The U.S. Food and Drug Administration (FDA) announced Thursday it is allowing the mRNA vaccine by Pfizer-BioNTech to be stored at the standard freezer temperature for a period of up to two weeks.
Pharmaceutical freezers and refrigerators can facilitate the standard freezer temperatures of -25 to -15 degrees Celsius (-13 to 5 degrees Fahrenheit). The approval comes several days after the companies said they submitted new data to the FDA that shows vials of undiluted vaccine remain stable when stored at these temperatures for up to two weeks.
This storage option is an alternative to storing the undiluted vials in ultra-low temperature freezers at -80 to -60 degrees Celsius (-112 to ‑76 degrees Fahrenheit), the FDA announced. The change will also be updated in an FDA fact sheet (pdf) for frontline healthcare workers administering the vaccine.
The vaccine vials can be stored in ultra-low temperature freezers for up to six months. Labels for the vaccine stipulated that vials must be shipped in specially-designed cool boxes filled with dry ice that have to be refilled every five days, and can remain in temporary storage like this for up to 30 days.
Once out of the freezer storage, the thawed undiluted vaccine vials can be kept at a standard refrigerator temperature of between 2 and 8 degrees Celsius (36 to 46 degrees Fahrenheit) to remain effective for up to five days. The vaccine is then diluted, and can be held at refrigerator temperature or room temperature for use within 6 hours, according to the FDA. As per protocol, the vaccine is administered at room temperature.
The now-approved option to store the vaccine vials at standard freezer temperatures will provide more flexibility for transport of vaccines across the country before it is thawed and administered to patients.
“This alternative temperature for transportation and storage of the undiluted vials is significant and allows the vials to be transported and stored under more flexible conditions,” Peter Marks, director of the FDA’s Center for Biologics Evaluation and Research, said in a statement. “The alternative temperature for transportation and storage will help ease the burden of procuring ultra-low cold storage equipment for vaccination sites and should help to get vaccine to more sites.”
Pfizer’s vaccine was the first time the FDA has approved for Emergency Use Authorization a product that uses messenger RNA (mRNA) technology.
“The vaccine contains a small piece of the SARS-CoV-2 virus’s mRNA that instructs cells in the body to make the virus’s distinctive ‘spike’ protein,” an FDA announcement of the Pfizer vaccine reads. “When a person receives this vaccine, their body produces copies of the spike protein, which does not cause disease, but triggers the immune system to learn to react defensively, producing an immune response against SARS-CoV-2.”
Vaccine providers are required to report any serious adverse effects or vaccination administration errors to the Vaccine Adverse Event Reporting System (VAERS), hosted by the Department of Health and Human Services. Vaccine manufacturers are immune from liability for any adverse reactions unless there is “wilful misconduct” involved. The federal government has a Countermeasures Injury Compensation Program that can pay compensation to eligible persons who suffer serious injury from approved vaccines. However, burden of proof has proven a challenging process.
The Pfizer-BioNTech vaccine is administered in two separate doses, several weeks apart. The companies are carrying out a new trial to see whether a third dose of their vaccine would further protect people against COVID-19, the disease caused by the CCP (Chinese Communist Party) virus, and emerging virus variants.
Melanie Sun contributed to this report.