Friday, April 19, 2024

Receptive Vs Insertive Hiv Risk

Challenges In Calculating A Number

HIV Positive Youth – Risk Factors

It isn’t easy for researchers to calculate the risk of transmission from an exposure to HIV through sex. To do this effectively, a group of HIV-negative individuals need to be followed over time and their exposures to HIVboth the number of times they are exposed and the types of exposureneed to be tracked.

As you can imagine, accurately tracking the number of times a person is exposed to HIV is very difficult. Researchers ask HIV-negative individuals enrolled in these studies to report how many times they have had sex in a given period of time, what type of sex they had, how often they used condoms and the HIV status of their partner. Because a person may have trouble remembering their sexual behaviour or may not want to tell the whole truth, this reporting is often inaccurate.

Furthermore, a person does not always know the HIV status of their partner. For this reason, researchers usually enroll HIV-negative individuals who are in stable relationships with an HIV-positive partner . Researchers can then conclude that any unprotected sex reported by a study participant counts as an exposure to HIV.

Hiv And Maternal Transmission

HIV can be passed from mother to child during pregnancy, delivery, or through breastfeeding. If left untreated throughout these stages, there is a 15-45% chance of an HIV positive mother transmitting the virus to their child . However there are treatment options to prevent this from happening.

If pregnancy occurs and there has been potential HIV exposure, ask a healthcare provider about getting tested for HIV as early as possible. Taking medications called antiretroviral therapy as prescribed can reduce the viral load so that the baby has a very low chance of contracting HIV .

A person with HIV should not breastfeed their child, as breast milk can transmit HIV. Even if a person is taking ART and their viral loads are undetectable, they should still not breastfeed.

Interpreting The Numberswhat Additional Information Needs To Be Provided

Some clients may see these numbers and think their risk of HIV transmission is low. Therefore, caution is needed when interpreting them. If these numbers are provided to clients, they should be accompanied by information that helps shed light on why the risk may be higher than it seems.

Transmission can occur after one exposure.

It is important to emphasize that a person could become infected from having unprotected sex once or a person could have unprotected sex many times and not become infected, regardless of how low or high the risk per exposure is.

A risk of 1% would mean that an average of one infection would occur if 100 HIV-negative people were exposed to HIV through a certain type of sex. It does not mean that a person needs to be exposed 100 times for HIV infection to occur.

These are estimates of average risk in the absence of biological factors that increase risk.

The numbers in the table above are rough estimates. They are averages and do not represent the risk from all exposures to HIV through a certain type of sex.

The risk of HIV transmission may be much higher than these averages if biological risk factors are present. For example, research shows that STIs and some vaginal conditions, such as bacterial vaginosis, can increase the risk of HIV transmission by up to 8 times.6,7,8 As a result, the risk of an HIV-negative woman becoming infected through unprotected receptive vaginal sex could be closer to 1% if she has a vaginal STI.

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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 .

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, the chance of being exposed to the virus 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, of the 30,635 new HIV diagnoses in the U.S. in 2020, 68% were among gay and bisexual men.a 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. People who inject drugs remain at significant risk for getting HIV as well.

Visit our U.S. Statistics page for more information on how HIV affects different populations.

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How To Prevent The Spread Of Hiv

People living with HIV can use the following to prevent transmitting it to others:

  • Pre-exposure prophylaxis : This is a daily pill that contains two antivirals called tenofovir and emtricitabine. When a person takes it daily, PrEP can reduce the risk of acquiring HIV through sex by
  • of a recent potential HIV exposure.

Viral Load & Medications

If someone has HIV, this does not mean that they are restricted to celibacy. Many people with HIV still continue to have safe, enjoyable sex lives without spreading the virus. Always using a condom or barrier method is an important first step to prevent the sharing of HIV containing fluids.

Antiretroviral therapy : Another way to help decrease the risk of spreading HIV is to lower a personâs viral loadâthe amount of HIV in a personâs blood. Viral loads can be lowered using medications called antiretroviral therapy . These medications can lower the HIV viral load so much that HIV may not even be detectable on a blood testâthis is called an undetectable viral load . When a person’s viral load in undetectable, they have effectively no risk of transmitting the HIV virus to a non-infected partner . Taking these medication will help keep a person with HIV healthy while also helping prevent the spread of HIV to another person. This is not a cure, however. If medication is taken incorrectly or stopped, HIV viral loads will increase again and transmission can occur. Condoms and other barrier methods should still always be used during sex .

If you have HIV and have an undetectable viral load, you should still tell your partner before having sex.

Pre-exposure prophylaxis : Medication called pre-exposure prophylaxis can be taken daily to decrease the risk of contracting HIV if exposed .

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Factors That Increase Hiv Risk


Viral load is the amount of HIV virus particles in the blood of someone who has HIV. The higher someones viral load, the more likely that person is to transmit HIV. Viral load is highest during the acute phase of HIV and without antiretroviral therapy .

Taking ART daily as prescribed can make the viral load very lowso low that a test cant detect it . People with HIV who keep an undetectable viral load can live long, healthy lives. Having an undetectable viral load also helps prevent transmitting the virus to others through sex or sharing needles, syringes, or other injection equipment, and from perinatal transmission during pregnancy, birth, and breastfeeding.


If you have another sexually transmitted infection , such as syphilis, gonorrhea, chlamydia, or herpes simplex virus , you may be more likely to get or transmit HIV. Getting tested and treated for STIs can lower your chances of getting or transmitting HIV and other STIs.

If you have HIV and get and keep an undetectable viral load, getting an STI does not appear to increase the risk of transmitting HIV. But STIs can cause other problems.

If youre sexually active, you and your partners should get tested for STIs, even if you dont have symptoms. Find out more about STIs here. To get tested for HIV or other STIs, find a testing site near you.





Hiv Transmission Can Occur After Only One Exposure

What is the Probability of HIV Transmission after a risky Exposure?In Tamil/

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.

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Internal And External Review

The results presented here were vetted with CDC scientists as the project progressed. This internal iterative process included a critical review of the study design and statistical approach of each peer-reviewed publication upon which our new estimates relied as well as of our decision to present summary estimates from published meta-analyses. Our preliminary new estimates were critically reviewed by subject matter experts external to CDC , each of whom signed a nondisclosure agreement to ensure confidentiality.

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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Putting A Number On It: The Risk From An Exposure To Hiv

This information was provided by CATIE . For more information, contact CATIE at 1-800-263-1638.

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?

Study Design Site And Population

PrEP and PEP

The study was conducted at a local non-governmental organization which was established in 2008 and located in the urban area of central Changsha, the capital city of Hunan Province in south-central China. Considering the strong discrimination against MSMs in this city, the main approach to involving MSMs in free HIV testing is through NGO services for MSMs. The staff of this organization has been trained for HIV-related counseling services. With guidance and support from the Changsha Centre for Disease Control and Prevention , HIV prevention services were provided for MSMs, including peer education, condom distribution, and peer support. For MSMs who needed HIV testing service, the NGO staff would provide pre-test counseling, blood sampling, post-test counseling, referral services, as well as continuous support if needed. The NGO staff sent the blood samples to CDC for the screening test and confirmatory test . The laboratory test for HIV was free. Some MSMs chose to pay RMB 30 for a rapid test on the site. The site successfully collaborated with the Bill & Melinda Gates and the Global AIDS Foundations and more than 1000 people received HIV testing each year.

A gift package rather than direct payment was given to the participants as a compensation for time and transportation after the survey. The primary researchers provided their contact information to the participants and promised medical advice and help if needed.

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How Can You Prevent Getting Or Transmitting Hiv Through 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 HIV medicine exactly as prescribed. People with HIV who take HIV medicine as prescribed and get and keep an undetectable viral load can live long and healthy lives and will not transmit HIV to their HIV-negative partners through sex. This is sometimes called HIV treatment as prevention or undetectable = untransmittable . There also are other options to prevent transmitting HIV, below.

No 4 Having Vaginal Sex : 1 In 1250

Most women who get HIV are infected through vaginal sex. In such cases, an HIV-positive man transmits the virus to his female partner through preseminal fluid or ejaculate, which allows HIV to pass through the linings of the and cervix.

  • Reduce the risk. In theory, withdrawal practiced as a safety measure may help reduce a womans risk of contracting HIV from an HIV-positive partner, but because the virus can be found in preseminal fluids, the method may not be effective. Using condoms, however, can help lower the odds of transmitting HIV by 80 percent or more, according to the World Health Organization.

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No 1 Sharing A Needle: 1 In 159

About 6 percent of the HIV diagnoses in 2015 can be attributed to the use of injection drugs, according to the Centers for Disease Control and Prevention . The reason is that needles, syringes, and other equipment can contain blood, and therefore HIV, which can then be directly transmitted into the bloodstream. Under the right environmental circumstances, the virus can survive in a used needle for up to 42 days, according to the U.S. Department of Health and Human Services. In addition, using drugs can lower peoples inhibitions, making them less likely to use a condom during sex or to take preventive HIV medications, further increasing their risk.

    • Reduce the risk. Although the number of HIV diagnoses among people who inject drugs has declined by 48 percent from 2008 to 2014, according to the CDC, experts worry that the rising opioid epidemic is putting new people at risk for getting the virus. To find substance abuse help, call the Substance Abuse and Mental Health Services Administrations national helpline at 1-800-662-HELP or visit its website,, for a list of treatment facilities near you.
    • Reduce the risk. People who inject drugs can help lower their risk of exposure to HIV by using a sterile needle and syringe for each injection sterile needles can be obtained without a prescription at pharmacies and through syringe services programs at state or local health departments.

Reducing Your Personal Hiv Risk

Some Ways You Can Contract HIV and Their Risks

Arguably the most important factor in assessing the likelihood of HIV transmission is the infected person’s viral load. Data suggests that the risk of an HIV-infected person with an undetectable viral load transmitting the virus is essentially zero.

The strategy called treatment as prevention strongly supports the use of antiretroviral therapy to reduce the infectivity of a person with HIV. It also reinforces the need for early testing to mitigate risk in mixed-status couples.

Knowing your serostatus and that of your partner allows you to make an informed choice on how to better protect yourselveswhether it be to abstain from high-risk activities, use condoms, or explore pre-exposure prophylaxis as a means to reduce the HIV-negative partner’s susceptibility to infection.

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Changes In Estimated Hiv Prevalence And Associated Variables

Estimated self-reported HIV prevalence increased from 19.6% to 26.8% between 1997 and 2002 . The proportion of those ever tested for HIV increased to 96.4%, up from 92.0% . Among HIV-negative men, the proportion tested for HIV in the past year was virtually unchanged . The median time period since the respondent first tested positive for HIV was between 7 and 8 years in 1997 and increased to between 12 and 13 years in 2002, indicating that the great majority of infections were long standing. In 1997, 9.3% of HIV-positive men had first tested positive within the past 2 years, compared with 8.4% in 2002.

Hiv: How High Is Your Risk

Your highest risk for contracting HIV, is having unprotected sex with someone who is busy becoming HIV-positive, who might think he/she is HIV-negative, but is in fact seroconverting. This is the time when the viral load is at its highest. In other words, it is actually statistically safer to have protected sex with someone who is HIV-positive, than it is to have unprotected sex with someone who thinks he/she is negative, but who is actually seroconverting.

Estimated per act risk for acquisition of HIV, by exposure route

Exposure route Risk per 10 000 exposures to an infected source Percentage

The risk of HIV infection in heterosexual couples

HIV-positive woman with low viral load None
Both male and female with condom
HIV-positive woman with high viral load None
Both male and female with condom
HIV-positive man with low viral load None
Both male and female with condom
HIV-positive man with high viral load None
Both male and female with condom
Both male and female HIV-positive None
Both male and female with condom

* It is safer to withdraw even with a condom

The risk of HIV infection in gay couples

HIV-positive woman with low viral load None
HIV-positive woman with high viral load None
HIV-positive man with low viral load None
HIV-positive man with high viral load None

* It is safer to withdraw even with a condom

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