In 2015 there were about 37 million people living with HIV worldwide, 69% of them in sub-Sahara Africa. There were 2 million people newly infected with HIV this year, 95% of them in countries with low or middle-income and 1.2 million people died as a result of HIV and AIDS. The
Federal Office of Public Health (BAG) estimates that in Switzerland 22,000 - 29,000 people are living with HIV/AIDS.This results in a prevalence of 2.7 - 3.6 per 1000 people. However, the prevalence of the BAG stands in contrast to calculations of the Swiss HIV Cohort Study (SHCS) which estimates the number of HIV infected individuals living in Switzerland of about 15'000-20'000 (Kohler et al, AIDS, 2015).
There are no symptoms or signs that might diagnose or exclude a HIV infection for sure. Persons who become newly infected with HIV present symptomatically in approximately two third of cases with an acute retroviral syndrome, which is commonly described as flu-like syndrome and varies with regard to intensity and duration (see also the
acute HIV infection. Since the symptoms of a HIV infection can be very unspecific both in the acute and in the chronic phase and the acute HIV infection may present with atypical or unexpected symptoms in up to one third of cases, the diagnosis is often missed early on after infection. It is therefore essential to think even in the absence of a classical acute retroviral syndrome or atypical symptoms of a HIV infection, in particular when the history (e.g., previous sexual risk contacts) or belonging to a risk group (e.g., men who have sex with men, multiple sexual partners) are indicative. In this case, an HIV test should be made with a low threshold.
For HIV screening combined tests (so called Combo tests) are used which detect both HIV antibody against HIV-1 and HIV-2, and HIV-1 p24 antigen. In half of newly infected patients the combined tests become reactive within about 16 days after infection. However, in the other half it may takes longer. Therefore, it is still considered that HIV infection can only be ruled out by a negative HIV test three months after exposure to HIV. In extremely anxious people and in people who demonstrably had sexual contact with untreated HIV-infected individuals, an HIV test can at best make sense four to six weeks after risk contact. However, a negative test is not conclusive at this time to prove the status of "HIV-negative". A final test is absolutely indicated three months after potential risk situations. Combo tests are also available as rapid tests for walk-in clinics and STI clinics. However, the sensitivity of rapid tests is significantly less than the sensitivity of the laboratory tests in patients with acute HIV infection and therefore is not recommended for this situation.
The success of antiretroviral therapy to HIV-1 is unique in the modern medicine history. A previously almost 100% fatal disease could be turned into a chronic treatable disease. If nowadays antiretroviral therapy is started early according to international recommendations, the negative effects of HIV-1 on the human organism can be minimized. This results in otherwise healthy HIV-infected people in an almost normal life expectancy. In addition, patients with successful treatment are no longer infectious, which is crucial for curbing the pandemic. The International Antiviral Society-USA (IAS-USA) recommends in its the latest version of Guidelines that antiretroviral therapy (ART) should be offered to all HIV-infected patients, regardless of their CD4 cell counts. This recommendation is based on the results of data from cohort studies, which showed that the benefit of treatment clearly overweigh the risks today. Other guideline panels such as the WHO and the DHHS have also adapted this strategy in particular after the START trial was published in 2015. Since ART is also a highly effective element of prevention, it makes sense to treat as many patients as possible. For the prevention of drug resistance and improvement of effectiveness ART is mostly prescribed as a combination of different classes of substances. Which combination is used is a complex decision that must be based on the treatment history of the patient, resistance testing, side effect profile, comorbidities, and drug interactions.