The U.S. COVID-19 vaccination program has gone from zero to 50% in less than six months.

As of Tuesday afternoon, the Biden administration said, half of the country's adults are now fully vaccinated against the coronavirus.

This is a major milestone in our country's vaccination efforts, Andy Slavitt, a White House senior adviser on the COVID-19 response, said during a midday briefing. The number was 1% when we entered office Jan. 20.

source: npr.org