How Is Hiv Transmitted
HIV is transmitted between humans through the exchange of certain types of bodily fluids. Bodily fluids that can transmit HIV include blood, semen, breast milk, and vaginal fluids .
Not all body fluids can transmit HIV. The following cannot transmit HIV:
- Exchanging saliva, like through closed-mouth kissing or sharing drinks/utensils
- Coming in contact with an HIV positive personâs tears, sneezes, or sweat
- Ordinary physical contact, such as hugging, hand shaking, or touching shared objects like cutlery, cups, or toilet seats .
- Air or water
- Pets and insects cannot carry the virus and infect you, because transmission of HIV is only between humans .
While care needs to be taken in some situationsâlike when having sex or when open injuries are presentâthis certainly does not mean that it is unsafe to be around people with HIV. Think of how you interact with the vast majority of peopleâbodily fluids are not exchanged. Harboring discriminatory thoughts only perpetuates a fearful stigma against someone with HIV, which only hurts the person who has it.
HIV is often transmitted through sexual activity and drug use in adults in the United States . Maternal transmissionâfrom mother to childâis how the infection is spread to infants .
Lowering The Risk Of Sexual Transmission
There are several protective measures which dramatically reduce the risk of HIV transmission during sex. You can find out more about these on other pages.
Antiretroviral drugs used by a person who does not have HIV to be taken before possible exposure to HIV in order to reduce the risk of acquiring HIV infection. PrEP may either be taken daily or according to an event based or on demand regimen.;
Undetectable viral load: when people with HIV take effective treatment,;the amount of HIV in their body fluids falls drastically, to the point where they cannot pass HIV on to their sexual partners. An extremely low level of HIV in body fluids is referred to as an;undetectable viral load. The knowledge that this prevents transmission is often referred to ‘Undetectable equals Untransmittable’ .
PrEP: if the HIV-negative person takes antiretroviral medications as;pre-exposure prophylaxis ,;this significantly reduces the risk of acquiring HIV. The most common form of PrEP is in a tablet, but it can also be provided as a vaginal ring or an injection.
Condoms: if;male condoms or female condoms;are used, this significantly reduces the risk of acquiring HIV.
Male circumcision: if you are circumcised, this partially lowers your risk of acquiring HIV during vaginal sex.
Estimated Hiv Transmission Risk Per Exposure
The estimates below should not be considered definitive but rather serve as a;means to understand the relative risk of HIV by exposure type. The numbers are based on a meta-analysis of several large-scale studies which looked specifically at per-exposure risk.
|Mother-to-child, on ART with undetectable viral load||0.1%|
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What To Do If You’re Not Sure
HIV hotlines are used to getting calls from people who are afraid they have been infected through casual contact. Perhaps the person was involved in a fight or came into contact with someone who was bleeding. Others may worry about having deep kissed someone who may or may not have HIV.
While the likelihood of infection in these cases would be considered negligible to nil, people will often want a 100% guarantee that they’re going to be fine; nothing less will suffice.
In such cases, doctors will usually take the opportunity to perform an HIV test and perform pre- and post-test counseling to better understand what the person knows about HIV and answer any questions they might have.
If there is a risk of actual transmission, however small, the doctor may opt to prescribe a 28-day course of HIV medications known as post-exposure prophylaxis which may avert infection if treatment is started within 72 hours of the suspected exposure.
In cases where the person’s fears seem extreme and unreasonable, counseling may also be needed to address the possibility of AIDS phobia or other possible anxiety disorders.
How Is Hiv Passed Through Needles And Other Drug Use Or Body Work Equipment
HIV can be passed through blood that remains in used needles or other drug injection equipment, even if the amount of blood is so small it cant be seen. When a used needle containing blood with HIV breaks the skin of another person, HIV can get directly into their bloodstream. Once inside the bloodstream it can then cause a permanent infection. In the same way, HIV can be passed on by reusing unsterilized equipment for tattooing or piercing and through accidental needlestick injuries.
Sharing needles or other equipment used to inject drugs is the most common way that HIV is transmitted through broken skin. When a person injects drugs, blood can get into the needle/syringe or on other equipment they are using to inject or prepare their drugs. When someone uses a needle/syringe that has already been used by another person, there is a possibility that blood containing HIV is present. When a person prepares and injects drugs using shared equipment, blood that may contain HIV can directly enter their bloodstream through the broken skin. This is an efficient mode of transmission because the immune cells are the only natural defence against this type of HIV transmission. A larger amount of residual blood in the needle/syringe or other equipment and a higher amount of HIV in the blood can both increase the risk of injection-related HIV transmission.
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Where Is Hiv Found In The Body
Looking at the first two conditions for HIV transmission , let’s examine some of the so-called “bodily fluids” that can contain HIV.
Infectious “Bodily Fluids”
HIV can be transmitted from an infected person to another through:
- Vaginal secretions
- Breast milk
Blood contains the highest concentration of the virus, followed closely by semen, followed by vaginal fluids. These are the three basic fluids that infect adults with HIV.
The risk from these fluids can be worsened or lessened depending on how they get into someone else’s body, which we will discuss below.
Breast milk can contain a high concentration of the virus, but in this situation, transmissibility depends on who and how. An adult can ingest a small amount of breast milk at minimal risk. But an infant, with its very small body and newly forming immune system, consumes vast quantities of breast milk relative to its body weight. Therefore an infant is at risk from breast milk, whereas an adult probably is not.
Possibly Infectious “Bodily Fluids”
HIV might be transmitted from an infected person to another through:
- pre-seminal fluid
Pre-seminal fluid is a clear fluid that lubricates men’s urethras. It is produced by a different gland than semen. Pre-seminal fluid can contain small amounts of HIV, and so there is a potential risk. However, in practice, the risk is much, much lower than that from blood, semen or vaginal fluid. As in all transmission situations, risk depends on where the fluid is going.
Factors That Increase The Risk Of Sexual Transmission
Not every act of unprotected sex with an HIV-positive person results in HIV transmission. But other factors can make HIV transmission more likely.
If the HIV-negative person has an untreated sexually transmitted infection , the risk is greater.
Just as HIV treatment and an undetectable viral load prevents HIV transmission, a;high;viral load makes it more likely. Viral load refers to the quantity of HIV in a persons body fluids. It is extremely high in the first few weeks after a person is first infected with HIV. It may also be high if a person does not take HIV treatment and has advanced disease. People who have HIV without realising it cannot take HIV treatment, so there is a strong possibility that they have a high viral load. ;
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How Is Hiv Spread Through Sex
You can get infected from sexual contact with someone who has HIV. Sexual contact that can transmit HIV includes:
- vaginal sex
- anal sex
- oral sex
If you have sex, the best thing you can do to prevent HIV infection is practice “safer sex” with any partner who is not proven to be HIV negative . To do so, always use protection–this could include using a condom, dental dam, or other latex barrier, and/or PrEP . It is also important to avoid “rough sex” or other activities that might cause bleeding. If you use lube with a condom, make sure it is water-based, not oil-based. Oil-based lube causes latex condoms to break. See more tips for using condoms; note that, if used correctly and consistently, condoms also protect against other sexually transmitted infections and against pregnancy.
If you have unprotected sex with someone who is infected, it doesn’t mean that you will be infected, too. But there is always a chance, especially if your partner is not on effective HIV medicines. Using condoms and PrEP reduces your risk.
HIV is NOT spread by:
- hugging or massage
- sex toys you don’t share
- daily living with someone who has HIV
For more information, see Sex and Sexuality in the Daily Living section.
Doubts Persist Even When Risk Is Statistically Zero
Despite increased public awareness about HIV, there remains a lot of confusion about how you can get infected and how you cannot. For example, even though people understand that you can’t get HIV from utensils, there are many who will experience a twinge of concern if they learned that the chef of their favorite restaurant has HIV.
HIV has a way of spurring anxieties in even the best of us and, with it, our sense of reason. Relieving those anxieties often requires us to do more than just lay out the rules. Instead, we need to understand what conditions are required for an infection to take place and why things like hugging, touching, sneezing, or kissing simply do not satisfy those conditions.
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Blood Transfusions And Organ Donation
The risk of contracting HIV from a blood transfusion, other blood products, or organ donation is now extremely rare in the United States. All donated blood or blood products in the United States are tested for several types of bloodborne pathogens, including HIV.
Blood donations that test positive for HIV are safely discarded and dont enter the blood supply. The risk of HIV transmission during a blood transfusion is conservatively estimated to be
, there are no known instances of HIV being transmitted by receiving a tattoo or piercing. However, its technically possible for transmission to occur if equipment or ink is reused or shared.
Hiv Survival Outside The Body
Generally, when people ask the question, “How long can HIV survive outside the body?” they have come into contact with some body fluid that they think might contain HIV, and are worried about transmission. Almost always these questions are about casual contact, and we know the virus is not transmitted except during unprotected sex, sharing needles, or through significant and direct exposure to infected blood.
The length of time HIV can survive outside the body depends on:
- the amount of HIV present in the body fluid;
- what conditions the fluid is subjected to
In a laboratory, HIV has been kept viable for up to 15 days, and even after the body fluid containing it had dried. However, these experiments involved an extremely high concentration of the virus which was kept at a stable temperature and humidity. These conditions are very unlikely to exist outside of a laboratory. HIV is very fragile, and many common substances, including hot water, soap, bleach and alcohol, will kill it.
The chances of becoming infected with HIV by handling a body fluid are extremely small, because that fluid will rarely have access to a person’s bloodstream. However, anyone handling blood, semen or vaginal fluids should be careful to avoid touching them with broken skin or getting them into mucous membranes .
Is Someone Who Takes Hiv Drugs Able To Transmit Hiv
Some people believe that taking antiretrovirals or having an “undetectable viral load” means that they can’t transmit HIV to their sexual partners. That is not true. A person who takes HIV treatments — even those who have “undetectable” viral load counts — can still transmit HIV.
Effective drugs, taken properly, can significantly decrease viral load . It is known that the higher one’s viral load, the more likely one is to transmit the virus and the lower one’s viral load, the less likely one is to transmit the virus. But, regardless, HIV can still be transmitted. It is also important to note that viral load can change from day to day, so one can never be certain of their viral load count at a particular time. In addition, viral load tests only reflect the amount of virus in the blood, not necessarily the level of virus in other bodily fluids, such as semen and vaginal fluid.
Common Bodily Fluids What Makes The List
Bodily fluids come in all forms and although unpleasant to think about, they are all vital to our health. Bodily fluids are just like the fluids in our cars. Gas, oil, antifreeze and windshield wiper fluid all serve a role in helping our cars function properly.
Below is a list of bodily fluids and the role each one plays in;keeping our bodies healthy and running on all cylinders.;
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A Short List Of Diseases That Can Be Transmitted Through Bodily Fluids
Although bodily fluids work hard to keep us healthy, many are widely recognized as transmitters for human diseases.
Some examples of diseases that can be transmitted through bodily fluids are:
Means And Requirements For Hiv Transmission
People may become infected with HIV if they engage in specific risk behaviors or if they are exposed through needlestick injuries . Other blood contact with mucous membranes or non-intact skin provides a possible, but not probable, chance of transmission.
HIV is transmitted through:
- Unprotected anal, vaginal, and oral intercourse
- Sharing needles or other injection equipment
- A mother passing the virus to her baby either before or during birth
- An infected woman breastfeeding her infant
- Accidental needlestick injuries, or infected body fluid coming into contact with the broken skin or mucous membranes of another person
- A transfusion prior to 1986 of HIV-infected blood or blood products
In extremely rare cases, HIV can be transmitted by sharing razors or toothbrushes, if infected blood from one person was deposited on the toothbrush or razor and the blood entered the bloodstream of another person.
The transmission of HIV depends upon:
- The availability of the infectious agent in sufficient quantity
- The viability of the infectious agent
- The virulence of the infectious agent
- The ability of the infectious agent to reach the bloodstream, mucous membranes, or broken skin of a potential host
One of the predictors of the infectious level of an HIV-positive person is viral load, which is how much HIV is present in the bloodstream. Studies show a clear connection between higher viral load in the blood and increased transmissibility of HIV.
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Hiv Transmission Can Occur After Only One Exposure
Assigning an actual percentage to the “riskiness” of a certain activity is a tricky business. While statistics may suggest that there is only a 1-in-200 chance of getting infected by such-and-such activity, that doesn’t mean you cant get infected after only one exposure.
Instead, a 0.5%;”per exposure” risk is meant to indicate that an average of one infection will occur out of 200 people who engage in a particular activity. It doesn’t mean that;you need to do something 200 times in order to get infected.
It’s important to remember that risk estimates are based on two factors and two factors alonethat one person has HIV and the other doesn’t. Additional co-factors, such as co-existing sexually transmitted infections , general health, and the infected person’s viral load,;can further compound risk until a;low-risk activity is suddenly considerably higher.
Estimating Transmission Risk By Exposure Type
When discussing HIV risk, it’s important to first establish the four conditions that must take place in order for HIV transmission to occur:
Determining whether an activity is “high risk” or “low risk” is, therefore, dependent upon how efficiently an activity satisfies each of these four conditions.
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