistics. 2011 Oct;12(4):666-81
references: 21525422
references: Open AIDS J. 2012;6:149-55
references: 23049663
references: HIV Med. 2012 Sep;13 Suppl 2:1-85
references: 22830364
references: PLoS One. 2012;7(2):e29098
references: 22347994
references: MMWR Morb Mortal Wkly Rep. 2011 Dec 2;60(47):1618-23
references: 22129997
references: Euro Surveill. 2010 Dec 02;15(48):
references: 21144450
references: J Infect Dis. 2007 Apr 1;195(7):951-9
references: 17330784
references: PLoS One. 2010 Jun 07;5(6):e10991
references: 20539817
references: AIDS. 2012 Apr 24;26(7):893-6
references: 22313960
references: Sex Transm Dis. 2011 Aug;38(8):685-90
references: 21844719
references: Lancet. 2009 Jan 3;373(9657):48-57
references: 19038438
references: Commun Dis Public Health. 2000 Dec;3(4):277-81
references: 11280259
references: AIDS. 2005 Jun 10;19(9):961-8
references: 15905678
references: AIDS. 2006 Jun 26;20(10):1447-50
references: 16791020
references: AIDS. 2010 Nov 27;24(18):2849-58
references: 20962617
references: Euro Surveill. 2012 Jul 19;17(29):
references: 22835469
references: Commun Dis Rep CDR Rev. 1995 Nov 10;5(12):R183-6
references: 8541940
references: PLoS Med. 2012;9(7):e1001260
references: 22802740
references: JAMA. 2008 Aug 6;300(5):520-9
references: 18677024
references: Clin Infect Dis. 2011 Mar 15;52(6):793-800
references: 21367734
references: Sex Transm Infect. 2013 May;89(3):207-11
references: 23015689
references: Clin Infect Dis. 2010 Aug 15;51(4):392-400
references: 20617921
references: Sex Transm Dis. 2011 Mar;38(3):221-9
references: 20921930