HIV infection among non-injecting drug users doubled over the last two decades, a study has found. HIV and its transmission has long been associated with injecting drug use, where hypodermic syringes are used to administer illicit drugs. Now, a newly reported study shows that HIV infection among heterosexual non-injecting drug users (no hypodermic syringe is used; drugs are taken orally or nasally) in New York City has now surpassed HIV infection among persons who inject drugs.