Professor Prabhat Jha of the University of Toronto's Dalla Lana School of Public Health and St. Michael's Hospital's Centre for Global Health Research examined the impact of prevention among female sex workers whose contact with male clients contributes substantially to new HIV infections in the general population.
The virus is then spread to the wives and other sex partners of these male clients, Jha said.
"We not only have to prevent human immunodeficiency virus, but also other infections like syphilis," lead author Paul Arora said in a statement. "Prevention among sex workers can reduce various infections, and prompt treatment of sexually transmitted infections is particularly important."
The prevention programs provided condoms and treated STDs among sex workers and their clients in addition to other activities.
The authors examined data from 868 prevention projects involving 500,000 female sex workers implemented from 1995-2008.
The study, published in the British Medical Journal Open, found the levels of HIV fell by 40 percent and the levels of syphilis fell by 70 percent among pregnant women between 2003 and 2008.