 HIV education, HIV testing, condom use, and safer-sex negotiation greatly decreases the risk to the disease.Peer education as a harm reduction strategy has especially reduced the risk of HIV infection, such as in Chad, where this method was the most cost-effective per infection prevented.The threat of criminal repercussions drives sex-workers and injecting drug users to the margins of society, often resulting in high-risk behaviour, increasing the rate of overdose, infectious disease transmission, and violence.