Aim of the study: To describe the epidemiology, longitudinally follow, test the effect of early antiretroviral treatment and investigate early events of virus-host interactions in patients with documented acute or recent HIV-1 infection in Zurich.

Study design: This is an open label, non-randomized, observational, single center study at the University Hospital Zurich, Division of Infectious Diseases and Hospital Epidemiology. We aim at enrolling approximately 300 patients over a 10 year period. All patients who fulfill the inclusion criteria of a documented acute or recent HIV infection can participate in the study. Patients are offered early combination antiretroviral treatment (cART), if treatment start falls within 90 days after diagnosis of acute HIV-infection. After one year of suppressed HIV-plasma viremia (< 50 copies/ml) patients can chose to stop cART. Patients who have not chosen to undergo early-cART, respectively will stop cART after one year will be followed for a total of 5 years. Viral setpoints reached after treatment interruptions will be compared to historic controls and to the control group not having received cART during acute infection. A battery of virological and immunological assays will be performed on blood samples obtained to better understand early virus-host interactions, which are thought to play a key role in HIV-pathogenesis research.

Summary: In summary, this study will provide comprehensive knowledge on early HIV-infection with regard to epidemiology, impact of early-cART on the course of disease and forms the base for a variety of translational research projects addressing early key pathogenesis events between virus and host, relevant for the course of disease, for transmission, for development of vaccines and new treatment strategies.

• Trial with medicinal product

• Drug: lopinavir
• Drug: atazanavir
• Drug: efavirenz
• Drug: fosamprenavir
• Drug: darunavir
• Drug: tipranavir
• Drug: ritonavir
• Drug: nevirapine
• Drug: zidovudine
• Drug: lamivudine
• Drug: tenofovir
• Drug: emtricitabine
• Drug: abacavir

• No Intervention: Patients with primary HIV-1 infection who do not want to undergo early combination antiretroviral treatment
• Active Comparator: In this arm patients with primary HIV-1 infection will receive early combination antiretroviral therapy with standard drugs approved by Swiss Medic.

Inclusion criteria:

A) Acute HIV-1 infection, defined as:

• Acute retroviral syndrome [78] (ARS) and negative or indeterminate Westernblot in the presence of a positive p24 Ag and/or detectable plasma HIV-1 RNA
• Documented seroconversion with or without symptoms within 90 days.

or

B) Recent HIV-1 infection, defined as:

• Possible ARS, positive Westernblot and detectable HIV-RNA, and a negative HIV-gp120 avidity [82, 83], respectively detuned assay [84].
• Documented acute HIV-1 infection, however, referral to our center more than 90 days after presumed date of infection.

Exclusion criteria:

• Hemoglobin < 10 g/dl (men) and < 9 g/dl (women) at the time of enrollment.