With a spotlight on COVID-19 vaccine distribution shortcomings, there's another bottleneck that could prevent inoculations from significantly speeding up in the near future: Pfizer's and Moderna's ability to scale up manufacturing and deliver doses to the U.S. government.
The companies promised to deliver 100 million doses apiece to the United States by the end of March. But they'll need to make huge leaps in a short time to meet that goal.
In the last few weeks, they've each been steadily delivering about 4.3 million doses a week, according to an NPR examination of vaccine allocation data. But to hit their targets of 100 million doses on time, they each need to deliver 7.5 million doses a week for the next nine weeks.
"I think it is going to be a real challenge for them to hit that contracted target. There's just no question about that," said consultant John Avellanet, who's advised pharmaceutical companies since the 1990s on manufacturing and compliance issues.
The companies would need everything to go right.
And a lot can go wrong. Equipment breaks and needs repair. Doses need to pass quality tests before they can be shipped. And the production process depends on companies maintaining a steady supply of chemical ingredients, glass vials and skilled labor.
"In some ways, it's almost a miracle that they've been able to produce what they've been able to produce," Avellanet said.
Pfizer and Moderna vaccines both rely on messenger RNA, or mRNA, to protect against the virus. Although mRNA vaccines have been studied for a decade, it's the first time they've been used on a massive scale.
"It's one thing to make 300 vials or let's say even for a clinical trial, 3,000 vials. It's a whole other game to make 4 million, 7 million," Avellanet said. "And all of a sudden, the demands are huge. And so you're going to end up with machinery that gets out of calibration, that breaks down ... and so forth and so on. And so that can slow the process dramatically."
What's more, RNA is fragile, said David Gortler, who until Wednesday afternoon was the senior adviser to the now-former Food and Drug Administration Commissioner Stephen Hahn.
"Going back to my Yale days when I was a lowly fellow inside of a molecular biology lab, I had to work with RNA myself," he told NPR. "And RNA is something which is very, very delicate and it can be inactivated, just like — we used to joke — just by looking at it the wrong way."
Gortler is a pharmacist and pharmacologist who specializes in drug quality and supply chain issues. He said he understands that Pfizer and Moderna are already working at "maximal capacity" with existing facilities. Building new facilities would require FDA inspections and "take a very long time."
When it comes to COVID-19 vaccines, he said quality is even more important than speed.
"I'd rather hear the companies have fallen short of their production goal, but managed to maintain their quality control because all of this really depends on the quality control," he said. "It's really the case for all drugs. So like I said before, but in this case, just because of the particular nature of this drug and the specific fragility of dealing with anything RNA-related, it's important to take a step back."
Asked about why vaccine delivery appeared to be behind and what's being done to speed it up, Operation Warp Speed spokesperson Michael Pratt in the Trump administration sent NPR the following statement just before the Biden administration took over:
Both companies continue to scale up production, and current forecasts indicate we are on track to allocate 200 million doses by the end of March across the vaccine portfolio. Operation Warp Speed continues to assess all available avenues to assist manufacturers to optimize and maximize their production processes as requested/required.
The new administration has said it plans to use the Defense Production Act to increase production. The Trump administration used the Defense Production Act 18 times as part of Operation Warp Speed, according to a Dec. 29 statement from the White House press secretary.
Moderna said it hasn't been releasing weekly or monthly production estimates, so it couldn't provide more details about how it will deliver significantly more doses to the United States in the coming weeks to meet its first-quarter goal.
"We continue to be on track with our expectations of delivering 100 million doses of vaccine by the end of Q1, and 200 million doses by the end of Q2," Moderna spokesperson Ray Jordan wrote in an email to NPR. "Production and releases are not linear and we have explained that we have been successfully scaling up our production yields over time."
On Dec. 15, Vice President Pence visited the Catalent contract manufacturing facility making finished vaccine doses for Moderna, where leadership told him they were completing 500,000 doses a day and hoped to double production to meet delivery goals. They described employees working "tirelessly" and volunteering to work Thanksgiving and Christmas.
Pfizer didn't respond to NPR's request for comment. But it slashed vaccine deliveries for some European Union countries this week, according to Reuters.
Gortler said he worked at Pfizer for several years, and if it's running behind, it's probably because of its attention to quality. "I'm sure that if they're rejecting things, that's actually what you want to hear," he said. "So in my mind, it's a good thing."
To hit their goals, Moderna and Pfizer each need to increase shipments to 7.5 million doses from 4.3 million per week in a hurry.
The task is difficult but not impossible.
John McShane, a managing partner at the health care product consulting firm Validant, said he's "guardedly optimistic" that the companies will be able to scale up manufacturing drastically and deliver 100 million doses each by March 31.
He said there are three main "levers" the companies can pull to increase production: add equipment, increase the yield per batch and find ways to shorten the time it takes to go from raw materials to finished, internally approved product.
"Those are three pretty big levers," McShane said. And outsourcing could help, too. "One CMO [contract manufacturing organization] with the right capacity could double your throughput overnight," he added.
What's more, he said, it's likely that the doses Moderna and Pfizer plan to deliver on March 31 are already somewhere in the production process.