CHAPTER 6

• Jurisdiction: United States

CHAPTER 6 HOW ARE THE FOUR MAJOR COVID VACCINES DIFFERENT?

Among the Vaccine Candidates

• mRNA Vaccines

• ModernaTX, Inc.,¹ intramuscular injection of vaccine, two doses, twenty-eight days apart
• Pfizer BioNTech,² intramuscular injection of vaccine, two doses, twenty-one days apart

• Adenovirus Vaccines

• AstraZeneca³ and Johnson & Johnson⁴ received FDA emergency use authorization in early 2021⁵

Preservation

Deep cold is needed to preserve the vaccine doses.

• Pfizer Vaccine BNT162b2 needs to be stored at -70°C

• Can be stored at -28°C for five days
• Can be stored at room temperature for two hours, or six hours after dilution

• Moderna Vaccine mRNA-1273 needs to be stored at -20°C

• Can be stored at -28°C for thirty days
• Can be stored at room temperature for twelve hours

What Happens if the Vaccine Is Not Kept Cold?⁶

The potency of the vaccine requires an intact mRNA molecule, in order for its design to function. A minor degradation anywhere along the mRNA strand could result in slowed or halted performance, leading to incomplete expression of the target antigen.

In contrast to therapeutic proteins and protein antigens, these biological agents use RNA so they are often able to withstand multiple chemical degradation reactions.

Differences: What is the mechanism that messenger RNA vaccines use for specifically defending against COVID-19?

Moderna and Pfizer each identified and used the same "spike protein" in their vaccines. There is no difference in how the vaccines work. The only differences are in their dosage, storage, and manufacturing. The mRNA COVID-19 vaccines will use spike protein as its key target.

Why Will Vaccination Promote Early Resistance?

With COVID, there is an early viral phase, followed by an inflammatory phase. A person who has protection with a vaccine will not have much of that early viral phase, so they will not develop an inflammatory issue.⁷

How Will the Vaccines Reach Their Goal?

A leading virologist explained: "A goal of the messenger RNA vaccines is to have the neutralizing antibody titers stay high for periods of time, with annual boosters. The goal in designing the vaccine is to have it show the spike protein from SARS-CoV-2 so that your immune system is ready to respond, should you encounter the virus that causes COVID-19. There are different delivery ways, either serving up the mRNAs and your body's got to make the protein, or giving a viral vector from a known virus and the body of the vaccinated person will make the protein later."⁸

Why Are Two Doses Needed?

For some vaccines (primarily inactivated-viral vaccines), the first dose does not provide as much immunity as possible. More than one dose is needed to build more complete immunity. After a while, immunity begins to wear off. At that point, a "booster" dose is needed to bring immunity levels back up. This booster dose can be given days, months, weeks, or years apart. Studies have shown that more than one dose is needed for everyone to develop the best immune response, since some people may not develop enough antibodies to fight off infection. The second dose helps make sure that almost everyone is protected. The Janssen/Johnson & Johnson vaccine, however, requires only one dose.⁹

How Are Doses Delivered?

• The Pfizer-BioNTech COVID-19 Vaccine, BNT162b2 (30 µg), is administered intramuscularly (IM) as a series of two 30 µg doses (0.3 mL each), twenty-one days apart.
• The Moderna COVID-19 Vaccine is a two-dose series of 100-µg intramuscular injections administered one month apart.
• The Janssen/Johnson & Johnson vaccine is a one-shot intramuscular vaccine.

Delivery caution is very important. The temperature of the vaccine vial must be maintained throughout the shipping process and then in a storage facility prior to distribution to end-user sites for injection.

What Is Known About Differences Between Moderna and Pfizer Vaccines?

Details of the clinical trials have been published for each vaccine:

Pfizer

This vaccine received its FDA Emergency Use Authorization on Dec. 11...