CHAPTER 8

• Jurisdiction: United States

CHAPTER 8 WHAT ARE THE BARRIERS TO SUCCESSFUL DELIVERY OF THE COVID VACCINE?

Although data concerning the efficacy and safety of the Pfizer and Moderna mRNA vaccines have been released, the limits of long-term stability are yet to be determined. Limits on stability assessment will be necessary for the Pfizer and Moderna vaccines as time proceeds, evaluating stability and quality control measures.¹ Stability assurance in COVID-19 mRNA vaccines requires special freezers for storage. The adenovirus vaccines, such as that from Johnson & Johnson, are not as delicate in their handling stages.

Vaccine cold chain logistics have been widely discussed in the 2020-2021 press coverage of the first two FDA Emergency Use Authorizations for mRNA vaccines. These vaccines require refrigeration systems and temperature regulation systems, especially during transportation. Most vaccines are stored at 2° to 8°C, standard refrigerator temperatures, yet for the mRNA vaccines against COVID, which require much lower temperatures, the rigid cold chain supply limits broader use of vaccines, specifically in underdeveloped countries, where cold conditions are often impossible to maintain in the final stages of end-user site distribution in remote regions.² This is a dynamic field of evolving scientific and processing changes.³

The vaccine-controlled temperature chain standards of the World Health Organization (WHO) require rigorous stability testing, and denotation within the licensure that allows certain vaccines to be stored at temperatures outside the recommended range for a specified amount of time. WHO is especially concerned about delivering vaccines to remote regions while maintaining potency and...