Putting A Number On It: The Risk From An Exposure To Hiv
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Author: James Wilton
Service providers working in HIV prevention are often asked by their patients and clients about the risk of HIV transmission from an exposure to HIV through sex. What do the latest studies tell us about this risk? And how should we interpret and communicate the results?
Is The Risk Of Hiv Different For Different Groups
HIV can affect anyone regardless of sexual orientation, race, ethnicity, gender, age, or where they live. However, certain groups of people in the United States are more likely to get HIV than others because of particular factors, including the communities in which they live, what subpopulations they belong to, and their risk behaviors.
Communities. When you live in a community where many people have HIV infection, the chance of being exposed to HIV by having sex or sharing needles or other injection equipment with someone who has HIV is higher. You can use CDCs HIV, STD, hepatitis, and tuberculosis Atlas Plus to see the percentage of people with HIV in different U.S. counties and states, as well as other data. Within any community, the prevalence of HIV can vary among different subpopulations.
Subpopulations. In the United States, gay, bisexual, and other men who have sex with men are the population most affected by HIV. According to CDC, in 2018, gay and bisexual men accounted for 69% of new HIV diagnoses. By race/ethnicity, Blacks/African Americans and Hispanics/Latinos are disproportionately affected by HIV compared to other racial and ethnic groups. Also, transgender women who have sex with men are among the groups at highest risk for HIV infection, and injection drug users remain at significant risk for getting HIV.
Visit our U.S. Statistics page for more information on how HIV affects different populations.
How Is Hiv Transmitted Through Needles
HIV isnt transmitted only through sexual contact. Sharing needles also puts a person at higher risk of contracting HIV.
When a needle is injected into a persons body, it breaks the skin barrier. If the needle has already been injected into another person, it can carry traces of their blood, along with any infections they have. The contaminated needle can introduce these infections into the second persons body.
Researchers dont know if having an undetectable viral load reduces the risk of HIV transmission through shared needles, but its reasonable to assume it may provide some risk reduction.
HIV can affect anyone. Whatever their age, gender, sexuality, ethnicity, or race, everyone should take steps to protect themselves. But due to socioeconomic factors, some demographic groups have higher HIV transmission rates and generally are more affected by HIV.
According to the CDC , the general demographic traits most affected by HIV are:
Transgender women are also highly impacted by HIV transmissions as a population, reports the CDC .
These groups are disproportionately affected by HIV, but they arent inherently at greater risk of contracting HIV. An individuals personal risk depends on their behaviors, not on their age, gender, sexuality, ethnicity, race, or any other demographic factor.
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How Is Hiv Transmitted
The person-to-person spread of HIV is called HIV transmission. People can get or transmit HIV only through specific activities, such as through sex or injection drug use. HIV can be transmitted only in certain body fluids from a person who has HIV:
- Blood
- Vaginal fluids
- Breast milk
HIV transmission is only possible if these fluids come in contact with a mucous membrane or damaged tissue or are directly injected into the bloodstream . Mucous membranes are found inside the rectum, the vagina, the opening of the penis, and the mouth.
In the United States, HIV is spread mainly by:
- Having anal or vaginal sex with someone who has HIV without using a condom or taking medicines to prevent or treat HIV
- Sharing injection drug equipment , such as needles, with someone who has HIV
HIV can also spread from a woman with HIV to her child during pregnancy, childbirth , or breastfeeding. This is called mother-to-child transmission of HIV.
You can’t get HIV from casual contact with a person who has HIV, such as a handshake, a hug, or a closed-mouth kiss. And you can’t get HIV from contact with objects such as toilet seats, doorknobs, or dishes used by a person who has HIV. Use the ClinicalInfo You Can Safely ShareWith Someone With HIV infographic to spread this message.
Does Rectal Fluid Contain Hiv

In an HIV-positive person, the mucous membranes throughout the body can contain a lot of HIV. This is because these membranes are rich in immune cells, which are the cells that HIV likes to infect and replicate within.1 Since so much HIV replication can occur at the mucous membranes, the virus is able to enter the mucus that the membranes produce. As a result, mucus produced by an HIV-positive person can contain HIV , which can potentially be transmitted to someone else.
The mucous membranes of the rectum, and the mucus they produce , are no exception. Several studies show that HIV can be found in the rectal fluid of a person living with HIV.2,3,4,5,6 In fact, one study of 64 HIV-positive men found that, overall, the average amount of virus in their rectal fluid was higher than in their semen and blood.4
Why might rectal fluid contain more HIV than other bodily fluids? It turns out that the majority of the immune cells in the body including the cells that are a major target for HIV are located in the mucous membranes of the gastrointestinal tract, which includes the rectum.7 There are a lot of immune cells in the gastrointestinal tract because it has a very large surface area. Also, a large number of immune cells are needed to help to protect the gut from the foreign germs in our food and to control the growth of the friendly germs living in our gut.
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Stay On Top Of Medications Including Art Prep And Pep
Weve come a long way in HIV treatment and prevention, and some drugs can help you reduce the risk of transmission if youre living with HIV or are having sex with someone who is.
Talk with a medical professional about:
- ART: Antiretroviral therapy helps a person living with HIV stay healthy by lowering the viral load. Most people who take it as prescribed can lower their viral load to an undetectable level, so they cant transmit the virus to others.
- PrEP: A person whos HIV-negative significantly reduces their risk of contracting HIV by taking PrEP consistently.
- PEP: In the event of potential exposure to HIV, PEP is available for emergency use. It can help prevent HIV infection if started within 72 hours of exposure.
How Can I Reduce My Risk Of Getting Hiv
- Get tested for HIV. Talk to your partner about HIV testing and get tested before you have sex. Use this testing locator from the Centers for Disease Control and Prevention to find an HIV testing location near you.
- Choose less risky sexual behaviors. HIV is mainly spread by having anal or vaginal sex without a condom or without taking medicines to prevent or treat HIV.
- Use condoms every time you have sex. Read this fact sheet from CDC on how to use condoms correctly.
- Limit your number of sexual partners. The more partners you have, the more likely you are to have a partner with poorly controlled HIV or to have a partner with a sexually transmitted disease . Both of these factors can increase the risk of HIV transmission.
- Get tested and treated for STDs. Insist that your partners get tested and treated, too. Having an STD can increase your risk of getting HIV or spreading it to others.
- Talk to your health care provider about pre-exposure prophylaxis . PrEP is an HIV prevention option for people who don’t have HIV but who are at risk of getting HIV. PrEP involves taking a specific HIV medicine every day to reduce the risk of getting HIV through sex or injection drug use. For more information, read the ClinicalInfo fact sheet on Pre-Exposure Prophylaxis .
- Don’t inject drugs. But if you do, use only sterile drug injection equipment and water and never share your equipment with others.
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Hiv Treatment & Undetectable
Todays HIV treatments, called antiretroviral therapy or ART, are extremely effective. Some treatments are a single tablet. Long-acting injectable medications are likely to be approved and available soon. Medicine has come a long way since the first HIV treatment options became available in the 1990s.
There is still no functional cure for HIV, but ART can help people live long, healthy lives. Todays medications are provided in combinations that reduce a persons viral load to levels so low its undetectable. People who become undetectable cannot transmit the virus to others.
Viral load is a term that describes how much virus a person living with HIV has in their body.
Without HIV medications, the virus replicates which causes the amount of virus in the body to increase.
HIV medications prevent HIV from making copies of itself. Then, the amount of HIV in the body goes down.
To see how well HIV treatments are working, doctors and other providers measure the amount of virus in the blood and report a measurement called your viral load. Its simply a measurement of how many copies of the virus are in a single unit of blood.
A very low amount of virus may even be undetectable by viral load tests . A common undetectable level is < 20 copies per milliliter of blood. Low viral loads are those that are less than 200 copies per milliliter. Very high viral loads can be over 500,000 copies per milliliter.
No 3 Having Anal Sex : 1 In 909
The insertive partner is less likely than the receptive partner to get the infection from an HIV-positive partner. However, bodily fluids carrying the virus can enter the insertive persons body through the urethra or any cuts or sores on the penis.
- Reduce the risk. If the insertive partner uses a condom, that can cut the risk of HIV transmission by an average of 63 percent, according to the CDC. You can help lessen the chance that the condom will slip or break by using water- or silicone-based lubricants. In addition, be aware that condoms dont fully protect against certain sexually transmitted diseases that can be contracted through skin-to-skin contact, like syphilis and herpes.
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Anal Intercourse Between Men And Women
Anal intercourse between men and women has generally not received as much attention as anal intercourse between men. However, there is evidence that anal sex is practised by large numbers of sexually active adults. In 2010, 11% of women and 13% of men in the United Kingdom report having anal intercourse in the past year, with younger generations being more likely to report it .
Unprotected heterosexual anal sex probably plays an important role in HIV transmission among heterosexuals, although reliable estimates are lacking .
What Are My Chances Of Getting An Std
Know risks of what you can get if your partner is Infected.
Performing Oral Sex – on a Man
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*You could be at risk if the receiver has just topped someone else.
Following safe sex activities and practices listed below may also protect you from getting a STD
- Kissing, mutual masturbation, and frottage or dry humping are considered safer sex activities, with little to no risk of STD transmission.
- Oral sex is considered low risk in terms of getting HIV. There is no risk of getting HIV from receiving oral sex . There is very little risk of getting HIV from giving oral sex, but having cuts or sores in your mouth, gum disease, having an STD in your throat, or recent dental work increases your risk.
- Condom use reduces transmission risk even further. Using latex condoms significantly reduces the risk of contracting STDs during anal, vaginal and oral sex.
- Washing hands and the genital area thoroughly before and after oral-anal sex reduces the risk of transmission of most of the listed STDs and conditions.
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What Are The Signs And Symptoms Of Hiv
Within a few weeks of getting HIV, some people get flu-like symptoms that last for a week or two, but others have no symptoms at all. After initial infection, people may not have any symptoms for years. HIV can be controlled with the right medical treatment and care. However, if its left untreated, it may develop into AIDS .
How Can You Prevent Getting Or Transmitting Hiv Through Sex

There are several ways to prevent getting or transmitting HIV through anal or vaginal sex.
If you are HIV-negative, you can use HIV prevention medicine known as pre-exposure prophylaxis or post-exposure prophylaxis to protect yourself. You can also use other HIV prevention methods, below.
If you have HIV, the most important thing you can do to prevent transmission and stay healthy is to take your HIV medicine , every day, exactly as prescribed. People living with HIV who take HIV medicine daily as prescribed and get and keep an undetectable viral load have effectively no risk of sexually transmitting HIV to their HIV-negative partners. Read more about Treatment as Prevention. There also are other options to choose from, below.
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Can You Get Hiv/aids From Someone’s Blood Touching Your Open Sore
HIV transmissions as a result of one person’s blood entering another person’s open sore or wound are theoretically possible, but in practice hardly ever happen. Only a handful of cases have ever been documented.
If a person is living with HIV and they do not have an undetectable viral load, and their blood directly enters the bloodstream of another person, HIV may be passed on. For example, this is how HIV is usually transmitted when people share syringes or needles used to inject drugs.
However, HIV transmission following limited contactfor example, blood touching an open soreis much less likely.
If you are concerned about an incident in which you had contact with another person’s blood, it’s worth noting a few points:
- If the blood came into contact with undamaged, unbroken skin, there is no HIV risk whatsoever.
- HIV is not transmitted through surface scratches, such as paper cuts.
- A cut or wound that is in the process of healing and scabbing over is unlikely to allow entry of the other person’s blood.
- HIV does not survive long outside the body, so the risk from blood left behind on objects is minimal.
- The handful of documented cases of HIV transmission involving fights or accidents have involved serious injuries and profuse bleeding.
How Do I Get Prep
PrEP can only be prescribed by a doctor, so you will need to talk to a physician about taking it. Your doctor may ask you some questions to determine your risk factors for HIV transmission and then discuss your options.
You will first need to be tested to ensure that you do not currently have HIV. This involves a simple blood test and the results will be available in a matter of days.If you have insurance, the cost of HIV should be completely covered or you may have to make a small co-pay. Some or all of your medication costs may also be covered under Medicare or Medicaid. If you do not have insurance, there are some options to help you be able to afford PrEP, including the Cost Assistance program from Gilead.
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Implications For Hiv Transmission And Prevention
Anal sex is a common practice among men who have sex with men, heterosexual men and women, and transgender individuals and is a known risk factor for HIV infection and transmission.11,12,13,14 In a recent nationally representative survey of almost 6,000 men and women in the United States , approximately 20% of women between the ages of 18 to 39 reported engaging in anal sex in the past year, as did approximately 25% of men between the ages of 25 to 49.15
HIV transmission
Rectal fluid has implications for HIV transmission through anal sex when the HIV-negative person is the insertive partner . Research show that this type of anal sex can carry a significant risk of HIV transmission. In fact, the average risk of HIV infection through a single act of condomless insertive anal sex with an HIV-positive partner is slightly higher than through vaginal sex but much lower than if the HIV-negative person takes the receptive role during anal sex.16,17
Rectal fluid undoubtedly contributes to the risk of HIV transmission through anal sex where the insertive partner is HIV negative. We know that for HIV transmission to be possible, a fluid that contains HIV must come into contact with specific parts of the body that are vulnerable to HIV infection. If an HIV-negative person has insertive anal sex with an HIV-positive partner, rectal fluid containing HIV can come into contact with the urethra and/or the penis foreskin. Both the urethra and foreskin are vulnerable to HIV infection.
Be Aware Of Potential Symptoms
If you have sex, knowing what symptoms could indicate an STI is a must.
See a healthcare professional if you notice any of the following:
- unusual discharge from the anus, penis, or vagina
- changes in urination, like pain or burning, frequency, or urgency
- sores, warts, or blisters on or around your genitals or anus
- unusual vaginal bleeding, like after sexual activity or between periods
- genital itching
Are certain activities higher risk?
Penis-in-anus sex is the riskiest, especially for the receptive partner because the rectums lining is thin, making it easier for the virus to enter the bloodstream.
Penis-in-vagina sex, though not as risky, is also considered higher risk activity for both parties.
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