Interpol, which unites nearly 200 police forces worldwide, said 400 vials of the counterfeits - equivalent to around 2,400 doses - were found at a warehouse in Germiston outside Johannesburg in South Africa.
Officers also recovered fake masks and arrested three Chinese and a Zambian national.
In China, police arrested 80 people and seized more than 3,000 fake vaccines after identifying a network selling counterfeit Covid-19 vaccines.
"While we welcome this result, this is only the tip of the iceberg when it comes to Covid-19 vaccine related crime," said Juergen Stock, Interpol's secretary general.
Networks
Last month Interpol issued an "Orange Notice" warning authorities worldwide to prepare for organised crime networks targeting Covid-19 vaccines, both physically and online.
In December in an interview with the German magazine WirtschaftsWoche, Stock said there would be a sharp rise in warehouse break-ins and attacks on vaccine shipments due to the vaccine roll-out.
Interpol said it had received reports of fake vaccine distribution and scam attempts targeting nursing homes and warned that no approved vaccines are available for sale online.
"Any vaccine being advertised on websites or the dark web will not be legitimate, will not have been tested and may be dangerous," Interpol said.
