As we discussed in a previous blog post, cold storage is playing an ever-increasing and important role in the vaccine rollout for COVID-19.
According to a recent report in the biotech publication Lab Manager, the vaccine supply chain is evolving as logistics solutions are being developed to overcome challenges related to extreme cold storage temperature requirements.
One of the COVID-19 frontrunners, Pfizer’s BNT162b2, must be stored at an ultralow -94°F (-70°C). Pfizer doses are being shipped by road and air from the company’s production site in Kalamazoo, Mich., or distribution center in Pleasant Prairie, Wisc., to point of use locations, according to a Pfizer fact sheet.
United Parcel Service hubs and intermediate cold storage facilities, similar to Washington Cold Storage, are also part of the supply chain. Pfizer says it is using dry ice to maintain low temperatures in transit and GPS-enabled thermal sensors to enable real-time tracking of the location and temperature of each individual shipment. Shipping containers must be opened no more than twice per day and for no longer than one minute each time.
Once the Pfizer doses reach vaccine centers, they may be stored at a more easily achieved 35-46°F (2-8°C) for up to five days.
Moderna’s mRNA-1273, the second major vaccine to be approved for distribution, needs a less extreme -4°F (-20°C) to avoid degradation, however it still requires administration within a 12-hour room temperature window and cannot be re-frozen once it comes to room temperature.
Why so cold?
Both vaccines are made from messenger RNA, or mRNA, which enables a patient to produce a coronavirus protein that kicks off an immune response — but which is easily susceptible to breaking down, according to an NPR report. Freezing at extreme low temperatures prevents enzymes from breaking down the mRNA that makes the vaccine effective.
Biopharmaceutical companies are also using ultralow temperature freezers to ship vaccines long distances. These freezers employ a cascade refrigeration system that can use up to two compressors to achieve temperatures of 112°F (-80°C).
Photo credit: Navy Medicine