Dear Editor:

Re: Condoms Give A False Sense Of Protection Against Disease -- June 16.

Columnist Harriet Mostert writes that "HIV/AIDS carries a 15 per cent
risk of transmission even with a condom." For readers with mathematical
or scientific training, this claim should set off warning bells.
Fifteen per cent of what? Per encounter, per person, per year -- what
are the units?

She recommends the report
http://www3.niaid.nih.gov/research/topics/STI/PDF/condomreport.pdf .
Reading it explains Mostert's confusion. The report cites a study by
Davis and Weller that using a condom reduces the risk of HIV
transmission by 85 per cent. The key term here is "reduction of risk."
The 85 per cent figure does not refer to a "risk of transmission," but
rather the relative effectiveness of condom use with an HIV-infected
partner, versus not using a condom at all.

In fact, according to my reading of the report, Davis and Weller found
that using a condom with an HIV-infected partner resulted in less than
one infection per 100 person-years. When one considers that only 0.2
per cent of Canadians are HIV-positive, the expected rate of infection
for the average person drops even further.

I agree with Mostert that knowledge is essential in making health life
choices. Unfortunately she's miseducating, not educating.

Jeffrey Shallit