EXPLAINER: How have storms affected COVID-19 vaccinations?

NEW YORK (AP) — Efforts to vaccinate Americans against COVID-19 have been stymied by a series of winter storms and outages that have hobbled transportation hubs and highways in parts of the country not used to extreme cold weather.

That has created challenges for carriers such as UPS and FedEx, which have been on the front lines packaging and shipping the Moderna and Pfizer vaccines around the country. Both UPS's hub in Louisville, Kentucky, and FedEx's key hub in Memphis, Tennessee, have been affected. Meanwhile, several states have complained about vaccination delays and have had to cancel appointments.

The fact that 6 million doses have languished in airport hubs for several days during a once-in-a-century pandemic has raised questions about how the U.S. government and the nation’s largest shipping companies haven't been able — so far at least — to break the logjam.

WHAT'S THE PROBLEM?

White House officials say the snowstorms and power outages created a variety of challenges that slowed vaccination efforts in different ways. First, shippers like FedEx, UPS, and pharmaceutical distributor McKesson had to deal with workers who were snowed-in and couldn't package, ship the vaccine kits and do other jobs. Then, road closures in many states kept trucks from delivering the vaccines. Finally, more than 2,000 vaccination sites were in areas with power outages.

Still, the government is moving ahead with plans to open five new mass vaccination centers, one in Philadelphia, and four others in the Florida cities of Miami, Orlando, Tampa and Jacksonville.

HOW ARE CARRIERS TRYING TO FIX THE ISSUE?

FedEx says it's relying on other hubs around the country to fix the problem. That includes its shipping hub in Indianapolis — the company’s second largest after Memphis...