The main objective is to access efficacy of first and second line antiretroviral therapy (ART) and its determinants in patients treated at the Komfo Anokye Teaching Hospital in Kumasi (KATH), Ghana, and to compare the clinical, virological and immunological efficacy of second line ART in patients who were switched after virological failure compared to patients who were switched after clinical or immunological failure. Other specific study objectives are: 1. To establish an HIV Cohort Study at the study site. 2. To assess the rate of virological failure among patients on first line therapy 3. To compare the clinical, immunological and virological efficacy of second line antiretroviral therapy amongst patients randomised to virological monitoring whilst on first line compared with those monitored routinely using clinical and immunological monitoring. 4. To assess the incidence and outcome of tuberculosis (TB) and other opportunistic infections in patients treated at the Komfo Anokye Teaching Hospital HIV services 5. To obtain parameters for quality of care, e. g. performance of TB screening procedures 6. To develop strategies to minimise treatment failures, on the basis of the results of the study 7. To generate a large prospective second-line ART cohort, to serve as basis for further research projects 8. To implement point-of-care viral load analysis at the Komfo Anokye Teaching Hospital 9. Capacity building: epidemiology, medical documentation and data base management. Enrollment of one PhD and one Master student
Inclusion Criteria: * able and willing to give informed written consent * age \> 18 years * on first line ART since \> 12 months Exclusion Criteria: * not willing or able to comply with study procedures