Hospitals and health ministries in 40 countries have been targeted by scammers offering vaccines against Covid-19 that turn out to be non-existent.
Interpol issued an alert to its 194 members which said the fraudsters posed as vaccine manufacturers and used fake social media accounts and websites.
In at least 60 cases, buyers received spurious offers to purchase vaccines that were approved in their country.
It is the latest in a series of Covid-related swindles which have led to companies being duped into buying fake masks and bogus vaccine passports traded online.
Real vaccines are distributed by healthcare officials and no legitimate shots are available for sale online.
Interpol said fraudsters targeted health workers and officials through their personal and professional email accounts and sometimes by phone.
They tried to impersonate drug makers or government agencies and offered vaccines for sale which would never arrive.