EU lawmaker Peter Liese, from the same party as German Chancellor Angela Merkel, said the report left him speechless, and he urged AstraZeneca to clarify the situation.
Uzbekistan last week received its first 660,000-dose batch of the AstraZeneca vaccine, provided for free under the COVAX initiative. "We are waiting to receive 1.5 million doses of the same vaccine," he said.
The Geneva-based body urged vigilance as case numbers rise in several regions, including Europe, driven partly by virus variants that transmit more easily.
The self-ruled democratic island has signed contracts to purchase 10 million AstraZeneca doses, as well as around 5 million doses each from Moderna and the international Covax scheme.
Antarctica was one of the last places on Earth to be affected by the virus, but on December 21, an outbreak was reported at a Chilean army base, with 36 people infected.
The supply issues added to the firm's troubles, with some countries including Denmark, Norway and Iceland suspending use of its shot over concerns over side effects such as blood clots.
COVAX is co-led by the WHO, the GAVI vaccines alliance, the Coalition for Epidemic Preparedness Innovations (CEPI) and the United Nations children's fund UNICEF.