More than 15 million doses of COVID-19 vaccines have been thrown away over the past six months.
Data obtained by NBC News from the U.S. Centers for Disease Control and Prevention (CDC) finds that the true level of vaccine waste in the country is higher than previously expected.
The 15 million doses have been discarded since March, when the vaccines first started to become widely available for all adult Americans.
Large pharmacy chains and state health departments were most responsible for the waste of vaccines.
The data is revealed after the nation's vaccine roll out faltered for months during late spring and early summer, until demand for the jabs began to rise again once a Delta variant-fueled Covid surge began.
More than 15 million COVID-19 vaccine doses have been discarded since March, an NBC News report finds. Walgreens is responsible for the most vaccine waster, throwing out 2.6 million doses
CVS is among the biggest vaccine wasters as well, throwing away 2.3 million COVID-19 vaccine doses.
NBC aggregated vaccine waste data from vaccine providers across the country that it obtained through a public records request.
Walgreens, one of the nationwide pharmacy chains that partnered with the federal government to distribute vaccines, is responsible for the most waste at 2.6 million doses.
Around 2.3 million doses were reported as wasted by CVS, 1.6 million by Walmart and 1.1 million by Rite Aid.
Each of the chains have played a crucial role in distributing the vaccine nationwide so far.
NBC estimates that they totals reported are likely undercounts compared to the total doses wasted so far, though.
There are multiple reasons for vaccine doses to be discarded.
Sometimes, a vial will be opened to serve the next person who comes in for a vaccine.
There are multiple reasons for vaccines to be discarded. Some are unused doses as part of an open vial, some vials are damaged. Some also expired due to a lack of demand for the shots.
