In summary, needle exchange programs are operated from a variety of locations, some mobile, some fixed, and some with both fixed and mobile sites. Sites range from health department pharmacies to mobile vans to tables set up on city sidewalks.

The plurality of the programs are staffed by a combination of paid employees and volunteers. As with funding, the staffing mix is related to whether exchanges are legally authorized and the administering body of the programs. Programs administered by activists are typically staffed by volunteers. Only legally authorized programs that are administered by either local or state government agencies or community-based organizations are predominantly operated by paid staff.

According to Lurie et al. (1993a), needle exchange policies restrict the exchange of syringes, or limit eligibility to use the needle exchange programs, or both. These policies alleviate potential staff-participant conflicts by clearly delineating procedural rules that must be followed. In general, the policies seek to establish an optimal balance among the following criteria: remaining convenient to the participant, maintaining frequent contact with the participant, and alleviating community concerns over the potential of needle exchange programs to facilitate drug use or increase the numbers of needles discarded in public places.

At a one-for-one exchange, a new syringe is given out for each used syringe turned in. A needle exchange program that adheres to a strict one-for-one exchange rule cannot increase the total number of discarded syringes if it provides no starter needles. Starter needles are those distributed to participants at their first visits, even if they do not have any needles to exchange. This rule removes a potential barrier to entering a needle exchange program. The Lurie et al. (1993a) report classified needle exchange programs that give out starter needles but thereafter have a strict one-for-one exchange rule as having both rules.

An exchange maximum is a limit placed on the number of needles that can be exchanged per visit or per unit time. Some needle exchange programs impose an exchange maximum solely because of limited supplies. An argument sometimes offered in favor of an exchange maximum is that it brings participants back to the needle exchange program more frequently, thus increasing staff-participant contact and providing more opportunities to refer injection drug users to drug treatment and other public health services. However, an exchange maximum might lead to an increase in the reuse of