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Some people say that holes in latex are large enough for the AIDS-causing HIV and chlamydia to pass through, so that condoms do not protect against these STDs. Others dispute this statement and consider condoms to be effective in blocking HIV transmission. What is the typical size of holes in latex and how does it compare to the size of viruses? Are viruses like HIV able to get through these holes?

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    The first time I came across this claim was in a brochure from some catholic organization. Who would have thought? :D – Lagerbaer May 13 '11 at 15:02
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    See also the Straight Dope. – Tim Pietzcker May 13 '11 at 15:14
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    only one hole, and something bigger goes through that. – Jodrell May 15 '11 at 9:24
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    Google or condom balloon site:youtube.com, and reflect that the oxygen and nitrogen molecules than make up air are much smaller than a virus. – dmckee Nov 30 '11 at 0:39
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    @dmckee Well helium balloons remain inflated for quite some time too, but that doesn't mean they aren't leaking at a rather significant rate. So that evidence is not too convincing... – RomanSt Dec 5 '11 at 19:54
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Concerning the question of whether the HIV virus can pass through condoms, the answer appears to depends on the type and condition of the condom.

The first question is, what kind of condoms? It seems that the available internet literature readily acknowledges that:

“Condoms manufactured from latex are the most popular, and studies conducted on the ability of condoms to prevent the transmission of STDs and HIV most often involve latex condoms. Condoms manufactured from lambskin, also known as "natural skin," or "natural membrane," are made from the intestinal lining of lambs. While these condoms can prevent pregnancy, they contain small pores that may permit passage of some STDs, including HIV, the hepatitis B virus, and the herpes simplex virus.”

These kinds of condoms were not widely available at one time. Users would be well advised to recognize this point in making their condom selection if the interest is to avoid the transmission of sexually transmitted diseases (“STD”s), including AIDS.

Incidentally, presumably, natural membrane condoms presumably make dandy water balloons. Likewise, rubber gloves are “water tight” but HIV can pass through the pores in rubber gloves, which is why the latex used for condoms is manufactured to more rigorous specifications. According to Straight Dope:

I'll say. Your clip is a 1992 letter to the editor from Mike Roland, editor of Rubber Chemistry and Technology, a publication of the American Chemical Society. Roland argued that "the rubber comprising latex condoms has intrinsic voids [pores] about 5 microns (0.00002 inches) in size. Since this is roughly 10 times smaller than sperm, the latter are effectively blocked.... Contrarily, the AIDS virus is only 0.1 micron (4 millionths of an inch) in size. Since this is a factor of 50 smaller than the voids inherent in rubber, the virus can readily pass through."

This sounds scary, but there are a couple problems with it. First, Roland bases his statement about a 5 micron latex pore size on a study of rubber gloves, not condoms. The U.S. Public Health Service says that condoms are manufactured to higher standards than gloves. Condoms are dipped in the latex twice, gloves only once. If just 4 out of 1,000 condoms fail the leak test, the whole batch is rejected; the standard for gloves is 40 out of 1,000. A study of latex condoms by the National Institutes of Health using an electron microscope found no holes at a magnification of 2000.

This seems to be the an article on the original report on holes in latex gloves.

So, the point that HIV molecules are larger than water is a “red herring” with respect to determining whether condoms are useful to preventing the transmission of HIV.

Second, and a more precise question is, can HIV pass through latex condoms?

As the Straight Dope quote indicates, there was an FDA report indicating that under extreme test conditions – certainly unlikely to replicated in actual performance - HIV viruses were found to have passed through latex condoms.

Internet literature from AIDS information sites - that do not seem to have an "anti-condom" agenda - seem to agree that the “pores” in latex condoms are approximately .5 microns in size, whereas the HIV virus size is .1 microns. See this Arizona health site for corroboration.

There seems to be some dispute as to whether infection can occur through the virus alone. According to Straight Dope:

As for the substantive issue you raise, it's true "the transmission of HIV by genital fluids most probably occurs through virus-infected cells since they can be present in larger numbers than free virus in the body fluids" (Jay Levy, "Pathogenesis of Human Immunodeficiency Virus Infection," Microbiological Reviews, March 1993--an exhaustive treatment of the subject). But it would be wrong to construe this to mean that HIV is transmitted only by cells. When I spoke to Dr. Levy he readily conceded that HIV may be transmitted by free virus as well. He did add that the viscosity of semen may hinder the passage of such virus through the latex barrier.

If this information is outdated it would be nice to know.

A lot of internet sources quote the “factoid” that condoms have “pores” of .5 microns in size. I suspect from my efforts to chase down the source of this information that it may come from the 1992 report based on an examination of latex gloves noted above. This site directly addresses the “pore hypothesis” and concludes that the double layers of latex in condoms prevents the formation of holes or pores that go through the entire condoms. That seems to be the best explanation for the anomaly of HIV not passing through condoms like "bullets through a netting."

So, the answer seems to be that outside of artificially created circumstances and assuming properly manufactured, non-defective, non-deteriorated condoms, the HIV virus will not pass through latex condoms.

Third, an even more precise question, is whether HIV can pass through condoms under ordinary usage?

A caveat to arguments about the effectiveness of condoms is always that they have to be used properly and invariably. Proper usage involves more than mechanics. Health sites often contain warnings that deterioration, and opening up condom practices with teeth or nails, can introduce tears into the condoms. For example, Health Communities.com states:

Condoms should be purchased from a source that can guarantee product reliability and freshness. Heat, pressure, and age can break down latex. Condoms should not be used more than 5 years after the manufacture date. If the condom looks deteriorated or discolored, or feels sticky or brittle, it should be discarded. If the packaging is torn or damaged, the condoms should not be used.

Condoms are easily torn if they are handled roughly or with sharp fingernails, so care should be taken while putting them on and taking them off. Petroleum or oil-based lubricants (e.g., Vaseline, baby oil) can break down latex and should not be used. Water-based lubricants (e.g., KY Jelly) should be used and are usually labeled "For use with latex condoms or diaphragms."

Hence, fresh out of the box condoms provide a level of protection that may not be found in one left in a wallet or the glove compartment.

Fourth, even if all things go right, are condoms always effective?

The answer is clearly “no,” as suggested by the 4 out of 1,000 flaw rate mentioned above.

According to this site:

Generally, the condom's effectiveness at preventing HIV transmission is estimated to be 87%, but it may be as low as 60% or as high as 96%. Conclusions: Consistent use of condoms provides protection from HIV. The level of protection approximates 87%, with a range depending upon the incidence among condom nonusers. Thus, the condom's efficacy at reducing heterosexual transmission may be comparable to or slightly lower than its effectiveness at preventing pregnancy. Family Planning Perspectives, 1999, 31(6):272-279

Condoms are clearly effective in decreasing the odds of being infected, but, clearly they are not absolutely effective. It appears, though, that the risk of infection from an HIV viruses making its way through a non-defective, non-compromised condom is de minimis. One, however, should not be entirely sanguine about the effectiveness of condoms under all circumstances.

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    I analyzed the facts in the context of the ambiguities of the question. An answer that "condoms don't have holes large enough to allow the passage of HIV" is clearly overbroad in that "natural skin" condoms do. Likewise, insofar as quite ordinary conditions - putting a condom in a wallet or a car glove compartment - could compromise condoms and allow the formation of holes large enough to permit transmission of HIV is also true. I didn't understand that being a "skeptic" meant being a cheerleader for the proposition that all one needs to avoid AIDS is a condom, because as you note, it's not. – Peter Sean Bradley May 16 '11 at 20:56
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enter image description here source

As nicely as I am willing to put this, the idea that condoms have pores in them large enough to allow the HIV virus to pass easily through is complete and utter nonsense which has likely caused the deaths of thousands, if not far more. It is peddled by those pushing a moral or social agenda and is blatantly contrary to the scientific evidence.

NOTE: For this answer, I am referring to Latex condoms only, not any of the other varieties

However, before answering I first double-checked the sources. On the vatican's website I found some of the same arguments..

“There are two types of efficacy that could be considered in particular. First, ‘technical’ efficacy: since when did the condom ‘prevent’ the risk of contamination? In scientific circles, it is openly admitted that condoms are in fact not 100% safe. On an average, it is said that there is a 10-15% inefficacy, since the AIDS viruses are much more ‘filtrating’ [able to pass through] than the sperm.13 Therefore, even at a ‘technical’ level of efficacy, one should question the scientific seriousness and the consequent professional seriousness of the condom campaign. There is a great risk involved: to ‘deceive’ persons by propagating ‘safe sex because one is protected’, while in fact it is not safe, or is not safe in the way it might be thought to be. The illusion becomes much more dangerous and serious when there is an even greater duty for persons ‘at risk’ or who indulge in promiscuous sexual relationships not to spread the infection (both to the partner and, eventually, to present or future children).’” source

The failure rate of condoms mentioned here is largely due to inconsistent or incorrect use, not due to inherent flaws, or "pores".

As regards the AIDS plague, it is
reemphasized that the Church is in the front line of the struggle against the virus and in treating its victims, and that the question will not be resolved by handing out condoms.source

This seems to be a fairly succint statement of their thoughts on the matter. In a sense, they are correct, condoms alone will not stop the spread of HIV-AIDS, but nearly every single study shows that it will greatly slow the rate of transfer.

However, perhaps acknowledging the severity of the problem (death total in the millions worldwide), the church does admit:

Given that AIDS is a serious threat, any inadequate information based on
false security offered by condoms used as prophylactics would be a grave
irresponsibility source

The same document goes on to say:

This means that the safe sex Russian Roulette becomes even more serious with repeated condom use.source

Apparently clarifying what they consider to be adequate information.

ON THE OTHER HAND..

One of many studies done on the spread of HIV explains that moral/religious reasons are most often given as the reason for not only refusal to use condoms but for a refusal to teach others how to appropriately use condoms:

Differences were observed across settings in the prominence accorded to condoms, the assessment of their effectiveness, and certain barriers to and facilitators of their use. Moralization emerged as a key impediment to positive representations of condoms source

THE SCIENCE...

The Catholic church's argument may or may not be based on the following quote:

"the rubber comprising latex condoms has intrinsic voids [pores] about 5 microns (0.00002 inches) in size. Since this is roughly 10 times smaller than sperm, the latter are effectively blocked.... Contrarily, the AIDS virus is only 0.1 micron (4 millionths of an inch) in size. Since this is a factor of 50 smaller than the voids inherent in rubber, the virus can readily pass through." - Editor of Rubber Chemistry and Technology, Dr. C. Michael Roland of the U.S. Naval Research Laboratory in Washington D.C

However, there are a few problems with this reasoning..

  1. size of water molecule is .278nm
  2. electron microscopy of HIV virion shows an average size of 120-200nm

If water molecules, which are smaller do not leak through latex condoms, the larger HIV virion will not pass through.

study confirms this with leak testing:

11 condoms with leak rates were nl/s vs. 6 condoms with leak rates 1-9 nl/s (p .002). The widely used 300 ml water test did not indicate any pores in any of the condoms. In the extreme and highly unlikely scenario of all the fluid being pumped out of the condom, the transfer rate would be about 0.1 mcl after 10 minutes of thrusting after ejaculation filled the condom with semen (i.e., 0.01% of a typical 3 ml ejaculate). Thus proper use of latex condoms would result in exposure reduction from HIV of at least 4 orders of magnitude. These findings demonstrated that use of latex condoms can significantly reduce the risk of HIV transmission, but it does not eliminate that risk. source

Similar findings from the CDC

  1. Can HIV leak through microscopic holes in latex condoms?

    The Food and Drug Administration (FDA) published a study in the July-August 1992 issue of "STD" which examined whether HIV-sized glass beads could be forced through latex condoms under stressful laboratory conditions. These conditions included higher concentrations of the "virus" (glass beads) than in semen, a fluid that doesn't stick together as much as semen, and forces that simulated 10 minutes of thrusting AFTER ejaculation. Most latex condoms leaked absolutely nothing. The worst condom found would still reduce exposure risk by 10,000-fold, i.e., only 1 HIV virus might "leak" through only 1 of every 90 condoms. Other tests have shown that under "normal" conditions, HIV does not pass through a latex condom that is not torn or broken.

This is not because of surface tension or hydrogen bonding in water, it is because electron microscopy has shown that the "pores" or "holes" mentioned in the argument are not there not there to begin with.

Yet another problem with this reasoning is that Roland's information is based on a study of latex rubber gloves.

From Cecil Adams:

This sounds scary, but there are a couple problems with it. First, Roland bases his statement about a 5 micron latex pore size on a study of rubber gloves, not condoms. The U.S. Public Health Service says that condoms are manufactured to higher standards than gloves. Condoms are dipped in the latex twice, gloves only once. If just 4 out of 1,000 condoms fail the leak test, the whole batch is rejected; the standard for gloves is 40 out of 1,000. A study of latex condoms by the National Institutes of Health using an electron microscope found no holes at a magnification of 2000 source

The standards by which condoms must be manufactured are overseen by the World Health Organization under the International Male Natural Rubber Latex Condom Standard ISO 4074 and can be found here

As to the general safety of the latex condom, the CDC offers this information:

enter image description here

HIV infection is, by far, the most deadly STD, and considerably more scientific evidence exists regarding condom effectiveness for prevention of HIV infection than for other STDs. The body of research on the effectiveness of latex condoms in preventing sexual transmission of HIV is both comprehensive and conclusive. The ability of latex condoms to prevent transmission of HIV has been scientifically established in “real-life” studies of sexually active couples as well as in laboratory studies.

Laboratory studies have demonstrated that latex condoms provide an essentially impermeable barrier to particles the size of HIV.

Theoretical basis for protection. Latex condoms cover the penis and provide an effective barrier to exposure to secretions such as urethral and vaginal secretions, blocking the pathway of sexual transmission of HIV infection.

Epidemiologic studies that are conducted in real-life settings, where one partner is infected with HIV and the other partner is not, demonstrate that the consistent use of latex condoms provides a high degree of protection. source

Of course, condoms are not 100% effective, because nothing is, but Myron S. Cohen sums up the issue nicely in an academic context:

There is virtually no evidence to support the idea that knowledge or availability of condoms reduces rates of abstinence, or inspires promiscuity or riskier sexual behaviors. Condoms are clearly not perfect. They can be misused or (more rarely) fail or break. The benefits of condoms may not extend to protection from all STD pathogens, nor has their usage to prevent transmission of all STD pathogens been studied. However, the ability of condoms to prevent transmission of HIV is well established, and condoms must remain a first line of defense in any HIV prevention campaign - Protective Efficacy of Condoms? Myron S. Cohen, MD

However, for pure eloquence, Stephen Fry from the Intelligence Squared Debate(part2)

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    I think there's too much handwaving in this argument: "If water molecules, which are smaller do not leak through latex condoms, the larger HIV virion will not pass through." – user2721 May 14 '11 at 7:32
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    Why was it necessary to turn a question about the porosity of condoms into a diatribe against the Catholic Church? Was it necessary to the argument to tie the position that condoms are "porous" enough to allow HIV to pass through to the Catholic Church in order to give it more strength? – Peter Sean Bradley May 14 '11 at 17:03
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    @Peter Much as with the anti-vaccination movement, when dissemination of incorrect scientific evidence spreads sickness and death, as scientists (and as human beings) we have an ethical responsibility to take to task not only the claim itself, but those making it, as well as to do our very best to ameliorate the damage done and relieve the suffering of others. – Monkey Tuesday May 14 '11 at 21:42
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    The problem is that your answer sounds like it has an agenda which detracts from providing an answer that is "skeptical" of all myths and urban legends. – Peter Sean Bradley May 15 '11 at 6:31
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    @peter really, I thought, if anything readers would be bored by the sheer amount of substantiated facts I cited in my answer. – Monkey Tuesday May 15 '11 at 8:29

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