Americans will start receiving the Pfizer-BioNTech Covid-19 vaccine on Monday, the official in charge of the distribution operation said Saturday. 

General Gus Perna told reporters the first doses will be shipped Sunday and that starting Monday morning, "We are operationally 100% confident that we will get the vaccines to the American people."

"Expect 145 sites across all the states to receive vaccine on Monday, another 425 sites on Tuesday. And the final 66 sites on Wednesday, which will complete the initial delivery of the Pfizer-BioNTech vaccine," he said.

The first push will vaccinate about three million people. 

Federal health authorities have recommended that health care workers and nursing home residents be at the front of the line, but the decisions will be left to states. 

The US became the sixth country to green light the Pfizer vaccine on Friday night.

It has been shown to be 95 percent effective in preventing Covid-19 infection compared to a placebo.

But the FDA has advised people who have severe allergies to ingredients in the drug to avoid getting immunized for the time being.