Updated 04 January 2018

Progression of HIV/Aids

The disease is best understood as a continuum from initial infection to terminal illness.


Although HIV infection can theoretically be divided into four different phases, these phases are not, in practice, as distinct. If you’re HIV positive, your health will depend on how strong your immune system is, your CD4 cell count and viral load, and on whether you’ve been exposed to other infections and diseases.

HIV infection can, however, be divided into the following broad phases or stages:

Stage 1: The primary HIV infection phase

The acute phase of HIV infection (also called acute seroconversion illness) begins as soon as seroconversion has taken place. Seroconversion is when your HIV status converts or changes from being HIV-negative to HIV-positive. Prior to seroconversion, an HIV test would be negative. Following seroconversion, the HIV test would show that you’re HIV-positive.  

The time between the onset of HIV infection and the appearance of detectable antibodies is known as the ‘window period’. This period lasts for a couple of weeks. During this time, an HIV test would show that a person is HIV-negative even though they’ve been infected with the virus. This is why a follow-up HIV test is always recommended if you have a negative HIV test.

About 30% - 60% of HIV-infected people develop ‘flu-like symptoms such as a sore throat, headache, mild fever, fatigue, muscle and joint pains, swelling of the lymph nodes, rash and (occasionally) oral ulcers. These symptoms usually last for a week or two.

Because the virus replicates rapidly, the viral load is usually very high during this acute phase.

Stage 2: The asymptomatic latent phase

The second phase of HIV infection is the asymptomatic latent or silent phase. During this stage, an infected person displays no (or very few) symptoms. During this phase, many HIV-positive people are unaware of the fact that they’re carrying the virus – unless they’ve had an HIV test and know their status. This means that they can unwittingly infect new sexual partners.

If you’re HIV-positive and in this second, latent phase, the virus is still active in your body. Over time, however, the virus will start to destroy your immune system. The good news is that most people (especially those who are on ART) remain HIV-positive for many years without any manifestation of clinical disease.

Stage 3: The minor symptomatic phase of HIV disease

In the third phase of infection, minor and early symptoms usually start to appear. At this stage, your viral load is increasing, your immune system begins to fail, and opportunistic infections occur.

If you’re in this phase, you may experience:

  • Mild to moderate swelling of the lymph nodes in the neck, armpits and groin
  • Occasional fevers
  • Oral candidiasis (thrush)
  • Pulmonary tuberculosis
  • Oral hairy leukoplakia (causing white patches on the tongue)
  • Shingles (or herpes zoster)
  • Skin rashes and nail infections
  • Sores in the mouth that come and go
  • Recurrent upper respiratory tract infections
  • Weight loss of up to 10% of your usual body weight
  • General feelings of tiredness and not feeling well

Stage 4: AIDS

The fourth stage is known as Acquired Immunodeficiency Syndrome (AIDS).
 Major symptoms and opportunistic diseases begin to appear as your immune system continues to deteriorate and the viral load gets higher. At this point, your CD4 count drops significantly (below 200) and your viral load becomes very high (between 100,000 and 1 million).

The following symptoms usually indicate advanced immune deficiency:

  • Oral and vaginal thrush infections (thrush) that are persistent and recurrent
  • Oesophageal candida (thrush in the food pipe)
  • Extra-pulmonary tuberculosis (TB) that affects other parts of the body besides the lungs
  • Recurrent herpes infections such as cold sores (herpes simplex)
  • Recurrent herpes zoster (or shingles)
  • Bacterial skin infections and skin rashes
  • Bacterial pneumonia
  • Kaposi’s sarcoma, a form of skin cancer
  • Pneumocystis jerovici pneumonia (PJP) – the most common opportunistic infection in people with HIV
  • Fever for more than a month
  • Persistent diarrhoea for more than a month, leading to wasting syndromeWeight loss of more than 10% of usual body weight
  • Generalised lymphadenopathy, a disease affecting the lymph nodes (or, in some cases, the shrinking of previously enlarged lymph nodes)
  • Toxoplasmosis of the brain (an infection caused by a common parasite)
  • Cytomegalovirus (a common herpes virus)
  • Cryptococcal meningitis (an infection of the tissues covering the brain and spinal cord)
  • Peripheral neuropathy (damage to the nerves in the hands and feet)
  • Abdominal discomfort
  • Headache
  • Oral hairy leucoplakia (white patches on the tongue)
  • Persistent cough and reactivation of tuberculosis

HIV: What the CD4 and viral load numbers mean 

The CD4 count

CD4 cells are white blood cells that fight viral and bacterial infections. They’re also known as T-cells, or T helper cells. HIV targets and infiltrates the CD4 cells in the human body, tricking the cells into making more copies of HIV. It’s this mechanism that makes HIV such a tricky virus to control.

Your CD4 count is indicated in cells per cubic millilitre and is measured by taking a blood sample. A normal CD4 count is between 800 and 1,500 mm3, although it varies between individuals. If your CD4 count is decreasing, it means that your immune system is becoming less effective at fighting off infections.

CD4 cell counts are the best predictors of the risk of opportunistic diseases in people with HIV/AIDS. A CD4 count below 500 cells per mm3 usually indicates immune suppression and vulnerability to opportunistic infections. Once your CD4 count drops below 350 cells per mm3 of blood, you need to be assessed for antiretroviral treatment (ART).

Here is a quick guide to CD4 counts:

  • Between 500 and 1200 = normal for people who don’t have HIV
  • Above 350 = HIV treatment isn’t usually recommended
  • Below 350 = HIV treatment is recommended
  • Below 200 = There’s a higher risk of illnesses and infections, so HIV treatment is recommended

Note that your doctor may give your CD4 results as a percentage:

  • Above 29% = similar to a CD4 count of above 500
  • Below 14% = similar to a CD4 count of below 200

What is ‘viral load’?

The CD4 count is one measure of HIV progression; the other is viral load. This refers to the amount or concentration of virus in the blood and is an indication of how sick an HIV-infected person is. The higher the viral load, the more progressive the HIV disease. 

If you’ve recently been infected with HIV, your viral load is likely to be high. This will decrease over time, as your treatment kicks in.

The viral load can be “counted” by doing a blood test such as the Polymerase Chain Reaction (PCR) test, which measures the number of HIV copies in your blood. The bDNA (branched DNA) and NASBA (nucleic acid sequence based amplification) methods are also used to test viral load. The result is expressed as the number of copies of HIV per millilitre of blood.

If you’re on antiretroviral treatment (ART), your viral load should be lower than detectable limits. If the viral load is detectable, it means that the treatment isn’t working well enough. This could either be because of non-compliance (i.e. you’re not taking your medication exactly as prescribed) or because the virus has developed resistance to the drugs.

Here’s a quick guide to viral load count:

  • Between 100,000 and 1 million copies = high
  • Less than 500 copies = low
  • Below 50 copies = “undetectable” (i.e. the virus is still present, but your treatment is successfully controlling it)

Note that tests made by different manufacturers might give slightly different results, which is why your doctor or clinic nurse should use the same type of test every time.

The ‘dance’ between viral load, CD4 count and disease progression

Disease progression, or the extent to which an HIV-infected person gets sick with opportunistic diseases and infections, will depend on the viral load as well as the CD4 cell count. The higher the viral load, the lower the CD4 cell count – and the higher the risk of infections.

Opportunistic infections associated with advanced disease are more likely to occur once your CD4 count falls below 350. The types and numbers of infections may also increase as your CD4 count drops to below 200. This is known as the AIDS phase, and the viral load now starts to climb to significantly higher levels. The progression to the final phase of AIDS (and death) will be much faster.

Conversely, a lower viral load goes hand in hand with a higher CD4 cell count, because fewer viruses in the blood give the immune system a chance to build up its resources again. If you are HIV-positive and have a low viral load and a high CD4 count, you can remain healthy for years because your

 immune system is strong enough to fight off infections.

If you’re HIV-positive, it’s important to get your CD4 and viral load tests done regularly. These results will give you essential information about the effect HIV is having on your body. The aim of HIV treatment is to have a very low or undetectable viral load and a high CD4 count.

The Universal Test and Treat (UTT) policy

Previously in South Africa, treatment started when your CD4 count dropped to 200 or less or when certain opportunistic infections became evident – whichever came first.

The CD4 count for treatment eligibility was later changed to 350. Then, in September 2016, a universal test and treat (UTT) policy for all HIV-positive people was introduced.

This means that all HIV-positive children, adolescents and adults, regardless of CD4 count, are offered ART, prioritising those with a CD4 count of 350 or less. Once treatment is started, there’s normally an increase in CD4 count and a corresponding decrease in viral load.


Read Health24’s Comments Policy

Comment on this story
Comments have been closed for this article.

Ask the Expert

HIV/Aids expert

Dr Sindisiwe van Zyl qualified at the University of Pretoria in 2005. She is a patients' rights activist and loves using social media to teach about HIV. She is in private practice in Johannesburg.

Still have a question?

Get free advice from our panel of experts

The information provided does not constitute a diagnosis of your condition. You should consult a medical practitioner or other appropriate health care professional for a physical exmanication, diagnosis and formal advice. Health24 and the expert accept no responsibility or liability for any damage or personal harm you may suffer resulting from making use of this content.

* You must accept our condition

Forum Rules