By the time police discovered the shipment of fake COVID-19 vaccines, the vials had travelled over 6,000 miles from China to South Africa, the work of a smuggling ring that has produced thousands of counterfeit doses, according to Interpol, the global police agency that helped break up the operation. The trafficking case, involving a shipment of at least 2,400 doses, is the first confirmed instance of fake vaccines being smuggled across continents, an Interpol spokesperson told TIME—though there are likely more that have occurred, and more still that may be uncovered in the future.