The Battle of the Vaccines: Pfizer/BioNTech vs. Moderna

Tampa, FL. On December 14th 2020, Tampa Bay healthcare workers received the first doses of the COVID-19 vaccine. In a pivotal moment in history, a life threatening disease was met with human ingenuity and determination, resulting in a highly effective vaccination. . . in fact multiple. Though we can’t choose which type of vaccine to receive, the availability of multiple options undoubtedly raises questions. How do the two vaccines really stack up?


Both vaccines show similar effectiveness. Developed by the pharmaceutical company Pfizer and German firm BioNTech, the Pfizer/BioNTech vaccine has a 95% efficacy at preventing the COVID virus, 7 days after the second dose. On the other hand, the Moderna vaccine, developed by a Massachusetts biotechnology company, proved to be 94.1% effective, 14 days after the second dosage.

RNA Technology

The similar levels of effectiveness for both vaccines can be attributed to their usage of messenger RNA (mRNA) technology, which contains code for cells to generate a unique identifier on the COVID-19 virus body called “spike proteins.” Basically, the vaccine tells our cells to produce a unique part of the COVID-19. Our immune system, then, develops an immune response using specific immune cells called T and B lymphocytes and voila! Patients receiving the vaccine develop the immunity to COVID-19.

Booster Dose

Both vaccines require a “priming dose” and “booster shot,” however the interval for the Pfizer doses is only 21 days with 30 micrograms per dose, while the interval between the Moderna doses is 28 days with 100 micrograms per dose — almost three times the Pfizer vaccine’s amount; ultimately a minor difference.


Demanding more maintenance, the Pfizer vaccine must be stored at -94ºF and shipped in containers insulated with dry ice. Its minimum purchase order is 975 doses, which may be too much for regions lacking large hospitals. The Moderna vaccine has a more manageable purchase order at 100 doses and only needs to be stored at -40ºF.

New Hope

Although the availability of multiple vaccines may generate confusion, the options are both highly effective and represent an engineering feat in vaccine development.  As the human population recoils from the devastation of COVID-19, we look to a new year with hopes of returning to normal.  In the meantime, the CDC recommends continuing social distancing and  mask usage as before. The possibility of leaving the mask at home may not be far ahead.