Human immunodeficiency virus (HIV) infection - including symptoms, treatment and prevention

Without treatment, human immunodeficiency virus (HIV) infection will usually result in acquired immune deficiency syndrome (AIDS). However, HIV antiretroviral therapies introduced in the mid-1990s, which are available to all people living in Australia who are HIV positive, have resulted in the virtual elimination of AIDS in Australia.

HIV in Australia is now considered a manageable condition. Whilst a vaccine or cure is yet to be found, with treatment most people living with HIV in Australia can achieve an undetectable viral load, meaning they are not at risk of transmitting HIV to their sexual partners and will live long and healthy lives providing they take their treatment as prescribed.

Human immunodeficiency virus is a notifiable condition1

How HIV is spread

HIV infection occurs when certain body fluids (blood, semen, vaginal fluid and breast milk) containing the virus come into contact with another person’s tissues beneath the skin’s surface (for example, through needle puncture or broken skin), or mucous membranes (the thin moist lining of many parts of the body such as the nose, mouth, throat and genitals).

In Australia, most HIV infections now result from unprotected sex (anal or vaginal intercourse without a condom) and/or the sharing of injecting equipment (needles and syringes).

If you are pregnant and HIV positive, transmission to your baby may occur if you are not taking treatment for HIV. Therefore, HIV testing is routinely offered amongst other tests in early pregnancy. Taking effective treatment for HIV in pregnancy virtually eliminates the risk of passing HIV onto your baby. 

Routine social or community contact with a person living with HIV carries no risk of infection. There is no evidence of the spread of HIV through social contact in schools, at home or in the workplace. HIV has not been transmitted through:

  • air or water
  • swimming pools or toilets
  • sharing of plates, cups or cutlery
  • kissing
  • coughing
  • sneezing or spitting.

In addition, there is no evidence HIV can be spread by mosquitoes or other biting insects.

In Australia, receiving blood, blood products or an organ transplant is not a risk for HIV infection as screening for HIV occurs.

Signs and symptoms of HIV

Acute infection

A few weeks after infection with HIV, a flu-like illness might develop. This is known as seroconversion illness, which is a sign that the body is reacting to the infection. Symptoms may include:

  • muscle aches
  • low-grade fever
  • headaches
  • sometimes a rash
  • swelling of the lymph glands may also occur.

The symptoms of seroconversion illness can be so mild they go unnoticed, or, in some people, it can be quite severe and last for a few weeks before there is a return to seemingly normal health. Either way, seroconversion illness is so similar to many other viral infections that the diagnosis of HIV infection may not be made at this time. 

It is now recommended that HIV treatment starts as soon as possible after diagnosis. Whilst it is not a cure, treatment is known to stop the disease progression that may otherwise lead to AIDS.

Longer term, untreated HIV infection

The length of time that a person with untreated HIV infection may live without symptoms varies widely, but usually severe disease develops in adults within 10 years of infection.

When symptoms develop in untreated HIV, they may not be specific and can include:

  • chronic loss of appetite
  • diarrhoea
  • weight loss
  • fever
  • lethargy
  • fatigue.

Untreated HIV destroys certain cells within the immune system (CD4+ also called helper T cells) from the time of infection onwards, causing more and more damage. AIDS occurs when the damage to the immune system is so great the body can no longer stop some infections or cancers it normally fights successfully. Infections not usually seen in healthy people (opportunistic infections) and certain unusual tumours such as Kaposi’s sarcoma, might occur. Cancer of the cervix and anal cancer are more common in people with HIV. Vaccination for human papillomavirus (HPV) can help protect against these cancers.

Untreated HIV can also cause infection in the brain, which can lead to nervous system disorders or dementia in some people with HIV infection.

Diagnosis of HIV

Diagnosis of HIV infection is made using blood tests. A positive blood test indicates the development of antibodies to HIV and therefore the presence of the virus. Antibodies to HIV usually develop within a few weeks to three months. Even though the blood test for antibodies may not be positive during the early stage of infection (the window period), the virus will be present in certain body fluids (blood, semen, vaginal fluid and breast milk), making the person infectious to other people. 

A blood test, where a sample of blood is taken from a vein in your arm, to diagnose HIV infection can be ordered by a general practitioner (GP) or conducted at a sexual health clinic, such as:

SHINE SA also offers HIV point of care testing at their Rapido Clinic.

Incubation period

(time between becoming infected and developing symptoms)

While illness may not occur for months or years after becoming infected with HIV, without treatment, most adults will develop severe disease within 10 years of infection.

Infectious period

(time during which an infected person can infect others)

Once a person has been infected with HIV, they remain infected for life and may be able to transmit the virus to others. The risk of transmitting the infection to another person is dependent on the level of virus (viral load) in the body fluids (blood, semen, vaginal fluid and breast milk) of the infected person. 

The risk of transmitting the virus to others is higher when the viral load is higher, in particular, in early infection (when a person may not be aware they have HIV) and late in untreated infection (when the immune system is failing). Research demonstrates that having a consistently low (undetectable) viral load, which can be achieved by taking daily HIV treatment, dramatically reduces infectiousness and lowers the risk of HIV transmission through sex to zero. The risk of transmission through injecting or breast feeding is also dramatically reduced, however more research is needed before it can be said the risk is zero. Certain factors, including not taking daily treatment may increase the risk of transmission. The risk of HIV can be significantly reduced by pre-exposure prophylaxis (PrEP) for HIV, post-exposure prophylaxis (PEP) for HIV, consistent condom use and/or safe injecting practices.

Treatment for HIV

Although there is no cure for, or vaccine against, HIV infection, significant advances in HIV treatment have been made over recent years that are known to slow or even stop the disease progression that would otherwise have led to AIDS. This means HIV is no longer a terminal illness and is now considered a manageable health condition. 

Multiple treatment options are available for people living with HIV. Treatments vary from person to person depending on disease progression, drug resistance and other health conditions. For most people, treatment is as simple as taking a single pill everyday with little to no side-effects experienced. 

The majority of people on effective HIV treatment in countries like Australia will achieve long-term suppression of symptoms and an undetectable viral load, meaning they can live a long and healthy life without the risk of transmitting HIV to their sexual partners. 

Regular measurement of the HIV viral load and the levels of CD4+ cells assist in indicating the effectiveness of treatments. It is recommended that a sexual health physician, infectious diseases specialist or general practitioner with expertise in HIV medicine undertake these assessments. 

When HIV infection is diagnosed late or when an individual is unable to take treatment as prescribed, the untreated infection will likely cause immune system destruction, secondary infections (opportunistic infections) and certain cancers. Using other antiviral drugs and antibiotics to prevent secondary infection may prevent severe illness and premature (early) death.

HIV treatment for people who are not eligible for Medicare

From 2023 onwards, the Australian Government will be partnering with State and Territory Governments to simplify and improve access to HIV treatment for people who live in Australia but are not eligible for Medicare.

Medicare ineligible people living with HIV are advised to speak to their current treating clinician about accessing HIV medications under this program.

Medicines for the treatment of HIV that are dispensed through SA Health pharmacies are free (no co-payment) for Medicare ineligible people living with HIV who are accessing care in South Australia.

Further information about the program is available on the ASHM Access to HIV treatment for people without Medicare webpage.

Prevention of HIV

Exclusion from childcare, preschool, school and work is not necessary. Children living with HIV may be advised to stay away from school during outbreaks of infectious disease (for example, chickenpox) to prevent them getting the infection. 

Health Care Workers living with HIV must comply with the requirements of their professional boards and in doing so are usually able to continue working.

HIV infection can be prevented by:

  • Using condoms and water based lubricants for penetrative sex. These reduce the risk of getting HIV, as well as other STI. Having any STI increases the risk of getting an HIV infection.
  • The effective use of pre-exposure prophylaxis (PrEP) – see below
  • Utilising treatment as prevention (TasP). When people with HIV effectively adhere to their treatment regimen their viral load is suppressed to undetectable levels and is sexually untransmittible and the risk of transmission via injecting and breast feeding is dramatically reduced.
  • Not sharing any injecting equipment (including needles, syringes, filters, spoons, swabs and tourniquets).
  • Safely disposing of found or used needles and syringes in a sharp safe, or other sealable and puncture-proof container.
  • Always using standard precautions when handling blood and other body fluids. This will minimise and generally eliminate the risk of transmission of HIV.
  • Covering any open sores, cuts or abrasions with waterproof dressings.
  • Understanding the risk of body tattooing or any body piercing. The risk of being infected with HIV through these practices is lower than for hepatitis B or hepatitis C, but there is still a risk if there is use of unsterile equipment or re-used dyes.

Prevention of transmission to babies

The administration of HIV treatment, if a person is HIV-positive during pregnancy, labour and after delivery, as well as to the newborn baby, reduces the risk of HIV transmission to the baby.

Pre-exposure prophylaxis for HIV

Pre-exposure prophylaxis (PrEP) is the use of antiretroviral medications by HIV negative people who are at medium to high-risk of acquiring HIV, to prevent HIV transmission.

For more information, see: HIV pre-exposure prophylaxis.

Post-exposure prophylaxis for HIV

Post exposure prophylaxis (PEP) for HIV is a four week treatment that may prevent you from becoming infected if you have been exposed to HIV.

PEP needs to begin as soon as possible, within 72 hours after exposure, to be effective.

For more information, see: HIV post exposure prophylaxis.

Useful links


1 – In South Australia the law requires doctors and laboratories to report some infections or diseases to SA Health. These infections or diseases are commonly referred to as 'notifiable conditions'.

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