His office Thursday accused drug maker Aventis Pasteur of withholding key information from the U.S. Food and Drug Administration.
Blagojevich spokeswoman Abby Ottenhoff says it's a mystery why the French company isn't cooperating.
Aventis spokesman Len Lavenda says the company's working with the FDA, but he declined to go into specifics.
The governor has a tentative deal to buy about 262,000 doses of the vaccine that was manufactured for use in Canada and Europe. The FDA must determine whether the vaccine supply can be used safely in the United States.