States ramp up for biggest vaccination effort in US history

This 2020 photo provided by Carlton County shows their drive-thru flu clinic in Carlton, Minn. The facility is a way to social distance in the coronavirus pandemic, but also served as a test run for the COVID-19 vaccines that county health officials still know little about. (Jared Hovi/Carlton County GIS via AP)

With a COVID-19 vaccine drawing closer, public health officials throughout the country are gearing up for the biggest vaccination effort in U.S. history — a monumental undertaking that must distribute hundreds of millions of doses, prioritize who’s first in line and ensure people who get the initial shot return for the necessary second one.