Merlin Beach

I refer to Dr Hui Keem Peng’s letter (Dec 4 2004 Today) Condom Myth is No tall Tale.
In the 2001 report by the United States’ National Institute for Health that Dr Hui mentioned, it is stated:
“Condom usage was classified into the following three categories: always (100% use), sometimes, and never. Among participants who reported always using condoms, the summary estimate of HIV/AIDS incidence from the twelve studies was 0.9 seroconversion per 100 person years. Among those who reported never using condoms, the summary estimate of HIV/AIDS incidence from the seven studies was 6.7 seroconversions per 100 person years. Overall, Davis and Weller estimated that condoms provided an 85% reduction in HIV/AIDS transmission risk when infection rates were compared in always versus never users.”
What this means is for every 100 couples (one of which is hiv+) having sex repeatedly through the course of a year, using condoms every time, only 0.9 persons sero-converted to HIV-positive.
This suggests that if you are HIV-negative, and with the consistent benefit of condoms, you had sex with an HIV-positive person over a 100-year period, your chance of being HIV-positive after 100 years would be 0.9%.
The 85% figure is arrived because the risk of HIV infection with a hiv+ person without benefit of condoms is not 100%.
If it were, the figure would be 99.1%.
Thus it can be clearly seen that anti choice radicals who consistently quote 85% figures are being scientifically illiterate or deceitful.
Yours Sincerely
Christopher Low
n.b.
(6.7 – 0.9)/6.7 * 100 = 85%
(100 – 0.9)/100 * 100 = 99.1%

*to clarify, an 85% risk reduction is not the same as saying something is 85% effective.