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signs and transmission

HIV is an acquired viral infection that weakens the immune system. The virus destroys the helper cells of the immune system so that it can no longer perform its task properly, making it easy for pathogens to penetrate the body and damage it, for example. This initially manifests itself in flu-like symptoms, and later in weight loss or pneumonia. AIDS is the final stage of the infection. Find out which other symptoms are typical of HIV and how the virus is transmitted and treated.


HIV (the human immunodeficiency virus) is a virus that causes immunodeficiency. The virus attacks the cells of the immune system (T-helper cells), rendering them unable to perform their function of fighting pathogens such as bacteria and eliminating abnormal cells. As a result, the risk of infections and other diseases, such as cancer, increases. Acquired immunodeficiency syndrome (AIDS) is the term for the final phase of HIV disease when the immune system’s ability to defend the body falls below a certain threshold, leading to the development of sometimes life-threatening diseases. If it is not treated, HIV infection is always fatal.

Different indicators occur depending on the stage of the disease. At first, HIV does not cause any symptoms. It is only after two to six weeks that symptoms similar to those of a cold or flu appear. As a result, HIV infection often goes unnoticed at first, especially because these symptoms subside after a few weeks.

The first signs are:

  • Fever
  • Sore throat, headache, achy limbs
  • Swollen lymph glands in the neck area, swollen tonsils
  • Tiredness/fatigue
  • Night sweats
  • Skin rash with small, red pustules, predominantly on the chest and back

As the immune system continues to weaken, the susceptibility to certain diseases increases. The following symptoms may occur:

  • Fever of over 38.5 degrees
  • Nerve disorders with feelings of numbness, tingling of the limbs, muscle weakness
  • Diarrhoea that lasts for several weeks
  • Shingles
  • Fungal infections in the mouth and genital area

If you have these symptoms, it is important to take an HIV test as soon as possible.

The infectious diseases characteristic of AIDS (AIDS-defining illnesses) appear after an average of seven to twelve years (sometimes even after 20 years). The immune system is already severely damaged at this point and the number of helper cells has dropped below a defined threshold.

In addition to the aforementioned illnesses, the following are typical of AIDS:

  • Bacterial pneumonia
  • Infections with rare pathogens (toxoplasmosis, cryptococcus)
  • Various cancers, such as Kaposi’s sarcoma (a type of skin cancer)
  • Inflammation of the brain and even dementia
  • Chronic herpes virus infections
  • Wasting syndrome: fever and tiredness, severe weight loss, long-lasting diarrhoea (over 30 days)

AIDS can be traced back to an HIV infection. The outer layer of the HIV virus consists of a protein shell that can easily adhere to human cells due to its special surface (lock and key principle). This predominantly affects T helper cells, which are destroyed by the virus together with other immune defence cells. As a result, the immune system is weakened and otherwise harmless pathogens can enter the body more easily and cause infections. Organs may also be damaged by the virus.

HIV is relatively difficult to catch. The virus cannot be transmitted via everyday activities. Infection is only possible if a sufficient quantity of the virus enters the body. This mainly happens during sex or drug use. There are effective means of protection against transmission.
HIV can also be transmitted via the blood, such as via blood reserves during a transfusion (there is no risk of this occurring in Switzerland as blood reserves are tested). It is not possible to catch HIV via droplet infection (e.g. coughing or sneezing).

HIV is most commonly transmitted through unprotected vaginal or anal sex. Condoms, femidoms and pre-exposure prophylaxis (PrEP) offer protection. An injury to the mucous membrane or a venereal disease (e.g. syphilis or gonorrhoea) increases the risk. With successful HIV treatment, the virus is no longer detectable in the blood. HIV cannot then be transmitted even during sex.

Drug addicts can also become infected via contaminated syringes and needles while consuming drugs. Pregnant women can transmit HIV to their baby during childbirth or subsequently during breastfeeding, but there are now good ways to prevent this.

If you suspect that you are infected with HIV, you should first go to your family doctor. If necessary, they can then refer you to an HIV expert (infectiologist). During the medical history interview, you will be asked questions about your lifestyle, e.g. engaging in unprotected sexual intercourse or injection drug use, and possible symptoms. This is followed by a physical examination during which lymph nodes are scanned for swelling.

The exam also determines whether you have a rash. This is followed by a blood test for HIV. For this, blood is usually taken from a vein in the arm and tested in the laboratory. However, there is also a rapid test in which the blood is taken from the fingertip. If antibodies are found in the blood, a second test is performed to confirm the result.

HIV and AIDS remain incurable. However, the infection can be treated effectively. Drug-based therapy is primarily concerned with reducing the viral load in the blood to below the detection limit and thus protecting the immune system – the virus does not infect any more cells and the immune system can recover. Not only can early drug-based treatment keep the symptoms at bay; it can also prevent AIDS. People on effective HIV therapy are no longer contagious to their partners.

They can also live largely normal lives with an average life expectancy. Although the medicines have to be taken for life, they stop the disease from progressing and prevent patients from infecting others.

There are several ways to protect yourself against HIV infection. Practising protected sex, i.e. using a condom or a femidom (a special female condom) during vaginal or anal intercourse reduces the risk of transmission. It is also possible to take a special drug in tablet form for prevention, known as pre-exposure prophylaxis (HIV-PrEP). Non-infected individuals may use this method before intimate contact with an HIV-positive person. HIV-positive people should protect their partners from infection via effective HIV therapy – in this case, it is no longer necessary for the HIV-negative partner to take PrEP.

Which option makes the most sense in each individual case is best discussed with an HIV specialist.

Drug users should be careful to use sterile needles and syringes and not to share them with others.

Since medical standards in developing countries are not usually on a level with those of Western industrialised nations, people travelling to such places should avoid medical treatment that might bring them into contact with syringes or blood whenever possible.

Today, the chances of living a normal life with HIV infection are better than ever. Thanks to effective treatment options, patients usually reach an older age and infections can be prevented so that a partnership or pregnancy can be maintained without any problems. Good medical care by a competent HIV expert is essential. You should therefore contact a suitable specialist and follow the recommended therapeutic measures.

A healthy lifestyle with sufficient exercise and a balanced diet with lots of fresh fruit and vegetables is certainly beneficial. Protective vaccinations, such as those for influenza or pneumococci, can also help to ward off serious illnesses.

You can also obtain information on legal and other issues from the Swiss AIDS Federation.

For more information and support services, please visit:

Aids-Hilfe Schweiz

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  • Beise, Uwe und Kronenberg, Andreas. Guideline zu HIV/AIDS Schweiz (Stand: November 2020), unter: Abrufdatum: 25.11.2022)
  • Universitätsspital Zürich. HIV, unter: (Abrufdatum: 25.11.2022)
  • AIDS-Hilfe Schweiz, unter: (Abrufdatum: 25.11.2022)
  • Berufsverband Deutscher Internistinnen und Internisten. Was ist HIV & AIDS?, unter: (Abrufdatum: 25.11.2022)
  • Robert Koch Institut. HIV Infektion/AIDS, unter: (Abrufdatum: 25.11.2022)
  • Bundesamt für Gesundheit BAG. AIDS, unter: (Abrufdatum: 25.11.2022)