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Epidemiology, Biostatistics and Prevention Institute

A multicenter, observational cohort to study the characteristics of individuals asking for pre-exposure prophylaxis (PrEP) and the incidence of HIV and STIs: «The Swiss PrEPared Study»

«Pre-exposure prophylaxis» (PrEP) refers to the use of an antiretroviral medication to prevent HIV negative people from acquiring the infection and is an effective measure to complement existing HIV prevention strategies among populations with a high risk of HIV infection. Despite its lack of formal approval in Switzerland, PrEP use needs to be monitored carefully for multiple reasons:

A growing number of people in Switzerland already use PrEP bought online, often without medical supervision. This puts PrEP users not only at risk of drug-related side effects (such as kidney failure), but may also lead to subsequent viral resistance in those taking PrEP despite a latent, undiagnosed HIV infection.

Another concern is that PrEP might result in changes in sexual behavior: PrEP use is associated with an increase in condomless sex, which may in turn facilitate the transmission of other sexually transmitted infections (STIs).

Finally, sexual minorities have been found to suffer from a higher rate of depression, suicide and problematic substance use, which further underlines the need for appropriate care and mental health screening. The prospective cohort study SwissPrEPared aims to longitudinally follow people at risk of HIV who seek PrEP, over a period of 3 years. The SwissPrEPared Study is nested within the «SwissPrEPared Program», which is a nation-wide prevention program for the surveillance and exchange of experiences related to PrEP. The goal of the program is to ensure high quality care for individuals seeking PrEP. The main objectives of the SwissPrEPared Study will be:

  1. To obtain epidemiological data on PrEP seekers: to determine the extent and modalities of PrEP use; to assess and monitor the occurrence of STIs (such as HIV, syphilis, hepatitis B and C, gonorrhea, chlamydia, and mycoplasma genitalium); 

  2. To assess the mental and sexual well-being of this particular population using a questionnaire specifically designed for the SwissPrEPared program (assessment of sexual behavior, factors associated with increased sexual risk taking, presence of psychiatric disorders (depression, substance abuse), influence of geosocial networking apps on sexual well-being). 
 The SwissPrEPared study will be conducted at 7 hospitals, 4 Checkpoints (sexual health clinics), and 2 private health care facilities. We estimate 4’000 individuals to qualify for PrEP in Switzerland.

Ultimately, the SwissPrEPared Program and nested study intend to provide a better understanding of the needs, expectations and vulnerabilities of individuals seeking PrEP. With better-targeted prevention measures and improved access to care, HIV incidence rates may further decrease in Switzerland. Also, through systematic HIV screening at entry, the SwissPrEPared program will help identify HIV-infected individuals unaware of their condition and thus bring a substantial contribution to reaching the UNAIDS 90% targets (i.e. 90% of people living with HIV are informed about their HIV status; 90% of people diagnosed with HIV receive sustained antiretroviral treatment (ART); 90% of all people on ART have viral suppression).


For more information and to participate please visit the project page.

Weiterführende Informationen



Benjamin Hampel (Project Leader)
Jan Fehr (Project Leader)
Andrea Farnham
Frederique Lachmann
Natalie Messerli
Matthias Reinacher
Maryline Rothen
Adriana Rüegger
Manuela Rasi
Babette Winter