Beyond 100M: Biden team aiming for bigger vaccine numbers

Now comes the far more ambitious and daunting mission of vaccinating all eligible adults against the coronavirus by the end of the summer.

Limited supply of the two approved vaccines has hampered the pace of vaccinations, and that was before extreme winter weather delayed the delivery of about 6 million doses this past week.

But the U.S. is on the verge of a supply breakthrough as manufacturing ramps up and with the expectation of a third vaccine becoming available in the coming weeks.