Science

Why the COVID-19 Vaccines Must Be Kept So Cold

Nov 20, 2020

Image: Cheddar

After eight daunting months of battling COVID-19, there may be some light at the end of the tunnel as two potential vaccine candidates recently announced promising test results.

Vaccines from Pfizer and Moderna are similar in that they both use emerging technology called messenger ribonucleic acid (mRNA) to reach nearly 95 percent efficacy. Typically, scientists create vaccines by using live or inactivated virus cells, which puts the actual disease into a person’s body. However, with mRNA technology, Pfizer and Moderna were able to avoid that. MRNA carries coded instructions that tell cells what defenses are necessary by appearing as a threat.

Of Course, There's a Catch

The use of the molecule is groundbreaking for a number of reasons. One is the speed at which the vaccines were developed. The other is that the use of mRNA means the vaccines contain no infectious COVID-19 properties that could get patients sick.

However, there is a drawback to the vaccines: they have to be stored in brutally cold temperatures.

Under normal circumstances, vaccines can survive when stored at around 40 degrees Fahrenheit, but for Moderna, the vials must be stored at -4 degrees.

For Pfizer's vaccine, the threshold for keeping an effective dose is even steeper at a staggering -94 degrees. The icy temperatures are necessary to keep the mRNA molecule intact, otherwise it “begins to fall apart and twist around in ways so that it doesn’t become effective,” a representative for the pharmaceutical giant told Cheddar.

Vaccine Storage & Distribution Roadblock

With the need for cold storage comes the obstacle of how to pull off widespread distribution. Most hospitals in the U.S. do not house facilities that meet the requirements to store either the Moderna or Pfizer vaccines for extended periods. Both vaccines are able to survive in typical storing temperatures of 35 to 46 degrees, but their shelf lives are limited that way.

For Pfizer, the vaccine would no longer be effective after five days in normal storage temperatures. Moderna, meanwhile, shows more promise when it comes to effective distribution as it’s vaccines appear to remain effective for a month while stored 35 degrees.

Pfizer has come up with a plan to ship its vaccine in boxes filled with dry ice. The vials will remain protected for up to 15 days -- but the container can only be opened up to two times per day.

This could be a logistical nightmare for parts of the world that don't have sufficient equipment - or enough dry ice - to keep the vaccines. Even in rural America, many hospitals don't have freezers that can keep doses cold enough, particularly for the Pfizer vaccine.

Getting Vaccinated

So what does this mean for you? Once the FDA approves emergency use authorization of either one or both of the vaccines, it looks like they will likely be distributed first among populations that need it the most: frontline healthcare workers, the elderly, and those suffering from underlying health conditions.

Like several existing vaccinations for other conditions, both Pfizer and Moderna require two rounds of treatment in order for the body to build up complete immunity. For those receiving the Pfizer vaccine, patients will need to return for a second dose after three weeks and for those getting the Moderna vaccine, they'll have to go back for round two after four weeks.

Video produced by Ali Larkin. Article written by Lawrence Banton.