Stigma toward key populations at higher risk of HIV infection, such as persons who inject drugs (PWID) in Vietnam, is a major challenge in fighting HIV epidemics around the world. Fear of experiencing judgment, blame, and discrimination is a strong disincentive for key populations to get tested for HIV, to disclose their status to their partners, or to seek treatment and care. Results from a new study from the Johns Hopkins Bloomberg School of Public Health in Vietnam confirm that PWID are subject to dual stigma, both drug-related and HIV-related, and that different socioeconomic factors contribute to each of these types.Current thinking about stigma suggests that it could both cause and result from community-level social inequalities which cause differences in social or economic power, and cause social separation, differentiation and stereotyping between social groups. Other research has focused on how individuals' own socioeconomic status affects the level of stigma that they perceive or experience. The extent to which community-level inequalities and individual socioeconomic status contribute to the total perceived and experienced stigma is not well understood. To address these questions, the Hopkins research group used household surveys to collect data on stigma and socioeconomic status from more than 1500 PWID and more than 1300 community members in Thai Nguyen, Vietnam. The HIV epidemic in Vietnam is a mature epidemic concentrated in PWID and transmitted through unsafe injection practices. In 1993, the government of Vietnam pursued a campaign against "social evils," which targeted drug users and leveled blame for spreading HIV. Since 2006, advocates within the Ministry of Health have shifted toward a greater harm-reduction focus, however, high stigma toward PWID and HIV still exists. During the same period starting in 1986, economic liberalization under the policy of "Doi Moi" (renovation) has increased private commodity and landholding, international trade and investment, and rapid industrialization, all of which have widened income gaps and led to socioeconomic inequalities. This intersection of growing economic inequality and public reinforcement of stigmatizing attitudes provided a compelling context for research on the relationship between the two. The Hopkins researchers found that HIV-related stigma is higher in communities with higher inequalities in education, while drug-related stigma is slightly higher in communities with higher inequalities in income. The strongest findings, however, showed that both PWID and community individuals with higher educational attainment consistently reported lower levels of all types of stigma. Education was important to reducing stigma, and the benefits of education could override the socioeconomic inequalities in the community. The importance of education is not completely surprising, given similar findings in Tanzania, India, and elsewhere. Education may be acting as a proxy for HIV-specific knowledge, or may reflect broader social status within a community that values educational attainment. Another piece of the stigma puzzle was employment. PWID with only part-time work reported higher drug-related stigma compared to PWID who worked full time. Conversely, community members who were unemployed reported lower drug-related stigma compared to community members who worked full-time. Employment gives workers a feeling of contributing to the local economy, and feeling reciprocity and empathy when participating in the community. Unemployment or part-time employment may be simultaneously fueling resentment, separation and stigmatizing attitudes toward the unemployed and toward drug users in a similar way. Again, these strong individual employment effects persisted regardless of the socioeconomic inequalities of community they lived in. One of the most important implications of the findings is how each different type of stigma is affected by different types of socioeconomic factors or socioeconomic inequalities. This cautions against taking a broad-brush approach to stigma reduction programs and policies, such as focusing only on health education or only social development. It is especially important to recognize and target both drug-related stigma and HIV-related stigma in future interventions, addressing the most relevant social, economic and educational conditions that affect each type of stigma. Policymakers and public health practitioners should be mindful of the negative consequences associated with social inequality, such as increased stigma, and to ensure that neither HIV burden nor stigma are disproportionately affecting persons in lower social or economic strata.