[New cases of HIV infection. Estimation of the time of transmission]

During 1991 and 1992, 107 HIV infections were diagnosed at Ullevål hospital, Oslo. Previously collected serum specimens from 53 of these persons were tested with different anti-HIV and HIV antigen tests. Some of the sera were also examined for HIV RNA using PCR. Based on these results, the intervals between the last HIV negative and the first positive samples, and between the first HIV positive sample and the HIV diagnosis, were calculated. 38 persons had delivered HIV negative samples before their first positive sample. In addition, eight persons had a sample with serological markers of recent infection. For these 46 persons, the median time between the last HIV negative sample and the diagnosis was one year. 36 of them were HIV negative three years before diagnosis. For 19 persons, markers of HIV infection were detected in samples taken before the disease was first diagnosed. For two persons HIV markers were present in samples taken as early as 1986.