100 million Americans are now fully vaccinated against COVID-19, according to the CDC's tracker.

Why it matters: That's 38% of the country's adult population — and 55% of the adult population has had at least one shot. All told, the U.S. has administered nearly 240 million shots.

• That is an enormous success, in such a short time. But, of course, it only gets harder from here — both domestically and globally.

What's next: Moderna is planning to dramatically expand its manufacturing capacity, both to keep up with the extreme global demand and to start making booster shots to address COVID-19 variants.

• The company upped its minimum expected output for this year, saying it now expects to make at least 800 million doses, and that it'll be able to make as many as 3 billion doses in 2022.

Between the lines: The U.S. has a stranglehold on the Pfizer and Moderna vaccines doses right now, and Moderna said it's increasing its domestic manufacturing capacity by 50%.

• But it's also making big investments in overseas facilities, which will allow it to serve more of the world.
• For the first time, Pfizer is now exporting some of the doses it's making in the U.S., Reuters scoops.

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