SIDA & VIH
Can you get AIDS from. . . ?
HIV is a virus that damages human immune cells. It weakens the immune system and leads most people to develop AIDS. Like all viruses, HIV infects the cells of a living organism in order to make copies of itself. HIV can only be transmitted in certain ways and the purpose of this page is to explain how you can and can’t become infected.
For many years now public health campaigns and education programmes have tried to teach people the ways in which they might be at risk of HIV transmission. In spite of this, some people continue to be confused about what is safe and what is not.
This confusion can lead to people becoming unnecessarily worried about ‘catching’ HIV. As a result, they may avoid or reject HIV positive people, increasing prejudice and paranoia about HIV and AIDS, and causing HIV positive people to feel isolated and alone.
Often these fears are unfounded. HIV is a virus that is found in blood and other body fluids such as semen and vaginal fluids. It cannot live for long outside the body, so to be infected with HIV you need to allow some body fluid from an infected person to get inside your body.
The most common ways that people become infected with HIV are:
- having sexual intercourse with an infected partner.
- injecting drugs using a needle or syringe that has been used by someone who is infected.
HIV can be passed on in both these ways because the virus is present in the blood and sexual fluids of an infected person. If infected blood or sexual fluid gets into your bloodstream, then you can become infected.
How HIV is passed on
Vaginal sex
HIV is found in the sexual fluids of an infected person. For a man, this means the pre-come and semen fluids that come out of the penis before and during sex. For a woman, it means HIV is in the vaginal fluids which are produced by the vagina to keep it clean and to help make intercourse easier.
If a man with HIV has vaginal intercourse without a condom then infected fluid can pass into the woman's bloodstream through the vagina. The risk of HIV transmission is increased if the woman has a cut or sore inside or around her vagina; this will make it easier for infected fluid to enter her bloodstream. Such a cut or sore might not always be visible, and could be so small that the woman wouldn't know about it.
If a woman with HIV has sexual intercourse without a condom, HIV could get into the man's blood through a sore patch on his penis or by getting into his urethra (the tube that runs down the penis) or underneath his foreskin (if he has one).
If there is any contact with blood during sex, this increases the risk of infection. For example, there may be blood in the vagina if intercourse occurs during a woman's period.
Oral sex
Oral sex with an infected partner does carry a small risk of HIV infection. If a person gives oral sex (licking or sucking a man’s penis) to a man with HIV, then infected fluid could get into the mouth. If the person has bleeding gums or tiny sores or ulcers somewhere in their mouth, there is a risk of the infected fluid entering their bloodstream.
The same is true if infected sexual fluids from a woman get into the mouth of her partner.
There is also a small risk if a person with HIV gives oral sex when they have bleeding gums or a bleeding wound in their mouth. Saliva does not pose a risk.
HIV infection through oral sex alone seems to be very rare, and there are things you can do to protect yourself. For more information go to our HIV and oral sex page.
Anal sex
If a couple have anal intercourse the risk of infection is greater than with vaginal intercourse. The lining of the anus is more delicate than the lining of the vagina, so it's more likely to be damaged during intercourse and any contact with blood during sex increases the risk of infection.
Injecting drugs
Injecting drug users are one of the most high-risk groups for exposure to HIV. Sharing injecting equipment is a very efficient way to transmit blood-borne viruses such as HIV and Hepatitis C. Sharing needles and “works” (syringes, spoons, filters and water) is thought to be three times more likely to transmit HIV than sexual intercourse. Disinfecting equipment between use can reduce the chance of transmission, but does not eliminate it entirely.
For more information, go to our HIV prevention, harm reduction & injecting drug use page.
Blood transfusions
Some people have been infected through a transfusion of infected blood. These days, in most countries all the blood used for transfusions is tested for HIV. In those countries where the blood has been tested, HIV infection through blood transfusions is now extremely rare.
Blood products
Blood products, such as those used by people with haemophilia, are now heat-treated to make them safe.
Mother to child transmission
An infected pregnant woman can pass the virus on to her unborn baby either before or during birth. HIV can also be passed on during breastfeeding.
If a woman knows that she is infected with HIV, there are drugs that she can take to greatly reduce the chances of her child becoming infected.
For more information, go to our pages about pregnancy and mother-to-child transmission of HIV.
Infection in the health-care settings
Health-care workers on rare occasion have become infected with HIV by being stuck with needles containing HIV-infected blood. A few have also become infected by HIV-infected blood getting into the bloodstream through an open cut or splashes into a mucous membrane (e.g. eyes or the inside of the nose).
There have only been a few documented instances of patients becoming infected by a health-care worker.
We have more information about healthcare workers and HIV infection.
Tattoos / piercing
Anything that potentially allows another person's body fluids to get into your bloodstream carries a risk. If the equipment has not been sterilised before having a tattoo or piercing, there could be a significant risk of exposure if the person before was HIV positive.
In the UK, and most other developed countries, there are hygiene regulations governing tattoo and piercing parlours to ensure all instruments used are sterile. If you are thinking of having a tattoo or piercing, ask staff at the shop what procedures they take to avoid infection.
You cannot get AIDS from. . .
Kissing
There is no scientific evidence indicating that any person has ever become infected through kissing an HIV positive person.
To become infected with HIV you must get a sufficient quantity of the virus into the bloodstream. Saliva does contain HIV, but the virus is only present in very small quantities and as such cannot cause HIV infection.
Unless both partners have large open sores in their mouths, or severely bleeding gums, there is no transmission risk from mouth-to-mouth kissing.
Sneezing, coughing, sharing glasses/cups, etc
HIV is unable to reproduce outside its living host, except under strictly controlled laboratory conditions. HIV does not survive well in the open air, and this makes the possibility of this type of environmental transmission remote. In practice no environmental transmission has been recorded.
This means that HIV cannot be transmitted through spitting, sneezing, sharing glasses, cutlery, or musical instruments.
You also can't be infected in swimming pools, showers or by sharing washing facilities or toilet seats.
Insects
Studies conducted by many researchers have shown no evidence of HIV transmission through insect bites, even in areas where there are many cases of AIDS and large populations of insects such as mosquitoes. Lack of such outbreaks, despite considerable efforts to detect them, supports the conclusion that insects do not transmit HIV.
HIV only lives for a short time and cannot reproduce inside an insect. So, even if the virus enters a mosquito or another sucking or biting insect, the insect does not become infected and cannot transmit HIV to the next human it feeds on or bites.
Injecting drugs with sterile needles
Injecting with a sterile needle and works will not transmit HIV as long as clean equipment is used each time and none of it is shared.
However, there are still many other risks associated with injecting drug use. If a person is on drugs (including alcohol) they may cloud judgement and make them more likely to become involved in risky sexual behaviour, increasing the chance of exposure to HIV.
AVERT has more information on the risks involved with recreational drug use and HIV.
Protected sex
If used correctly and consistently condoms are highly effective at preventing HIV transmission. A small minority believe condoms are not adequate protection and that 'some very small viruses can pass through latex'. Scientific tests have proven this theory to be unfounded however.1
Condoms are effective at preventing HIV during both vaginal and anal sex and can help to reduce the risks during oral sex too.
Further information can be found on our condoms page.
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