A new study discovered that a needle-exchange program in Washington, D.C. is in fact preventing hundreds of new HIV infections.

In 2007, there was a program that kicked off for injection drug users. Within only two years of the program beginning, it prevented an estimated 120 new cases of HIV infection and also saved about $44 million in HIV treatment costs. The findings from the study were published on September 3 in the journal AIDS and Behavior, according to CBS News.

“Our study adds to the evidence that needle-exchange programs not only work, but are cost-effective investments in the battle against HIV,” Monica Ruiz, of George Washington University in Washington, D.C., said in a university news release.

Ruiz is the assistant research professor at the university’s Milken Institute School of Public Health in the department of prevention and community health.

“We saw a 70mpercent drop in newly diagnosed HIV cases in just two years. At the same time, this program saved the District millions of dollars that would have been spent for treatment had those 120 persons been infected,” she said.

She also added that “the D.C. needle-exchange program continues to reduce the number of new cases of HIV among injection drug users in the city.”

The needle-exchange program was explained by the study authors as being relatively inexpensive at $650,000 a year and it provides injection drug users with an increased amount of access to clean needles. If they are in the program, they can also get an HIV test, free condoms and regular access to a source of health care. The program participants also were given the option of referrals for drug addiction treatment and tests that could help them to detect any other diseases commonly found among injection drug users such as hepatitis.

But in the face of all the positive things the program provides, critics continue to ridicule programs such as this claiming that it only encourages the use of illegal drugs.