HIV/AIDS surveillance in Denmark: the challenges ahead.

In Denmark, AIDS has been a mandatory reportable disease since 1983, and confirmed HIV infection has been the same since August 1990. The annual AIDS incidence increased initially and peaked in 1993 (4.6 per 100,000 inhabitants), then decreased to 1.2 per 100,000 inhabitants in 1998 and further to 0.9 in 2000. Most AIDS cases occur among men who have sex with men (MSM), representing 92% in 1980-1985 and 31% in 2000. Recently, AIDS incidence and mortality has decreased due to the new antiretroviral drugs. In 1995, 43 per million inhabitants died of AIDS, compared with 5 per million in 1998. HIV reporting in Denmark is anonymous. The annual number of new identified cases has been fairly stable at approximately 5.7 per 100,000 inhabitants. Immigrants represent 24% of identified HIV-infected persons and represent nearly 50% of all heterosexually acquired cases. Estimates show that HIV prevalence as of 2000 is 0.1% of the total population, distributed at 0.03% among heterosexuals and 4.8% among MSM. Estimated annual HIV incidence is around 5.6 per 100,000 inhabitants; three times higher among men than women, and as high as 220 per 100,000 among MSM. The spread of HIV is limited in Denmark but the prevalence is increasing due to the effect of antiretroviral therapy. This is a challenge to the existing HIV/AIDS surveillance and prevention strategy.