Most HIV-1 genetic subtypes have entered Sweden

Objective: The aim of this study was to document which genetic subtypes of HIV-1 have entered Sweden and to study transmission patterns of these virus variants. Patients: All HIV-1-infected individuals at Danderyds Hospital, Stockholm, Sweden, who were suspected of carrying a virus of African origin were prospectively included in the study. The study subjects originated from 15 different African countries. Methods: The V3 domain of the HIV-1 envelope was directly sequenced from uncultured peripheral blood mononuclear cells from 75 individuals included in the study. Phylogenetic analyses were used to determine genetic subtype and to study transmission patterns. Results: The virus strains carried by the study subjects belonged to six established subtypes of HIV-I (27A, 4B, 18C, 18D, 2G, 2H). Two individuals from Zaire carried a subtype, which had not been classified previously, provisionally named subtype J. Eleven transmissions of non-subtype B strains in Sweden were documented. Conclusions: This study shows that most genetic HIV-I subtypes have entered Sweden despite the relatively low prevalence of HIV infection in the country. Thus, the complete dominance of subtype-B infections which was seen during the early phase of the HIV-1 epidemic in Europe and the US has been broken in Sweden.