Pharmaceutical companies Moderna and Pfizer/BioNTech have spurred optimism that a novel type of vaccine made from messenger RNA, known as mRNA, can offer high levels of protection by preventing COVID-19 among people who are vaccinated.
How Does mRNA Vaccine Work?
Vaccines train the immune system to recognize the disease-causing part of a virus. Vaccines traditionally contain either weakened viruses or purified signature proteins of the virus.
But an mRNA vaccine is different, because rather than having the viral protein injected, a person receives genetic material – mRNA – that encodes the viral protein. When these genetic instructions are injected, the muscle cells translate them to make the viral protein directly in the body.
This gives the immune system a preview of what the real virus looks like without causing disease. This preview gives the immune system time to design powerful antibodies that can neutralize the real virus if the individual is ever infected.
Why Does mRNA Have To Be Kept At Super Cold Temperatures?
The most important challenge for development of a mRNA vaccine remains its inherent instability, because it is more likely to break apart above freezing temperatures.
What are the refrigeration requirements?
The Pfizer/BioNTech mRNA vaccine will need to be optimally stored at -94 degrees Fahrenheit and will degrade in around five days at normal refrigeration temperatures of slightly above freezing.
In contrast, Moderna claims its vaccine can be maintained at most home or medical freezer temperatures for up to six months for shipping and longer-term storage. Moderna also claims its vaccine can remain stable at standard refrigerated conditions, of 36 to 46 degrees Fahrenheit, for up to 30 days after thawing, within the six-month shelf life.