Watch live: U.S. officials speak on Operation Warp Speed after Pfizer releases positive vaccine data

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The departments of Health and Human Services and Defense are holding a briefing Wednesday on the Trump administration's coronavirus vaccine program Operation Warp Speed after Pfizer released positive data on its Covid-19 vaccine.

Earlier in the day, Pfizer announced that a final data analysis found its coronavirus vaccine with BioNTech was 95% effective in preventing Covid-19, was safe and appeared to fend off severe disease. The company said it plans to submit an application for emergency use with the Food and Drug Administration "within days."

Pfizer announced on July 22 that the U.S. agreed to buy 100 million doses of its vaccine for up to $1.95 billion. The agreement, which is part of Operation Warp Speed, allows the U.S. to acquire an additional 500 million vaccine doses.

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