The course of HIV infection differs from person to person. The following phases may occur during the natural course of the infection.
Long-term non-progression due to an effective spontaneous control of HIV by the body can be expected in less than 5% of all HIV-positive individuals. However, antiretroviral therapy can prevent the progression of HIV infection and reverse immuno-deficiency in all patients.
On the following pages you can find the features that characterize these stages.
In this early phase the immune system reacts to the rapidly reproductive virus and reacts to it with the cellular immune system and the production of antibodies. The antibodies become detectable by HIV tests after 2 weeks, but in some cases it may take up to 6 months after the infection.
Symptoms such as flu-like symptoms can appear in about 50% of cases after infection. Examples of possible symptoms are
These symptoms disappear after about 1–4 weeks.
The immune system is able to compensate the loss of immune cells during this period.
Without an antiretroviral treatment this asymptomatic period will last about 5-10 years and depends on the capability of the immune system to combat the virus.
During this period the persons infected with HIV hardly notice that they are infected with HIV. Swelling of lymph nodes may be the only symptom.
In the symptomatic stage constitutional symptoms occur because the immune system is already considerably impaired.
Typical symptoms can be
However, the symptomatic stage is still free of opportunistic infections.
The immune system including the T-helper cells (CD4-positive cells) is so severely reduced that there is no adequate protection against numerous infections. This is the full-blown stage of immunodeficiency called AIDS.
The following opportunistic infections (OI) can occur:
These diseases usually appear when the number of helper cells is less than 200/ul. Without treatment these conditions are life-threatening.
Since the introduction of highly active antiretroviral therapy (HAART) the incidence of opportunistic infections has been drastically reduced. If the helper cell count is low despite therapy or because HAART has not yet been started a prophylactic therapy for opportunistic infections should be added (e.g.Pneumocystis prophylaxis or antimycobacterial prophylaxis).
Most opportunistic infections can be targeted by drugs. However, the key to successful management of opportunistic infections is the reversion of the underlying immunodeficiency by antiretroviral therapy.