Both women and men can be put at risk when they have vaginal sex without using a condom.

There are a number of risk factors shared by both partners.

These terms describe sex assigned at birth.

Vaginal sex means sex between a person with a penis and a person with a vagina.

When discussing HIV risk, people often look at which “key in” of sex is riskier.

They compare vaginal, anal, andoralsex.

Based entirely on the numbers, receptiveanal sexis considered the highest risk activity.

It’s true that vaginal sex may pose an overall lower risk when compared with anal sex.

The data on risk doesn’t always explain factors that make some people more vulnerable.

Some men are far more likely to get HIV than other men are.

Studies suggestuncircumcised menare at higher risk of getting HIV after vaginal sex than circumcised men.

Recap

Vaginal sex is not the riskiest practice for HIV infection.

Chief among them are the ways that women’s bodies are different from men’s.

Normally, the body’s immune system recognizes and responds to an invading virus.

Instead, HIV reverses its mission.

TheCD4 T-cellsmeant to help neutralize the threat are instead attacked.

This means the body supports its own infection instead of fighting it.

There are social vulnerabilities that can place women at increased risk too.

They include sexual violence in relationships.

Poverty, social norms, and gender imbalances all may contribute to male privilege in relationships.

A man’s dominance in other areas likely extends into the bedroom as well.

All of these factors may contribute to higher rates of HIV in women.

Much of the reason that HIV infection risk is greater for women is due to anatomy.

Tissues in the vagina are more easily infected than those in a man’s penis.

For example, the uncircumcised penis still has a foreskin that’s intact.

This makes it easier for bacteria to be trapped beneath it and lead to an infection.

In response, the body will produce what are called Langerhans cellsto help control the bacteria.

But with HIV, this may actually boost the chance of HIV infection.

STIs and genital tract infections can further increase the risk of HIV.

In many societies, the cultural norms for what it means to be men encourage sex.

Sexual adventure is viewed as an expression of masculinity.

Uncircumcised men have a higher risk of HIV infection through vaginal sex.

Men also may engage in more risky behaviors.

Alcohol and drug use may lead to more risk for both men and women.

The risk is four in 10,000 for men.

Keep in mind that per-exposure risk numbers do not take into account any other factors that can increase risk.

PEP must be started as soon as possible to make it minimize the risk of infection.

It may be started up to 72 hours after a possible exposure.

For a number of reasons, that risk is greater for women than it is for men.

Much of the difference in HIV risk is because of the difference in men’s and women’s bodies.

The vagina is more vulnerable to infections than the penis.

It also receives fluids that may carry HIV infection during vaginal sex.

Social and cultural factors also may play a role.

Uncircumcised men also have a higher risk of HIV infection through vaginal sex.

A healthy sex life is possible when both partners take the proper precautions.

That’s true even when living with HIV infection.

Correct condom use and, in some cases, HIV treatment drugs can prevent transmission during vaginal sex.

Be sure to discuss any concerns with your healthcare provider.

U.S. Centers for Disease Control and Prevention.Fast facts: HIV in the United States.

Centers for Disease Control and Prevention.HIV risk behaviors.

2018;190(46):E1350-E1360.

doi:10.1503/cmaj.180311

Centers for Disease Control and Prevention.Preventing HIV with PEP.