Pfizer (mRNA Vaccine) 95% effective*
2 dose series (0.3mL each) given 21 days apart
Multidose vial containing up to 6 doses/vial
Dilute with 1.8 mL of 0.9% Sodium Chloride
43,448 trial participants
Authorized for use in individuals > 16 years
Published safety and final efficacy results from Phase 3 trial on December 10, 2020
Moderna (mRNA Vaccine)
94.5% effective*
2 dose series (0.5 mL each) given 28 days apart
Multidose vial containing 10 doses
No dilution required
30,420 trial participants
Authorized for use in individuals > 18 years
Announced primary efficacy results from Phase 3 trial on November 30, 2020
*vaccine efficacy is against COVID-19 in individuals without prior SARS-CoV-2 infection
What is mRNA and how do mRNA vaccines work?
• Messenger RNA, or mRNA, is the blueprint for making proteins. Within the nucleus of cells, DNA makes mRNA and then ships it into the surrounding cell cytoplasm. In the cytoplasm, mRNA is translated into proteins and enzymes. Soon after this, the mRNA breaks down.
• COVID-19 mRNA vaccines take advantage of the cellular process of making proteins by introducing mRNA that contains the blueprint for one of the coronavirus proteins, specifically the spike protein. This protein is responsible for attaching the coronavirus to our cells.
• COVID-19 mRNA vaccines are given in the upper arm muscle. Once the mRNA is inside the immune cells of the muscle tissue, the cells follow the instructions and make the spike protein piece.
• Next, the cell displays the protein piece on its surface. Our immune system recognizes that the protein doesn’t belong there and begins mounting an immune response and making antibodies.
• After developing antibodies, our immune system can protect against future infection.
• The benefit of the mRNA vaccine is those vaccinated gain the protection without risking the serious consequences of getting sick with COVID-19.
What other ingredients are included in the vaccines?
There has been complete transparency around ingredients. You can find the fact sheet for each vaccine posted on the FDA’s website with the exact list of ingredients. In addition to the mRNA, both vaccines include:
Lipids: Molecules or “bubbles of fat” that surround the mRNA to protect it, so it does not break down before it gets into our cells.
Salt: Similar to table salt, it keeps the pH of the vaccine close to that of the body, so the vaccine doesn’t damage the cells.
Sugar: Similar to sugar we eat, in the vaccine it helps keep the “bubbles of fat” from sticking to the vaccine vial