question ref statistics

[Patricius]

I am somewhat puzzled by statistics and apologies if i put this in the wrong place

If they refer to a 1 in 1000 possibility of contracting hiv from insertive vaginal intercourse  (it may be higher/lower )do they mean that a) in general population or b) with an infected indiviudal.

Eg if i live in country that has a population of 250 million people and 250,000 are hiv positive that means 1 in 1000.
So randomly going out into the general population, i have a 1 in 1000 risk of catching  hiv (ie entailing that any single exposure to an infected individual will guarantee I catch HIV) or is it 1 out of 1000 episodes with 1 positive person -ie out of 1 in 1000 people - ie 1000x1000, thus the absolute utmost outside odds are up to 1 in a million?

And probably less chance of a heterosexual male being exposed if say 50% of the infected persons are gay males?

[Teak]

Statistics are not used in accessing a risk. The only way for anyone to know if they have been exposed is by testing.

[joggen]

The 1 in 1000 statistic applies both to transmission during vaginal sex (1 out of 1000 exposures) assuming the partner is infected and there are no other risk factors, and the average prevalence in the heterosexual population in North America (1 out of 1000 people infected), again, assuming no other risk factors.

Thus, the estimated risk of one episode of vaginal sex to an unknown heterosexual partner is 1 in a million.

There are plenty of threads in the doctors forum that discuss this.