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.