Shlemele:
Ok quick lesson in biology/science here. Viruses are very small. The HIV virus is so small that a molecule of water is several times larger than it…
This is not correct.
First, a definition of measurements.
A Meter (m) is about 39 inches, or a bit more than a yard (1.0 m)
A Micrometer (µm) is one millionth of a Meter (0.000,001 m)
A Nanometer (nm) is one billionth of a Meter (0.000,000,001 m)
A Picometer (pm) is one trillionth of a Meter (0.000,000,000,001 m)
A water molecule consists of three atoms only, one oxygen and two hydrogen, and is about 100 picometers (0.000,000,000,100 m) wide measured along one oxygen-hydrogen bond. Other ways of measuring can yield slightly longer or shorter widths or lengths, but not far from this ballpark figure. As molecules go, water is a very small molecule.
The HIV A and B viruses are much larger. These contain proteins that themselves are vastly larger than a water molecule as they may contain hundreds or thousands of atoms. In fact, the breakdown of one of these proteins into simpler proteins or amino acids might also result in the release of one or more water molecules as a by-product. I don’t know how many atoms there are in an entire HIV virus, but these viruses are about 120 nanometers (0.000,000,120 m), or to put them in the same measurements as used for thr water molecule, 120,000 picometers. This is over 1000 times the length/width of a water molecule and might be likened to a comparison between a giant redwood tree 300 feet tall and a blade of grass three inches tall.
This is not to say though, that we can not deduce something about the effectiveness of condoms against HIV. While an HIV virus is vastly larger than water molecule, it is also considerably smaller than a human spermatozoon, and as the failure rate of condoms with respect to pregnancies attests, condoms are not entirely effective in excluding objects the size of a human spermatozoon. Human spermatozoa consist of a head 5 µm by 3 µm and a tail 50 µm long. This means that in its narrowest dimension a human spermatozoon is 3,000,000 picometers, which is 25 times wider than an HIV virus, just in the spermatozoon’s smallest dimension (excluding the flagellum). This is like comparing a 6 foot tall man with a 2.8 inch tall mouse. We should not expect an opening that the man can walk through to be capable of keeping out the mouse.
Another consideration that should be kept in mind regarding condoms’ effectiveness against HIV is a woman’s monthly fertility cycle, as condom failure rate is measured in instances of pregnancy occuring in women using condoms as a contraceptive. Depending on the sources checked, the effectiveness of condoms against pregnancy is rated from 86% to 99.98%, which implies a failure rate of .02% to 14%. But this does not take into consideration the fact that most women are only capable of becoming pregnant from sexual intercourse on only about 25% percent of the days in their monthly cycle. If an actual condom “failure” occured at such an infertile time, meaning that the condom did not successfully prevent seminal fluid from entering the woman’s body, but no pregnancy occurred, this would not be factored as a condom failure.
As there is no reason to believe that there are naturally occuring times either in a man or a woman in which a person sexually exposed to HIV is significantly less likely to become infected, comparable to infertile times in which a woman is significantly less likely to become pregnant, this suggests that the failure rate for condoms regarding HIV infection might be expected to be as much as four times higher than the failure rate regarding pregnancy, or .08% to 56%. When considering that many women who use condoms might also use additional contraceptive methods that might prevent pregnancy even if an actual condom failure occur, this failure rate regarding HIV infection might be expected to be even higher.
