On Friday the FDA granted an emergency use authorization for Pfizer and BioNTech's coronavirus vaccine.
The vaccine left Pfizer's Michigan facility on Sunday and shipped out across the country.
Sites are expected to get vaccine doses starting today, says Business Insider.
Pfizer's vaccine authorization means 2.9 million high-risk people will get the shot within days.
This is the first step in a 9-month path to normalcy.
The two-dose regimen from Pfizer and BioNTech is free to anyone who wants it in the US.