Background: Considerable problems in the management of HIV infection remain, even in the Western world. Not all patients respond satisfactorily to expensive highly active antiretroviral therapy (HAART). Relapses are frequent; often, but not always related to drug resistance, and side effects may be serious. New therapeutic strategies are therefore needed.

Material and methods: A systematic survey was made of protocols for gene therapy available in major databases, as well as of publications on gene therapy of HIV infection and other virus infections.

Results: A number of strategies for gene therapy in HIV infection are theoretically possible, several of which are already in phase I trials, in a few cases also in phase II trials. Several strategies are targeting various aspects of the life cycle of HIV, while others are aiming at improving the patient's own immune response to the virus. So far no clinical results have been published. Gene therapy is also in development for certain other viruses, including various herpes viruses as well as hepatitis B and C viruses. Gene therapy for cytomegalovirus retinitis with synthetic oligonucleotides based on the antisense principle is already available in clinical medicine.

Interpretation: Valuable information has been gained from the studies, which will be a great value in the further development of gene therapy for HIV infection and for other viral infections.