How Can You Prevent an HIV Infection?

Medically Reviewed by Poonam Sachdev on April 30, 2022
4 min read

More than 1 in 5 young adults between the ages of 18-30 are concerned that they’re at risk for HIV. You may be especially worried if you have recently had unprotected sex with someone who tested HIV positive.

Sometimes, the danger isn’t as great as it seems. A woman who has unprotected vaginal sex with an HIV-positive man, for example, has only an 8 in 10,000 chance for each encounter. But if they have unprotected anal intercourse, their odds become much higher. Other things like sharing needles also increase the danger. But if you take a sip from the same glass as someone who has HIV, there’s virtually no risk.

Here’s what you need to know to protect yourself:

If you know or live with someone with HIV, you don’t need to worry about getting the virus through day-to-day contact. You can hug them, shake their hand, use the same toilet, drink from the same glass, or even kiss them on the mouth without worry. While HIV spreads through blood and body fluids like semen, this doesn’t happen with saliva. You also can’t get HIV if you eat a meal made by someone who’s HIV positive. Even if small amounts of HIV-infected blood got in the food, the virus can’t survive long outside a body, and your stomach acid would destroy it.

It’s best not to share the same toothbrush or to eat food that’s been already chewed by someone with HIV. Although very rare, there have been reports of infection in both cases. This is because if there’s any blood in the infected person’s mouth, it can enter yours if you have an open wound.

Condoms are the best way to prevent HIV because the virus can't pass through the barrier. But you must use them correctly each and every time you have sex. Latex condoms give you the best protection. If you’re allergic to them, use polyurethane (plastic) or polyisoprene (synthetic rubber) ones. Stay away from condoms with a natural membrane like lambskin. They have small holes in them, so they can’t block HIV.

Use a water- or silicone-based lubricant to lessen the chance that a condom will break during sex. Don’t use oil-based lubricants like Vaseline or mineral or massage oils. They can weaken the condom and make it more likely to break.

It’s not likely that you’ll get HIV from giving oral sex to your partner unless you have an open sore in your mouth, like an ulcer or a bleeding gum. But to be safe, have your partner use a condom or dental dam -- a thin, square piece of latex or silicone that is placed over your partner’s vulva or anus when you have oral sex.

You’re at high risk for HIV if you share needles or syringes with others. The safest thing to do is to not share needles. Use only new, sterile needles. Some drugstores even sell them without a prescription. If you can’t get fresh needles, you can clean used needles with bleach, but you still have a chance of getting HIV from them. Though injected illegal drugs are the most dangerous, any type of recreational drug use can raise your risk. This is because they lower your inhibitions and make it more likely you’ll have unprotected sex. This raises your chances of getting HIV. If you do use drugs, always carry condoms.

You may be in a situation that makes you more likely to get HIV. You may share needles, or you’re in a relationship with someone who’s HIV-positive. If your partner takes HIV medication and has undetectable virus, they are unlikely to give it to you. But you may be at risk if they don’t take their medication consistently or don’t know what their viral load is.

You can protect yourself by taking a daily pill to help avoid infection. It’s called pre-exposure prophylaxis, or PrEP.  There are a few options. The pill, Truvada contains two drugs, emtricitabine and tenofovir. These are antiretrovirals, which means they don’t allow the virus to take hold and spread through your body.

If you have unprotected sex with someone who’s HIV positive, your chance of getting HIV drops by about 99% if you take PrEP daily. It doesn’t work as well if you inject drugs, but it still lowers your chances by at least 74%. For it to work this well, you need to take it every day. 

A similar drug, Descovy, is approved for PrEP, but it’s not recommended for women having receptive vaginal sex. 

The medication cabotegravir (Apretude, Vocabria) are more recent approvals. Vocabria is also taken in pill form. Apretude is is given first as two initiation injections administered one month apart, and then every two months thereafter. It has proven to be 90% effective.

If you want to take PrEP, talk to your doctor. You’ll need to take an HIV test first to make sure that you don’t already have the virus. You’ll need to have tests every 3 months while on this medication. Many health insurance plans cover it. If you don’t have insurance, your doctor can help you find a medication assistance plan.