It is easy to access sterile needles and syringes in urban areas of China because they are legally sold and available at pharmacies and medical clinics [16, 44] . However, many drug users live in rural areas; in addition, drug users may share needles and syringes because they can not buy them during night time or do not have money to buy them [16] . Methadone is orally administered, and metha-done substitution can reduce injection and needle sharing of opiate drug addicts. But methadone maintenance therapy is costly and requires drug users to attend clinics on a regular basis. Therefore, methadone substitution and needle exchange services should be made available and affordable at convenient times and in both urban and rural settings, especially in the communities with heavy drug use.