Can viruses pass through condoms?

Dear Dr. Eva,

I heard that HIV and other viruses can get through pores in latex condoms because viruses are so much smaller than sperm. Is that true?


Dear Wondering,

No, it isn’t true. Latex is a continuous solid surface. It has no pores – that’s what makes it so effective. Multiple scientific studies have shown that the HIV virus cannot pass through latex condoms. The condom is 100 percent effective unless it tears. When a condom is worn, infections can only be passed if the condom breaks, tears, or slips off. Tearing and breaking happen when condoms have been stored in a hot place, have passed the expiration date, or are worn too tightly with no space left at the end to hold ejaculate (cum). Don’t believe these myths. Wear a condom – it can save your life.

He’s finally undetectable – can we stop using condoms?

Dear Dr. Eva,

My partner is HIV positive. I am HIV negative. We are monogamous. Since the HIV virus is not detectable in his blood, is it safe for us to stop using condoms?

Discordant Pair

Dear Discordant,

It’s great that your partner is now undetectable. As long as he has no detectable virus, it is very unlikely that he will pass the HIV virus to you. There have been a few cases reported in which an undetectable person passed the virus on to a partner, but this is extremely rare. It’s up to you to decide whether a very small risk of infection is as good as no risk of infection (when you use condoms.)

If one is good, are two better?

Dear Dr. Eva,

Will wearing two condoms protect me better than one?

Double Safe

Dear DS,

Nope. Wearing two condoms is actually less effective than wearing one. If you wear more than one condom at a time, the condoms are more likely to break or slip off. This is true of wearing two “male” (penis) condoms at once or if wearing a “male” and a “female” (vaginal or anal) condom together. Use just one condom at a time, check the date to make sure it is not expired, and do not use it if it has been stored in a hot place like a glove compartment or a wallet.

How about now – it okay not to use a condom in this case?

Dear Dr. Eva,

Why do two HIV-positive people have to use condoms with each other?


Dear JD,

There are two reasons why it is dangerous for HIV positive people to be exposed to each other’s body fluids – especially semen, blood, and feces.

In the first place, because they are at greater risk for infection, people with HIV should avoid contact with anyone’s body fluids, whether the other person is HIV positive or not. Having HIV puts a person at greater risk for picking up sexual infections, including viruses such as herpes, HPV (the genital wart virus), and hepatitis; bacteria such as gonorrhea, chlamydia, and syphilis; and parasites like Giardia.

Secondly, a person infected with one strain of HIV can still become infected with other strains. This is uncommon, but when it occurs, viral resistance can develop, and disease progression to AIDS or death can occur much faster.

Follow-up question

Okay, what if one of the two people got HIV from the other? Then they have the same strain, so it should be okay, right?


Sorry, JD – it’s still not a good idea. The HIV virus mutates (changes) often. Every infected person carries multiple strains of the HIV virus. So you can get a second strain of infection from the partner who infected you in the first place. The HIV virus mutates (changes) very fast in a person’s body – so fast that the virus that a person became infected with, even a month ago, isn’t the same virus they are infected with today. t

Eva Hersh, MD, is a Baltimore family physician. Please send questions and comments to her by email at

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