Why it's easier to find Pfizer's updated COVID boosters than Moderna's

Vaccinators around the country are reporting weeks-long delays in shipments of Moderna's updated COVID-19 vaccine boosters. The delays come after the Food and Drug Administration flagged concerns at a facility contracted to fill the Moderna's new shots into vials. 

The wait stems from an Indiana plant operated by Catalent, which is one of two firms that has been bottling Moderna's vaccine in the U.S. 

Following an inspection, the FDA this month faulted the Moderna contractor for falling short in its quality control procedures, and failing to "thoroughly investigate" batches discovered to be contaminated. Since September 2020, the company had received 179 complaints over impurities in its vials.