GRAPHICS
The Pfizer-BioNTech COVID-19 vaccine was the first to be approved by the U.S. Food and Drug Administration, with first doses shipped out around the country in December 2020.
Another vaccine, this one made by Moderna, has received emergency authorization as well, and the first shipments arrived during the last week of December. The next major hurdle for both companies is transporting the vaccine safely.
More than half of vaccines may be wasted globally every year because of temperature control, logistics and shipment-related issues, according to the World Health Organization.
Vaccines need to stay in a certain temperature range, usually refrigerated, to remain effective.
Multiple steps are needed to deliver vials of vaccine to local hospitals and pharmacies for injection into a person’s arm.
The low-temperature "cold chain" that runs from vaccine production to administration represents one of the biggest challenges of the vaccine distribution effort.
Another hurdle for the cold chain is that the vaccines from Pfizer and Moderna both require two doses, spaced several weeks apart. This means the right number of doses must be available at the right time for injection of the second dose.
Pfizer ships boxes with vaccine via companies such as UPS and FedEx to locations around the country. The company also plans to use a distribution center in Pleasant Prairie, Wisconsin.
Once vials with vaccine are transferred to a refrigerator, they must be used within five days. A single vial should provide five doses of vaccine after dilution. However, pharmacists have reported that vials contain extra doses.
As for Moderna, the vials with vaccine will travel from Massachusetts, New Hampshire, and Indiana to McKesson Corporation’s distribution center in Irving, Texas, the hub of the federal government’s Operation Warp Speed vaccination initiative.
The Moderna vaccine can tolerate much higher temperatures during shipping than the one from Pfizer, and has a longer shelf life once it reaches the administration location.