The U.S. Food and Drug Administration has confirmed that none of the flu vaccine quarantined by British officials is safe for use.

An FDA spokeswoman says agency personnel have inspected and rejected all 46 million doses at a Liverpool, England, factory of the Chiron Corporation, which manufactured the vaccine. She said the company violated good manufacturing processes, and that all the vaccines are suspected to be contaminated.

Last week, British officials shut down the plant, causing a huge shortfall of flu vaccine in the United States.

The vaccine shortfall - roughly half the U.S. supply - means there will not be enough to protect vulnerable children and elderly people.

Flu and its complications, such as pneumonia, kill 36,000 Americans and cause 200,000 hospitalizations per year.