AIDS Cases by Transmission Group and Year of Diagnosis
| 1987 | 1988 | 1989 | 1990 | 1991 | 1992 | |
| Homo/Bisexual | 66 | 62 | 73 | 101 | 92 | 79 |
| Intravenous Drug User (IDU) | 19 | 7 | 29 | 38 | 55 | 79 |
| Homo/IDU | 1 | 2 | 3 | 1 | 1 | 5 |
| Heterosexual | 38 | 29 | 48 | 63 | 64 | 77 |
| Haemophiliac | 14 | 8 | 5 | 4 | 5 | 4 |
| Transfusion | 5 | 5 | 10 | 14 | 12 | 9 |
| Mother to Child | 2 | 3 | 6 | 4 | 3 | |
| Unknown | 3 | 6 | 11 | 6 | 13 | 9 |
| Total | 148 | 119 | 182 | 233 | 246 | 265 |
In 1990 and unlike other southern European countries AIDS in Portugal was not mainly a disease of drug intravenous addicts, but since then the picture was changed. In 1992 their weight was 30% and the partial data for 1993 seems to indicate a new increase to 40%. Because this and after a long delay the government start a syringe and needle exchange in October 1993.
AIDS Cases and Intravenous Drug Users Weight
| 1987 | 1988 | 1989 | 1990 | 1991 | 1992 | |
| Intravenous Drug Users | 13% | 6% | 16% | 16% | 22% | 30% |
| Others | 87% | 94% | 84% | 84% | 78% | 70% |
In 1989 51% of the addicts visiting the treatment units had shared their works during the last month. And only 24% used condoms, usually in a irregular basis. By 1992 71% said they had not shared syringes or needles in the last six months, and 60% used condoms, although it is still done in irregular basis. In 1995 only 5% of intravenous drug addicts the share of works during the last month.
Sources: António Costa, Treatment of Heroin Addicts and HIV Epidemiology in Portugal, Centro das Taipas, Colectânea de Textos, VI volume, Lisboa 1994, SPTT.