3 reasons COVID-19 vaccines remain in short supply

Though the U.S. has invested billions of dollars in COVID-19 vaccine manufacturing and invoked the Defense Production Act to boost supplies needed to make the vaccines, there are still not enough doses to meet demand, Kaiser Health News reported Feb. 23. 

Experts told Kaiser Health News that three main bottlenecks are contributing to the lack of supply: 

1. The production of lipids. Both Moderna and Pfizer's vaccines contain billions of lipids, and lipids are only made in a handful of U.S. factories, Kaiser Health News reported.
   
   "No one has ever thought of a scenario where we would use lipid nanoparticle formulation for [billions of] doses," Prashant Yadav, PhD, a senior fellow at the Center for Global Development at Harvard University, told Kaiser Health News. "We have not invented a process for doing lipid nanoparticles at scale."
   
   Before COVID-19, the companies making the lipids made only small amounts, mainly for use for such things as clinical trials, according to Kaiser Health News. It takes time to get FDA authorization for a facility to make large quantities of lipids, so Moderna and Pfizer have been forming agreements with existing manufacturers to convert to lipid production, Pieter Cullis, PhD, a University of British Columbia professor, told Kaiser Health News.
   
   
2. The availability of glass vials. Though the Defense Production Act has been invoked to require some glass makers, such as Corning and SiO2 Materials Science, to prioritize making vials to store vaccines, it takes time to get the needed equipment installed to boost production, Prashant Yadav, a senior fellow at the Center for Global Development at Harvard University, told Kaiser Health News.
   
   
3. Filling the vials. Vaccine-filling lines that get the finished vaccines into vials or syringes must be extremely efficient and sterile, Kaiser Health News reported. Few companies in the world are up to the task, Mike Watson, former president of Valera, a subsidiary of Moderna, told Kaiser Health News.
   
   Moderna has hired a company named Catalent to fill and finish its vaccine doses at a facility in Bloomington, Ind., as well as at least two other companies to do the same for its vaccines abroad, according to Kaiser Health News.
   
   Sanofi agreed to let Pfizer use its fill/finish vaccine line in Germany for its vaccine, but that line isn't expected to be up and running until July, Kaiser Health News reported. 

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