• Massive winter storms across the Midwest and Texas have delayed the delivery of 6 million Covid-19 vaccine doses across the U.S., top U.S. health officials said Friday.
• The backlog represents three days' worth of delayed shipments, said Andy Slavitt, White House senior advisor for Covid response.
• The Biden administration believes it will be able to handle the backlog alongside new production coming online next week.

Massive winter storms across the Midwest and Texas have delayed the delivery of 6 million Covid-19 vaccine doses affecting every state in the U.S., the nation's top health officials said Friday.

The backlog represents three days' worth of delayed shipments, Andy Slavitt, White House senior advisor for Covid response, said during a press briefing.

"Many states have been able to cover some of this delay with existing inventory," Slavitt said.

The delayed shipments stem from three main choke points in the vaccines' distribution chain caused by the weather, he said. Delivery hubs at UPS, FedEx and McKesson, which have been charged with delivering the doses to the states, have reported staffing shortages.

Slavitt said their workers "have been snowed in and unable to get to work to package" the vaccines, administration kits and other supplies.

Road closures have also held up the delivery of the vaccines between manufacturing sites and shipping hubs. On top of that, more than 2,000 vaccine distribution sites are unable to receive doses because they're in locations hampered by power outages, he said.

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Because of strict cold-chain requirements for storing the doses at ultra-cold temperatures, it's better to hold back the shipments than to send them to places where the shots might expire if they can't be administered within three days. He said the vaccines are "sitting safe and sound in our factories and hubs ready to be shipped."

"As weather conditions improve, we are already looking to clear this backlog," Slavitt said, adding that 1.4 million doses are being shipped on Friday. He said the administration anticipates "all the backlog doses will be delivered in the next week."

"We expect we will be able to manage this backlog and the new production coming online next week," Slavitt said.

Prior to Friday's briefing, state officials across the U.S. starting sounding alarms that their vaccine shipments were delayed this week. The massive winter storm has shuttered distribution hubs and left millions of people without power across states such as Texas, Louisiana and Mississippi.

White House Chief Medical Advisor Dr. Anthony Fauci warned on Thursday that the power outages and winter storm across Texas this week pose a "significant" problem for Covid-19 vaccine distribution. The Biden administration is asking immunization sites to extend their hours and offer additional appointments over the coming days and weeks to help catch up, Slavitt said Friday.

"If we all work together, from the factory all the way to the vaccinators, we will make up for it in the coming week," he said.

Slavitt also announced Friday that the administration is working with Florida and Pennsylvania to open five additional vaccination centers.

Four of the five vaccination centers will be in the Florida cities of Jacksonville, Miami, Orlando and Tampa, he said, adding the four sites will have the capacity to vaccinate a total of up to 12,000 people per day. The fifth center will be in Philadelphia, he said, and will be able to vaccinate 6,000 people per day.