Your odds of getting HIV

In this section, our expert doctor will answer the most frequently asked questions about the odds of getting HIV.

• How is HIV infection trending in the US?

  The number of newly diagnosed HIV cases has been steadily decreasing since the mid-1980s epidemic:

  • Two-thirds drop from the height of the pandemic to now
  • One-third drop in the last decade

  	New HIV cases in the US
  2000	41,960
  2010	39,867
  2018	37,428

  
  

  The decrease is primarily due to three things:

  • Behavioral changes, such as safer sex practices (condom use), avoiding sharing needles, and mutual monogamous relationships
  • Medication (PEP and Prep) availability
  • Good suppressive medication for HIV-positive persons that makes the virus undetectable and stops it from spreading

• What are the statistics on HIV contraction routes for males and females?

  Knowing the most common routes of contracting HIV helps us to know the chance of contracting HIV in that particular group.

  
  

  Here we summarize different routes through which males and females get HIV. The information below is based on 2018 statistics.

  
  

  Routes for contracting HIV in general

  • 58% male-to-male contact
  • 26% heterosexual contact
  • 11% drug injection
  • 5% combination of drug injection and male-to-male sex

  
  

  Routes through which males contract HIV

  • 74.5% male-to-male contact
  • 10.55% heterosexual contact
  • 8.1% drug injection

  
  
  

  Routes through which females contract HIV

  • 79.6.% heterosexual contact
  • 19.9% drug injection
  • 1% other routes (perinatal, transfusion, etc.)

  

• What groups of people are at greater risk of contracting HIV?

  If you belong to one of these categories of people, your chance of contracting HIV is higher:

  • Homosexual males
  • People practicing anal sex
  • People with multiple sex partners
  • People having unprotected sex
  • People with other STDs (especially those that can cause a sore or discharges, because the chance of getting HIV through damaged areas is 6 to 10 times higher)

• What factors make transmitting HIV to a sex partner more likely?

  • The infectiousness of the HIV-positive person (the HIV viral load at the time of the contact)
  • How susceptible the partner is (people with genital sores, vaginal discharge, genital irritation, or warts are more susceptible)
  • Timing: the partner is more likely to contract the disease from an HIV-positive person who is newly diagnosed and symptomatic)

• Is a newly diagnosed HIV patient more likely to transmit the disease?

  The chance of contracting HIV from a newly diagnosed person is much higher, especially if the person is symptomatic. This is mainly due to these people having a very high HIV viral load. Here are the important facts to know:

  • The chance of passing the infection during the first three months after contracting HIV is 26 times higher than during the months and years that follow
  • The chance of contracting HIV when the infected person has acute HIV symptoms is much higher and can go up to 2% for vaginal sex (normally, it’s 0.08%) and 20% for receptive sex (normally, it’s 1.38%)

• Is one gender at higher risk of contracting HIV than another?

  Females are more likely than males to contract HIV:

  
  

  0.08% (females) vs. 0.04% (males)

  
  

  Females have a larger mucosal area that’s involved in sexual contact. The bigger the area, the greater the chance of micro cuts and HIV transmission.

  
  

  Females under the age of 17 are especially at risk because they have underdeveloped cervixes and produce less vaginal fluid, which increases the chance of micro abrasions.

• What is the chance of contracting HIV through multiple unprotected contacts?

  The cumulative risk of females getting HIV through multiple unprotected contacts involving vaginal sex with HIV-positive males might be up to 10% (calculations based on 100 sexual encounters).

  
  

  We could find no data for other groups. So, we will compare other groups to receptive vaginal sex:

  • Receptive anal sex (“bottom”) is 18 times riskier than receptive vaginal sex
  • Receptive vaginal sex (females) is 2 times riskier than insertive vaginal sex (males)

• What is the chance of HIV contraction with multiple protected contacts?

  No data are available on the chance of passing an HIV infection with multiple protected contacts, but we calculated the risk based on the following facts:

  • Consistent use of condoms decreases the chance of contraction by 70%
  • These are the figures for the cumulative risk with unprotected contacts:
    • 10% for females
    • 5% for males

  Based on these numbers, we calculated the chance of contracting HIV through multiple protected contacts:

  • 3% for heterosexual females
  • 1.5% for heterosexual males

• What can you tell me about the risk of HIV transmission with oral sex (giving and receiving)?

  The risk of getting HIV from oral sex is considered to be very low—close to zero chance of passing or contracting HIV. Here’s why:

  • The oral mucosa is very stable and rarely develops micro abrasions during sex, even if sperm or blood enter the mouth
  • Most people who have oral sex also have vaginal and/or anal sex during the same encounter, so it is tricky to calculate the risk of oral sex separately

  Factors that increase the chance of oral HIV transmission

  
  

  A person whose mouth is exposed to ejaculate or vaginal fluids is at greater risk of contracting HIV if they have sores in their mouth and/or bleeding gums.

  
  

  Giving vs. receiving oral sex

  
  

  Giving oral sex (your mouth being on the partner’s genitals) is a bit riskier than receiving it (your partner’s mouth being on your genitals). This is due to the possibility of having small cuts in your mouth and not being aware of them. In addition, your partner’s fluids can come into contact with your mouth and throat.

  
  

  Mouth-to-penis vs. mouth-to-vagina vs. mouth-to-anus

  • Mouth-to-penis sex is considered a bit riskier than mouth-to-vagina sex.
  • Mouth-to-anus sex is considered to be very low risk for HIV; there is a greater chance of getting a bacterial infection than of getting HIV

• What should I know about HIV transmission through rectal sex (giving and receiving)

  Anal sex is one of the most common ways of getting HIV. This is because the lining of the rectum is very thin, which makes it easier for HIV to enter the body there.

  
  

  Receptive anal sex (receiving a penis into the rectum) is 13 times riskier than insertive anal sex (inserting the penis into the anus).

  • Receptive anal sex: 1.4% chance of contracting HIV regardless of gender
  • Insertive anal sex: 0.11% or 0.062% of contracting HIV (circumcised or uncircumcised, respectively)

• How soon after contracting HIV does a person become infectious?

  The HIV virus needs one to three days after contraction to replicate and can spread beyond the original entry site. So, the person is passing the infection before it can be detected in testing.

• Is it true that some people are more predisposed to getting HIV than others?

  Around 11% of people of African descent are predisposed to acquiring HIV infection. It is less common in other ethnic groups. This predisposition increases their chance of getting HIV by 40%. This is believed to be connected to a gene variant called Duffy antigen receptor for chemokines (DARC), which was well studied for another condition, malaria. DARC-negative individuals are more susceptible to HIV infection.

• What is the chance of natural HIV immunity?

  A very small proportion of the population (under 10%) has HIV resistance from birth. This is believed to be connected to a mutation of the gene encoding CCR5, which acts as a receptor for HIV.