Condoms 101: Taking A Closer Look

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For three decades, condoms have been the mainstay of what we think of as safer sex. They don't just prevent HIV transmission, they also stop several other sexually transmitted infections (STIs) and prevent unwanted pregnancy.

Condoms can be found in a range of sizes and materials. As well as "male" condoms that go on a penis, there are "female" condoms that are worn by the receptive partner in vaginal or anal sex.

Condoms are (relatively) cheap and readily available. They are a simple and practical way to protect yourself and your partners if you only need protection from time to time.

Unlike newer prevention methods, no one needs to put a drug in their body. But condoms are not, in real world conditions, as effective in stopping HIV transmission as an HIV-positive person taking HIV treatment or an HIV-negative person taking pre-exposure prophylaxis (PrEP).

Laboratory studies do, however, show that condoms provide a highly effective physical barrier against even the smallest sexually transmitted pathogens. Bacteria and viruses (including HIV) cannot pass through latex, polyurethane, polyisoprene or nitrile -- the materials that condoms are made from. If an intact condom is in the right place throughout sexual intercourse, HIV won't be passed on.

Both male and female condoms provide a barrier between a body fluid containing HIV and the mucous membrane of another person. Mucous membranes are those moist body tissues that are susceptible to HIV infection -- the foreskin and urethra of the penis, the vagina and cervix, the anus and rectum.

Other Sexually Transmitted Infections?

Condoms can also provide substantial protection against a number of other STIs besides HIV. How much protection depends on how the STI is transmitted.

Gonorrhea, chlamydia and trichomoniasis are -- like HIV -- infections in body fluids (such as a genital discharge or genital secretions), so a condom will provide a high level of protection.

But if a sexually transmitted infection is transmitted through skin-to-skin contact, a condom cannot provide as much protection. STIs that are passed on by skin-to-skin contact include genital herpes, syphilis, genital warts, anal warts and chancroid.

For these infections, condoms will only be effective if they prevent contact with the skin, sores or ulcers that are infectious. However, frequently they will do so -- for example, a male condom will cover a sore on a penis.

Female condoms have an advantage here, as they cover a greater surface area, including both the internal and external female genitalia.

Nonetheless, a condom may not cover other or all infectious skin.

In considering condoms and STIs, it's also important to remember oral sex. Many STIs are much more easily transmitted during oral sex than HIV is. If you use condoms for vaginal or anal intercourse only, you could still pick up an STI during oral sex.

Although condoms can't prevent all cases of STI transmission, they do provide a substantial level of protection. People who use them consistently get far fewer cases of STIs (especially chlamydia and gonorrhea) than other people.

Putting Things Into Practice

Using condoms is not just a question of having a technical understanding of them. They need to be remembered and put on at the time of having sex, in the heat of the moment. If you treat putting on the condom as part of the foreplay, rather than as an interruption of it, things may well be easier. With plenty of practice, many people find that condom use becomes an integral part of sex.

But it takes two to tango: How you and your sexual partner interact will be crucial to whether a condom is used. Rather than it just coming down to you or the other person, the way the two of you communicate is what matters. Not all of that communication will be verbal.

In many situations, both partners will want protection to be used, and it will be reassuring for both to see that a condom is in place. But in other situations, this will be tricky. You may want to use protection, but your partner may be unconvinced, uninterested or hostile.

This can especially be a problem as you get to know a partner. Newly formed couples often find that it's harder to continue using condoms as their relationship develops -- the growing feeling of trust may make one or both partners feel that condoms aren't necessary. This may be despite no up-front discussion about HIV status and how recently each person tested. Thus, the risk may be as great as the first day you met.

Using Them Properly

Another reality of using condoms is that, on occasion, they break or come off. Research suggest that this can happen around 2.5% of the time.

Condoms are more likely to break, leak or come off if they are used incorrectly. And studies show that incorrect usage is quite common.

But condom failure happens to some people far more than it does to others. That shows that by learning the right way to use condoms and getting plenty of practice, it is possible to have a far lower failure rate.

Some things that people do wrong with male condoms include using condoms that are too small or too large for them, unrolling condoms before putting them on, using sharp objects to open condom packages, not using enough lubrication and letting the penis go soft before pulling out. Also, it may be that a person cannot maintain an erection while using a male condom -- so in that case, it's not that they've doing something wrong -- and using a female condom in the insertive partner can be helpful as an alternative strategy.

Another important reason for condom failure is not using a condom throughout penetrative sex. Putting one on after penetration has begun or taking it off before you have finished could allow an infection to be passed on. Pre-cum, the fluid that may be produced before ejaculation, can carry infections. Equally, an uncovered penis could be exposed to an infection in the receptive partner.

You can find step-by-step instructions on using a male condom here.

"Female" condoms work in a different way and have their own instructions. One of the key points is to make sure that the penis goes inside the condom -- it should not slip in between the condom and the side of the vagina.

Different Materials, Different Sizes

There is a wide range of condoms out there. While most male condoms are made from latex, some people have an allergy or sensitivity to this type of rubber. If that's the case, try a condom made from polyurethane or polyisoprene.

You may find that condoms from these materials have other advantages -- they are thinner and transmit heat better, making sex feel more natural. They don't have the same smell as latex condoms. But some polyurethane or polyisoprene condoms marketed as being especially thin may be more likely to break.

Another important difference is that polyurethane products are the only male condoms that can be used with an oil-based lubricant (such as Vaseline). Male condoms from other materials should only be used with a water-based or silicone-based lube.

You might also see male condoms made from a thin membrane of sheep intestine, called lambskin condoms. They can prevent pregnancy but are not recommended to prevent HIV or STIs. Viruses and bacteria can pass through the membrane.

You can obtain male condoms in a range of sizes. If you feel that condoms are too tight, too loose or too short, try to find a size that suits you better. Condoms should be tight enough that they aren't easily pulled off, but not uncomfortable or so tight they tear. Ill-fitting condoms make it harder for some men to maintain an erection. Specialized online retailers are good places to find a range of sizes.

Female Condoms: Not Just for Women

Although other female condoms are available in other countries, there is just one brand approved by the U.S. Food and Drug Administration and sold in the United States. Called the FC2, it is an improvement on the original model introduced in the 1990s. As it is made from nitrile, it has a softer feel and makes less noise. You can use oil-based lubricants with it.

At first the look and feel of female condoms can be surprising -- it's worth practicing the insertion method before having sex and also trying them a few times before deciding whether you like them or not. Couples who find male condoms uncomfortable or difficult may find that they prefer female condoms for either vaginal or anal sex.

How Effective Are Condoms?

HIV cannot pass through an intact condom. So, if a condom is used correctly from the beginning of intercourse to the end and does not break, it will prevent HIV from being passed on.

But things aren't always as clear-cut in real life. The mistakes that people make when using condoms increase the chances of one splitting or coming off. This could allow HIV to be passed on.

In fact, when researchers have recruited HIV-negative people with HIV-positive sexual partners and compared the HIV infection rates in those who use condoms with those who don't, the reported effectiveness is quite a way off 100%.

This is an inherently tricky subject to research. Scientists have to rely on what people say about their sexual behavior (as not many of us would agree to having a scientist observe us in the bedroom), but the information given is somewhat unreliable. Study participants probably don't admit to all instances of sex without condom. They may not report condom breakages. Both these points will skew study findings.

But the U.S. Centers for Disease Control and Prevention (CDC) estimate that using a male condom during anal or vaginal sex reduces the risk of HIV transmission around three- to five-fold.

Condoms' protective effect is substantial -- but not as great as that of HIV-negative people using PrEP (a 10- to 13-fold reduction in risk) or HIV-positive people having an undetectable viral load (a 25-fold reduction in risk).

Even greater levels of protection are seen when two prevention methods are combined. If both PrEP and condoms are used, sex is about 50 times less risky than with no form of protection. With both an undetectable viral load and condoms, anal sex is 89 times less risky and vaginal sex is 125 times less risky.

To take a closer look at these estimates, check out the CDC's Risk Reduction Tool. This online calculator can give you estimates for the risk of HIV being passed on in specific scenarios.

Are Condoms Needed If You're Using PrEP or HIV treatment?

The science of HIV prevention has advanced greatly in the last few years, and this has revolutionized many people's experience of safer sex.

We now know that HIV-positive people who are taking HIV treatment and have an undetectable viral load are highly unlikely to pass on HIV. And HIV-negative people can take antiretroviral medications as PrEP, making them highly unlikely to acquire HIV. Both methods are reliable so long as people take their pills consistently.

Many people want to know whether they still need to use condoms if one of these other prevention methods is in place. You'll find that many doctors and public health officials will offer quite cautious advice on this point, especially in relation to PrEP.

One reason for this is because, participants have always been advised to use condoms too when PrEP has been researched. So that means so far there is no scientific evidence assessing PrEP users' protection from HIV when condoms are not used -- even though we know not everyone in the research studies used condoms along with PrEP.

The situation is a little different for undetectable viral load. The PARTNER study specifically recruited couples who weren't using condoms before they entered the study. It showed that HIV-positive people with an undetectable viral load don't pass on HIV.

The other reason that doctors and public health officials may continue to encourage condom use is that they are not only thinking about HIV. Rates of STIs are already high in many communities and would be higher still if fewer people used condoms. Especially if you have multiple partners, there is a good chance of being exposed to a range of STIs.

While many STIs are easily treatable with prescription antibiotics, this is not always the case. It is becoming harder to treat some STIs because of drug resistance (for example, gonorrhea), viral infections are usually life-long (for example, herpes) and the treatment for some infections is complex (for example, hepatitis C). If left untreated, many STIs have serious consequences, including syphilis, chlamydia in women, hepatitis C and lymphogranuloma venereum (LGV).

While PrEP and an undetectable viral load can only protect against HIV, condoms also protect against STIs -- and unwanted pregnancy. It's worth considering your sexual health in a holistic way rather than focusing on only one infection. Your choices should depend on your personal circumstances and priorities.

But just focusing on HIV prevention for a moment, are condoms needed alongside antiretroviral-based prevention methods? If you are taking PrEP or HIV treatment, then you can take reassurance from the CDC's estimates showing that these methods are more effective than condoms alone.

But if you want to have an even greater level of protection, then using condoms in addition may feel more comfortable for you.

What if a partner tells you that he or she is on PrEP or HIV treatment, and so condoms are unnecessary?

The issue here is the degree to which you can be confident about what you have been told. If you know all about your partner's medication adherence, then that's one thing. But, in other situations it might be prudent to take your own measures to protect your own health.

Finally, the advantages and benefits of PrEP and HIV treatment shouldn't make us forget condoms' qualities.

Condoms are relatively cheap and easy to get ahold of. They don't require you to have good insurance, to be under the care of a physician or to take medication on an on-going basis. They make sense for people who don't have sex frequently or who need protection only from time to time. And condoms protect both partners from a range of sexual health problems.