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How HIV infects the body

HIV is a virus that can cause an HIV infection if it gets into our blood stream.  

It then goes on to infect our immune system – the part of our body that keeps you healthy. 

It does this by entering T-helper cells (also called CD4 cells) so that our immune system can’t find and destroy it. Then it makes copies of itself so it can go on to infect other cells. 

This is called the HIV lifecycle and it is how the virus multiplies in our body. 

Taking antiretroviral drugs (ARVs) is the only way to interrupt the HIV lifecycle and stay healthy. 

How does HIV get into the body?

HIV can get into our body when certain body fluids of a person with HIV are able to get into our blood stream. This can happen through: 

  • unprotected sex (without a condom)  

  • sharing needles or syringes  

  • pregnancy, birth or breastfeeding.  

How do you get HIV?

What part of the body does HIV infect?

HIV infects our immune system. This is the part of our body that stops us getting sick. HIV infects a type of white blood cell in our immune system called a T-helper cell (also called a CD4 cell). These cells keep us healthy by fighting off infections and diseases. However, HIV hides inside these cells, tricking the body so that the immune system can’t find and destroy it. 

How does HIV spread throughout the body?

HIV cannot reproduce on its own, so it must get into these cells so that it can copy itself.  

First, the virus attaches itself to a T-helper cell and fuses with it (joins together). It then takes control of the cell’s DNA, makes copies of itself inside the cell, and finally releases more HIV into the blood.  

HIV will continue to multiply and spread throughout the body. This is a process called the HIV lifecycle. 

What impact does HIV have on the body?

HIV weakens the body’s natural defences, and over time it damages the immune system.  

The impact of HIV on the body depends on a person’s general health, such as: 

  • how quickly they are diagnosed  

  • how quickly they start antiretroviral treatment 

  • how consistently they take their treatment 

  • how well they keep themselves healthy.

Some people will have symptoms and some people won’t. 

How does treatment stop HIV progressing into AIDS? 

Antiretroviral treatment for HIV includes several different types of drugs (ARVs). Each drug targets a different stage in the HIV lifecycle. This means that HIV is stopped in multiple ways. 

If taken correctly, treatment keeps the immune system healthy and stops illnesses. 

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What are the different stages in the HIV lifecycle?

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The HIV lifecycle is made up of four stages. Each of these involve a number of processes which happen in and around a human CD4 cell. 

What happens at the binding and fusion stage? 

HIV attaches to a T-helper cell. It then fuses to it and releases its genetic information into the cell. 

The types of ARVs that stop this stage of the lifecycle are called fusion or entry inhibitor drugs. They stop HIV from entering the cell. Your healthcare provider will let you know if these are the right ARVs for you. 

What happens at the reverse transcription (conversion) and integration stage? 

Once inside the T-helper cell, HIV converts its genetic material into HIV DNA, a process called reverse transcription. The new HIV DNA then enters the nucleus of the host cell and takes control of it. 

The types of ARVs that stop this stage of the lifecycle are called: 

  • NRTIs (nucleoside reverse transcriptase inhibitors) 

  • NNRTIs (non-nucleoside reverse transcriptase inhibitors) 

  • Integrase inhibitor drugs. 

Your healthcare provider will let you know if these are the right ARVs for you. 

What happens at the transcription and translation (replication) stage? 

The infected T-helper cell then produces HIV proteins. These help make more HIV particles inside the cell. 

What happens at the assembly, budding and maturation stage? 

The new HIV is put together and then released from the T-helper cell into the bloodstream to infect other cells. Then the process begins again. 

The type of drugs that stop this stage of the lifecycle are called protease inhibitor (PI) drugs. Your healthcare provider will let you know if these are the right ARVs for you. 

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  • Last updated: 31 March 2022
  • Last full review: 01 March 2022
  • Next full review: 01 March 2025
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