Lead
The Swiss HIV Cohort Study (www.shcs.ch) is a multicenter, clinic based longitudinal study enrolling HIV infected individuals in Switzerland. It aims at performing research in the field of HIV medicine, basic and social sciences and public health. It started 1988, includes ~19000 patients, is instrumental for the high quality of HIV-care in Switzerland, for monitoring the HIV epidemic and co-infections, and has contributed to better understanding interactions between HIV and the human host.

Lay summary
The SHCS is a fully established cohort that was started in 1988. Since then, ~19000  patients were enrolled and in 2013, almost 9000 were followed actively. From the beginning, the SHCS was an open, longitudinal cohort, enrolling continuously individuals from all transmission groups. In 2003 the “Swiss Mother and Child HIV Cohort Study” (MoCHiV) was integrated into the SHCS. Early on, the SHCS unified clinical, translational, basic, social and epidemiological science, as well more recently also nursing research. The considerable scientific impact of the SHCS and MoCHiV is illustrated by more than 700 publications in peer reviewed journals that directly emerged from these studies, respectively were made possible by significant contributions of the SHCS. One of the hallmarks of the SHCS is that this research network was able to rapidly respond to new scientific findings and challenges in the field. The SHCS is nationwide highly representative. At least 45% of all HIV-infected individuals living in Switzerland, 75% of all patients with AIDS and 75% of all patients on antiretroviral treatment participate in the SHCS. The SHCS has a strong impact on public health in Switzerland and includes: (i) Providing high quality data on HIV transmission, (ii) preventing HIV-transmission by optimal treatment and counseling, (iii) informing care givers on optimal screening and treatment interventions, (iv) providing key data on how to prevent and treat opportunistic infections, (v) monitoring co-infections and other  sexually transmitted infections (STI), (vi) providing behavioral data on sexual activities, on prevention measures, substance abuse, depression prevalence, employment status, and activities of daily living, (vii) performing cost effectiveness studies with regard to diagnostic procedures, (viii) monitoring transmission of HIV drug resistance, (ix) continuously delivering high quality data for prevention campaigns, (x) providing feedback to physicians on treatment outcome and mortality compared to other settings.