Trends in the incidence of HIV in Scotland, 1988-2009

Objectives To estimate temporal trends in HIV incidence and prevalence in Scotland, according to three main risk groups for infection: men who have sex with men (MSM), injecting drug users (IDUs) and heterosexuals.

Methods The authors extracted data for all single-and multiple-tested individuals from the national HIV test database covering the period 1980-2009 and calculated the incidence of HIV infection in each risk group and estimated RRs by fitting Poisson regression models.

Results 620 of 59 807 individuals tested positive following an initial negative HIV test, generating an overall incidence rate of 3.7/1000 person-years (95% CI 3.4 to 4.0); 60%, 20% and 37% of the 620 were associated with the risk behaviour categories MSM, IDU and heterosexual, respectively. The incidence rate among MSM in Scotland remained relatively stable between the periods < 1995 and 2005-2009 (overall: 15.3/1000 person-years, 95% CI 13.8 to 17.0), whereas the incidence among IDUs decreased between the periods < 1995 and 2005-2009, from 5.1/1000 to 1.7/1000 person-years, and also decreased among heterosexuals, from 2.9/1000 to 1.4/1000 person-years.

Conclusions The reduction in the incidence rate among IDUs suggests that harm reduction measures initiated from the late 1980s were effective in reducing HIV transmission in this risk group; however, the absence of a reduction in HIV incidence rates among MSM is disappointing and highlights the need for renewed efforts in the prevention of HIV in this major risk group.