The U.S. reference and referral service for information on HIV/AIDS, viral hepatitis, sexually transmitted diseases (STDs), and tuberculosis (TB). NPIN is a next-generation clearinghouse that collects and disseminates data and materials to support the work of prevention organizations and workers in international, national, state, and local settings. Their services are designed to facilitate program collaboration in sharing information, resources, published materials, research, and trends among the four diseases.