The nation is already grappling with a shortage of the specialized glass used to make the vials that will store any vaccine. Producing and distributing hundreds of millions of vaccine doses will also require huge quantities of stoppers — which are made by just a handful of companies — as well as needles and refrigeration units. Low stocks of any one of these components could slow future vaccination efforts, much as shortfalls of key chemicals delayed widespread coronavirus testing…

“Probably the biggest challenge will be scaling up the actual vaccine. It’s one thing to have clinical trial samples and materials in lab quantities,” said George Zorich, a pharmacy expert and CEO of ZEDPharma. “It’s another challenge actually scaling that up effectively.”

Potentially making it even harder is that the U.S. is striking out on its own. The administration has snubbed an international collaboration spearheaded by the World Health Organization, while the president readies for a November election that could be a referendum on his coronavirus response.