What is HIV?

HIV stands for human immunodeficiency virus.
Human means that HIV infection is a condition that affects humans. While there are similar viruses in some animals (e.g. cats, monkeys), HIV is only found in people.

A virus is a living microscopic organism that needs to live in cells of another life form (host cells) in order to reproduce itself. Most viruses are normally counteracted by the immune system and immunity to them is developed. HIV, however, is a virus that lives and multiplies within immune cells, thus destroying them and weakening the immune system.

Immunodeficiency means a weak immune system. That is, the body’s ability to fight off infection and disease is much weaker than normal. By destroying immune cells, HIV is constantly weakening the immune system, thus making the body vulnerable to a range of other diseases and infections.

What is AIDS?

AIDS stands for Acquired Immune Deficiency Syndrome.

Acquired means that people are not born with AIDS. It is not a genetic condition. A newly born baby might be born carrying HIV, but will not be born with AIDS.

Immune deficiency (immunodeficiency) means a weak immune system. That is, the body’s ability to fight off infection and disease is much weaker than normal. By destroying immune cells, HIV is constantly weakening the immune system, thus making the body vulnerable to a range of other diseases and infections.

A syndrome may be described as a collection of symptoms or illnesses that occur together as the direct result of a particular cause. In the case of AIDS, the cause is HIV. During advanced stages of HIV infection a person may develop a range of illnesses and conditions typical of Acquired Immune Deficiency Syndrome (AIDS).

Is there a difference between HIV and AIDS?

Yes. If you have HIV (are HIV positive), this does not necessarily mean you have AIDS. A person with HIV is not considered to have AIDS until they are diagnosed with one or more of the ‘AIDS-defining conditions’ (see What happens after a person is infected with HIV). It is possible to have HIV for many years without having any of the symptoms or signs that define AIDS. There are many more people with HIV infection than there are people with AIDS.

How do you get HIV?

Three bodily fluids contain HIV in a high enough concentration for it to be passed on if even a small amount of one of them enters the bloodstream. These fluids are blood, semen (including pre-cum) and vaginal fluids. Blood, semen or vaginal fluids containing HIV may enter a person’s bloodstream in the following ways:

• Unprotected vaginal or anal intercourse (‘unsafe sex’)

During unprotected vaginal and anal intercourse tiny unnoticeable cuts or abrasions in the vagina, anus or penis can allow infected blood, semen or vaginal fluids to enter the bloodstream.

‘Unprotected’ means without the use of a condom and lubricant. To be used properly, a condom needs to be put on and taken off correctly. Lubricant should always be used and it must be a water-based lubricant such as KY Jelly, Wetsuff or Lubafax. Oil-based lubricants, such as baby oil or Vaseline, may damage the condom and allow bodily fluids to be exchanged.

• Blood contact between an HIV-positive and an HIV-negative person

A highly effective method of passing blood from an infected person directly into the bloodstream of another person is through sharing syringes or needles (or other injecting equipment). After injecting drugs there is often blood left on the needle or in the syringe. If another person uses this injecting equipment, they may be exposed to blood containing HIV.

Using any other equipment that is not sterile to puncture the skin can also pass on HIV. This includes equipment used for body and ear piercing, tattooing, and some medical and dental procedures.

Blood contact can also occur during an accident such as a needlestick injury. However, if proper infection control procedures are used the chances of infection are extremely small (see What should I do if there is an accident involving blood).

• During pregnancy, birth or breastfeeding

If a woman who is HIV-positive becomes pregnant, there is about a 20-30% chance that the baby will also become HIV-positive. This may happen:

1. during pregnancy, by infected blood passing through the placenta into the baby’s bloodstream
   
   
2. during the birth itself, whether vaginal or caesarean delivery
   
   
3. during breastfeeding (Note: Breast milk is not a risk for older babies, children or adults, who all have well developed stomach acids that kill HIV. A newly born baby, however, may not have sufficient quantities of these so may become infected)
   

However, treatment of the mother with anti-retroviral drugs decreases the risk of mother to child transmission to around 1-2%. It is important that HIV positive women who become pregnant seek medical care to reduce the risk of transmission to their child.

Who is at risk of HIV infection?

• anyone who has unsafe sex with a person whose HIV status is positive or unknown
  
  
• anyone whose blood comes into contact with the blood of a person whose HIV status is positive or unknown, for example when sharing syringes and needles
  
  
• the baby of an HIV-positive mother (during pregnancy, birth or breastfeeding)
  
  
  

How can I avoid getting HIV?

• use a condom and water-based lubricant when having sex with a person whose HIV status is positive or unknown
  
  
• use a clean syringe and needle when injecting drugs
  
  
• make sure that equipment is sterile if getting a piercing or tattoo