The altruism and/or solidarity of people who inject drugs helps protect sex and drug partners from HIV. Research has been hindered by lack of measures. We developed and administered scales to assess them to 300 people who inject drugs. Altruism and Solidarity Scales were both internally consistent. Each correlated significantly with measures of helping others. These measures appear reliable and valid. They can be used to study how big events or structural interventions affect altruism and solidarity, and how altruism and solidarity are associated with changes in HIV or other risks, among people who inject drugs.
Keywords: Altruism; HIV; big events; injection drug users (IDUs), people who inject drugs; measures; prevention; solidarity; structural interventions.