1. Department of Medicine Huddinge, Division of Infection and Dermatology, Karolinska Institutet, Karolinska University Hospital Huddinge, Stockholm, Sweden;
2. Stockholm Needle Exchange, Stockholm Centre for Dependency Disorders, Stockholm, Sweden;
3. Department of Global Public Health, Karolinska Institutet, Stockholm, Sweden;
4. Department of Monitoring and Evaluation, Public Health Agency of Sweden, Stockholm, Sweden;
5. Unit of Biostatistics, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden;
6. Centre for Psychiatry Research, Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden;
7. Stockholm Centre for Dependency Disorders, Stockholm Health Care Services, Stockholm County Council, Stockholm, Sweden