Advocates in South Africa fear that an increased demand for sex workers during this year’s World Cup, which will take place from June 11 to July 11, will lead to a rise in new HIV infections, CNN reports.

“And where there’s demand, there will be a supply,” said Eric Harper, director of the Sex Worker Education and Advocacy Taskforce (SWEAT) in Cape Town. “It could be a potential recipe for disaster both for the clients and the sex workers.”

The World Cup is expected to draw up to half a million soccer fans to South Africa, where as many as half of sex workers are already HIV positive. While no concrete data exist on the actual number of sex workers in the country, SWEAT estimates 3,000 work in Cape Town alone.

Harper argues that one of the chief reasons why sex workers—and, in turn, their clients—are at risk for HIV is that criminalization of their trade drives sex workers underground, making it difficult to educate them about HIV.

South Africa’s law against sex work might be reconsidered in 2011, when South Africa’s Law Reform Commission is expected to make recommendations to the Minister of Justice, but Harper argued that decriminalizing it for the duration of the World Cup this summer might prove beneficial.

However, health officials such as Julian Seedat of the South African National AIDS Council—which advises the government on its HIV/AIDS response—do not believe the World Cup poses a significant HIV risk.

“Over the years there has been an incredible amount of education and awareness work done among sex workers,” Seedat said. “Years ago, the high-risk groups were thought to be homosexuals and sex workers, but there has been such a focus on education for these groups that their behavior has really changed. It’s quite the norm for a commercial sex worker to have a bag full of condoms.”