The Prostitution Statistics You Have to Know claims that:
50% of prostitutes throughout the world have contracted the HIV virus
(For this statistic it references this BBC news article: The men who sleep with prostitutes)
Is this true?
It may be true or true-ish among some sub-populations.
THE PROSTITUTE PARADOX from 1993 says,
- In New York City, for example, 40 to 50 percent of streetwalkers (a very low caste of prostitute) who have used IV drugs over the past decade are HIV seropositive.
- Among call girls in New York City (a higher caste of prostitute), no seropositivity was found among those who were drug free. These figures were constant between 1984 and 1989.
- The same sorts of figures have been found in all Western nations.
It says that the risk factor is the using of intravenous drugs.
Two more data points:
List of countries by HIV/AIDS adult prevalence rate states than in a few countries (Lesotho, Botswana, and Swaziland) in Africa, the incidence is 25% in the general population of adults (it's 17% in South Africa), and I imagine it may be higher than that already-very-high average among any prostitutes there.
Perceived transmissibility of STIs: lack of differentiation between HIV and chlamydia claims (based on
Mastro TD, de Vincenzi I. Probabilities of sexual HIV-1 transmission. AIDS1996;10(Suppl A):S75–82.) that,
The estimated probability of HIV transmission from an infected heterosexual man to a woman in one act of unprotected vaginal intercourse is 0.1%
Probability of Heterosexual HIV-1 Transmission per Coital Act in Sub-Saharan Africa cites another study which says that 0.2% is a baseline: when the man is known to be HIV positive, and the rate of condom use is high (in the 78% to 93% range).
My guess is that 50% is too high to be a world average, especially in populations where HIV isn't pandemic.
However the maths says that infection rate of 0.3% implies a 50% chance of infection after 230 sex acts, when a condom is used more-or-less regularly, if all clients are HIV-positive.
If 10% of clients are HIV positive then the number is 2300 instead of 230.
According to this article published in the International Journal of Public Health by the Institute of Tropical Medicine, Antwerp, it's, on average significantly lower than 50%:
Funnily enough, this is actually the most recent chart I could find like this. I guess no one bothered to do another study in the last 25 years. However, there are a few more articles I found that give more recent percentages for certain areas.
Nigeria's growing commercial sex industry is a major source of human immunodeficiency virus (HIV) transmission, and studies undertaken in Lagos suggest that up to 20% of female prostitutes are HIV-infected.
But there is one more problem with the chart above, in that it only takes into account prostitutes that don't use intravenous drugs, and just assuming 0% in that field is just ludicrous.
According to one PubMed article, Human immunodeficiency virus seroprevalence and condom use among female sex workers in Italy, about 37% use intravenous drugs:
Overall, 131 of 802 (16%) were HIV positive: 36 of 558 (6%) professional sex workers and 95 of 244 (39%) sex workers who used intravenous drugs.
Sadly I can't personally find one specifically for the US. But, that said, based on the information above, I would hazard a guess that it would be significantly less than 50%