What is HIV?

Acquired immune deficiency syndrome (AIDS) is not a single disease.

It is a diagnosis that results from a spectrum of conditions that can occur when a person’s immune system is seriously damaged after years of attack by HIV. The terms HIV and AIDS are not interchangeable, but it is possible to move in and out of an AIDS diagnosis. It is important to remember that a person who is infected with HIV does not necessarily have AIDS. However, all people with AIDS have HIV.

HIV damages the body’s immune system and renders the body vulnerable to other diseases and infections – its symptoms are most commonly similar to those of any chronic viral infection. During advanced stages of HIV infection, a person may develop any of a number of opportunistic infections considered to be AIDS defining illnesses.

Despite advances made over the course of the epidemic HIV and AIDS are still here and there is no cure or vaccine.

HIV is detected by an HIV antibody test. It is incorrect to call it an ‘AIDS test’ because the test cannot detect AIDS, but instead detects the antibodies that are produced as a result of HIV infection. It can take up to 12 weeks for someone’s immune system to produce antibodies to HIV. This is called the ‘window period’. An HIV antibody test performed during this window period could be negative even though the person may be HIV-positive. There are now special blood tests (nucleic acid amplification) which can detect HIV infection during the window period.

A person who has a positive HIV antibody test can be referred to as being ‘HIV-positive’.

The ability of HIV to live outside the body is very limited and therefore HIV is not particularly easy to transmit. It is a communicable disease, but it is not contagious like air-borne viruses such as influenza. HIV cannot be transmitted by hugging, shaking hands, coughing or sneezing. Nor can it be transmitted by sharing glasses, cups or utensils. There are three main modes of HIV transmission:

• Condomless anal and vaginal sexual intercourse
• Sharing drug injecting or tattooing equipment
• Mother to child during pregnancy, birth or breast feeding

See our HIV Transmission page for more details.

Viral load refers to the amount of HIV circulating in the blood. To find out a person’s viral load, a doctor takes a sample of blood and sends it to a laboratory where a viral load test is conducted.

When the result comes back, viral load is indicated as a number. The number indicates the amount of viral copies per millilitre of blood (written as copies/ml). Viral load can range from below 20 to over one million copies/ml. In layman’s terms, viral load refers to the amount of virus that is in the HIV-positive persons’ body.

An undetectable viral load level is when the level of the virus in the body is reduced to a point that it cannot be detected by current tests. This does not mean that their body is free or cured of HIV, only that there is less than the test can detect.

In fact, all HIV positive people with an undetectable viral load still have HIV in their blood, as well as in blood cells, tissue and other bodily fluids. HIV-positive people on sustained anti-HIV treatment regimes are commonly able to maintain their viral load at low or undetectable levels.

However, someone living with HIV with a sustained undetectable viral load CANNOT pass on HIV to their sexual partners.

Victoria has the second largest epidemic in Australia, behind New South Wales. In terms of transmission, HIV has largely been contained to very low rates amongst injecting drug users, sex workers and those who receive blood transfusions. Sexual transmissions amongst men who have sex with men account for the majority of infections, but transmission through heterosexual sex is slowly increasing.

Annual rates of new HIV infections in Victoria dropped from a peak in 1985 (over 500 cases) to a low in 1999 (141 cases). Since then the rate has climbed and evened out to roughly between 280-320 cases over the past three years (2013-2015). AIDS Diagnoses peaked from 1992 to 1995 (180 cases) and has evened out to roughly between 40-50 cases over the past three years (2013-2015).

HIV and AIDS are notifiable illnesses which means that the Department of Health and Human Services (DHHS) is notified when a new notification identified. Statistics on HIV and AIDS in Victoria are available from the DHHS.

In Australia, the number of notifications has remained relatively stable over the past four years (2012-2015) with between 1,000 to 1,080 new notifications recorded nationally. Similar to the Victorian epidemic, men who have sex with men make up the majority of these new notifications, however this changes when you look at each state or territory separately. For example, in Western Australia, the proportion is roughly 50% heterosexual and 50% male to male sex.

In relation to the diagnoses of AIDS in Australia, the pattern is similar to that of Victoria. For example, peaking around 1987 then slowly dropping to their lowest point around 1999. The latest reports on HIV in Australia can be found at The Kirby Institute.

The size and nature of the epidemic varies greatly from country to country. In many western countries, condomless anal sex remains the main risk category. However, in sub-Saharan Africa heterosexual vaginal sex remains the largest risk category and amongst some South-Eastern Asian countries injecting drug use is the main risk factor. Furthermore AIDS diagnosis rates also vary, depending on the availability of treatment and other factors such as stigma and financial costs. Lastly, not all countries have good reporting systems so the data may not be accurate. Statistics are available from UNAIDS.