Stages of HIV Infection

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Original Editor - Cindy John-Chu

Top Contributors - Cindy John-Chu and Kim Jackson  

Introduction[edit | edit source]

Human Immunodeficiency Virus (HIV) is a virus that attacks the human immune system (especially the CD4 and T cells) and when left untreated, leads to Acquired Immune Deficiency Syndrome (AIDS). Immunosuppression (the reduced ability to fight infections and other diseases) is determined by laboratory measurements of CD4+ T cells and plasma HIV viral load[1]. As at the end of 2020, it was estimated that 37.7 million people are living with HIV, with two thirds of that population in the African region[2].

Modes of Infection/ How does Infection Occur in the Body?[edit | edit source]

Infection occurs when a one comes in contact with body fluids of infected persons.

Stages of HIV Infection[edit | edit source]

The World Health Organisation (WHO) categorises patients with HIV into four clinical stages and this categorisation results from the patient displaying at least one clinical condition in the stage's criteria[3]. The clinical phases seen in the course of the HIV infection is directly linked to the progression of the infection[3]. The four stages include:

Stage One: Patients in this category are usually asymptomatic. Only characterised by flu-like symptoms and CD4 counts stay above 500 cells per microliter.

Stage Two: Also known as a mildly symptomatic stage. It is characterised by an unexplained weight loss of less than 10% of total body weight; recurrent respiratory infections such as: sinusitis, bronchitis, otitis media, and pharyngitis; an array of dermatological conditions including: recurrent oral ulceration, papular pruritus eruptions and fungal nail infections [3].

Stage Three: Also known as the moderately symptomatic stage of the infection. The following characterises this stage: weight loss of greater than 10% of the total body weight, unexplained diarrhoea occurring for more than one month, pulmonary tuberculosis; bacterial infections like: pneumonia, pyelonephritis, empyema, pyomyositis, meningitis and bacteremia; mucocutaneous conditions such as:recurrent oral candida sis, gingivitis or periodontics[3].

Stage Four: At this stage, a clinical diagnosis of Acquired Immune Deficiency Syndrome (AIDS) is made when the following clinical findings are made: HIV wasting syndrome, pneumocystis pneumonia, recurrent severe or radiological bacterial pneumonia, extrapulmonary tuberculosis, HIV encephalopathy, CNS toxoplasmosis, oesophageal candidiasis and Kaposi's sarcoma[3]. CD4 count here drops below 200 cells per microliter.

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References[edit | edit source]

  1. Simon V, Ho DD, Karim QA. HIV/AIDS epidemiology, pathogenesis, prevention, and treatment. The Lancet. 2006 Aug 5;368(9534):489-504.
  2. World Health Organisation. HIV/AIDS. Available from: (Acessed 10 December, 2021).
  3. 3.0 3.1 3.2 3.3 3.4 Weiner JL, Kovarik CL. The WHO Clinical Staging System for HIV/AIDS. Virtual Mentor 2010; 12 (3): 202-206