Protecting UACs Through Enhanced Sponsor Vetting Act of 2021 This bill requires the Office of Refugee Resettlement within the Department of Health and Human Services to take additional actions when placing an unaccompanied alien child in the custody of a sponsor. Before placing such a child with a sponsor and again when a placement decision has been made, the office must notify the governments of the state and the locality in which the prospective or selected sponsor resides. When making determinations concerning the placement of such a child with a sponsor, the office must (1) include the Federal Bureau of Investigation and appropriate state and local law enforcement in its consultations, (2) ensure that the child is protected from designated transnational criminal organizations, (3) conduct a thorough background check of each prospective sponsor using the Next Generation Identification System, and (4) share with the Terrorist Screening Center any information establishing the child's or sponsor's affiliation with a designated transnational criminal organization.