The information available is shown in the table.
Estimated number of adults (aged 15-59) living with HIV (both diagnosed and undiagnosed) in the UK between 2001 and 2006Estimate2006169,400200563,500200458,3002003253,000200249,500200141,200 1 From 2004 to 2006, estimates exclude individuals aged 15-59 living with HIV who were infected through blood, tissue or blood products (466 in 2006) or through mother-to-infant transmission (233 in 2006) because the proportion undiagnosed cannot be reliably estimated for these prevention groups. Numbers diagnosed include individuals with unknown exposure, allocated to each category according to the distribution of those with known exposure. These estimates (rounded to the nearest 100) with credible ranges were estimated using Multi-parameter Evidence Synthesis, in an extension of the method described in Goubar A et al. www.hpa.org.uk/infections/topics_az/hiv_and_sti/publications/cesaHPAreport.pdf. This methodology combines data from a number of sources such as the “Annual survey of HIV-infected persons accessing care, Unlinked anonymous surveillance, NATSAL 2000, ICH National Study of HIV in Pregnancy and Childhood.”2 From 2001 to 2003, no range is available for these estimates. Numbers diagnosed were adjusted for under-reporting and failure to access services. Numbers undiagnosed derived for England, Wales and Scotland using data from Natsal 2000 and the Unlinked Anonymous programme in an extension of the method previously described (Petruckevitch et al. “Genitourinary Medicine 1997; 73:348-54”). Numbers undiagnosed for Northern Ireland derived by using exposure specific factors. All cases infected through blood and blood products or tissue were assumed to be diagnosed. 3 Published estimates prior to 2005 only include persons aged 15-59. The methodology for calculating these estimates changed between 2003 and 2004 (although the key data sources were the same).Source: Health Protection Agency