The U.S. has now distributed more than 9 million doses of COVID-19 vaccines since Dec. 14 — a total that increased by nearly 5 million doses in the past seven days.
According to the Centers for Disease Control and Prevention's COVID-19 vaccine tracker, the U.S. had distributed 8.9 million doses of Pfizer's and Moderna's COVID-19 vaccines as of Monday afternoon.
That number has more doubled in the past week, as the CDC reported that 4 million doses had been distributed as of Jan. 4.
The vaccination output has likely increased in recent weeks as states expand the availability of the drugs to more people. Most states initially reserved the vaccines for healthcare workers and people in nursing homes; some states have now opened vaccinations to all older people.
Despite the increased output, the U.S. remains well behind the goals set by Operation Warp Speed — the joint effort from the Department of Defense and the Department of Health and Human Services, which is tasked with distributing the vaccines. In December, Operation Warp Speed leaders said they hoped to distribute 20 million vaccine doses by the end of 2020.
President-elect Joe Biden, who received his second dose of Pfizer's COVID-19 vaccine on Monday, has set a goal to distribute 100 million doses of COVID-19 vaccines in his first 100 days in office. His top health officials are considering advising that some Americans only take one dose of Moderna's vaccine instead of the recommended two in the hopes of increasing the distribution totals.
While studies have shown a single shot of Moderna's vaccine can promote resistance to COVID-19, scientists warn that limiting Americans to a single dose could come with risks.