Sexual transmission of HIV increasing in Catalonia - corrected

An increasing proportion of new HIV diagnoses in the Spanish region of Catalonia are due to sexual transmission, according to a report in the July 21^st edition of Eurosurveillance Weekly.

Investigators gathered data on the 2,793 cases of HIV diagnosed in the autonomous Spanish region, which includes the city of Barcelona, between 2001 and 2004. Three-quarters of the infections diagnosed during this period involved men, their median age being 38 years, with the median age of women diagnosed with HIV during this period being 35 years.

Just under a half of new infections were attributable to heterosexual transmission, with 38% of new infections involving gay men and 18% injecting drug users.

A little over a third of new infections involved individuals who were born outside Spain. The majority of these were people from areas with historic ties to the Iberian peninsula, with 39% originating from central or southern America or the Caribbean, and 26% from north west Africa. However, a significant proportion of new HIV diagnoses in Catalonia were in patients from eastern Europe (16%) or central or southern Africa (15%). Amongst recently diagnosed patients who had migrated to Spain, heterosexual transmission was the route of infection for 87% of women and 51% of men.

Information on CD4 cell counts were available for 83% of patients, and 43% of these individuals had a CD4 cell count below 200 cells/mm³ at the time their HIV was diagnosed, indicating a significant degree of immune damage and late diagnosis of HIV. Late diagnosis was most common amongst heterosexuals (55%), followed by gay men (24%) and injecting drug users (16%).

Surveillance and data concerning sexually transmitted infections suggests that there has been an increase in HIV prevalence and risk behaviour in Catalonia in recent years. Anonymous saliva samples obtained from gay men at sex venues and community-based organisations and tested for HIV suggest that HIV prevalence increased significantly from 14% in 1995 to 24% in 2004 (p < 0.05). The proportion of gay men reporting unprotected anal sex with casual and regular partners also increased during this period.

Attention is also drawn by the investigators to increases in the number of cases of chlamydia, syphilis and gonorrhoea diagnosed in Catalonia between 2001 – 2004, with new chlamydia cases increasing by almost a third, syphilis by over 100%, and gonorrohoea by 33%.

The investigators conclude that these data suggest that the mode of HIV transmission in Catalonia is changing. In much of southern Europe, injecting drug use was the principal mode of HIV infections, but the investigators suggest that sexual contact with injecting drug users, migration, more unsafe sex and sexually transmitted infections are all contributing to more sexual transmission of HIV in the Catalonia region.