Washington, D.C., has the highest HIV infection rate in the U.S. -- one in 20 residents are HIV-positive -- but a needle-exchange program is helping to save lives by preventing drug users from spreading the disease, the Associated Press reported Aug. 24.

D.C. was slow to adopt needle exchanges in part because Congress -- which controls the city's purse strings -- for decades refused to allow money to be spent on the harm-reduction initiative. However, the funding ban was lifted earlier this year.

"If you want to reduce the spread of HIV ... you put more syringes out there," said Ken Vail, executive director of PreventionWorks!, which now received some of the $700,000 being allocated for needle exchanges in the city.

An estimated 10,000 D.C. residents have contracted HIV by sharing dirty needles, and drug use is the second-leading cause of infection in the city after unsafe sex.