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What Do We Know About the COVID-19 Vaccines?

By Rosanna Sutherby, PharmD

December 03, 2020

Ask A Pharmacist

Nearly a year ago, a new coronavirus we now know as SARS-CoV-2 changed the entire world with the global spread of a disease that scientists named COVID-19. Since then, researchers have been working tirelessly to find medications to treat the disease and a vaccine to put an end to the devastation this pandemic has caused. This November, two vaccines emerged as frontrunners, with over 90% efficacy rates.

Which COVID-19 Vaccines Are in Late-Stage Trials?

Numerous COVID-19 vaccines are in various stages of clinical trials across the world. As of November 24, 2020, five vaccines are in phase 3 clinical trials in the United States. Phase 3 is the last step in testing vaccines in humans. The following manufacturers have vaccines in phase 3 trials:

AstraZeneca
Janssen
Moderna
Novavax
Pfizer/BioNTech

The Pfizer/BioNTech Vaccine

Pfizer partnered with German company BioNTech to develop a vaccine against COVID-19. On November 9, 2020, Pfizer and BioNTech announced that their vaccine is more than 90% effective. Later they concluded that the vaccine is 95% effective and has no serious safety issues. The most frequently reported side effects in clinical trials were fatigue and headache.

Immunization with the Pfizer and BioNTech vaccine requires two shots given three weeks apart. Pfizer plans to produce 50 million doses worldwide in 2020 and up to 1.3 billion doses throughout 2021.

The Moderna Vaccine

A week after Pfizer’s historic announcement, Moderna followed with the results for its vaccine. On November 16, 2020, Moderna reported that its vaccine is 94.5% effective with no serious safety issues. The most frequently seen side effects in clinical trials include:

Pain and redness at the injection site
Fatigue
Muscle or joint pain
Headache

The Moderna vaccine is also a two-shot series, but it is given four weeks apart. Moderna plans to produce about 20 million doses of vaccine by the end of 2020 and 500 million to 1 billion doses worldwide throughout 2021.

How Do Vaccines Work?

Vaccines are substances that help your body develop antibodies against specific diseases without getting an infection. Antibodies help fight the infection and develop memory cells to attack the infection if it enters your body in the future.

Currently, there are three main types of COVID-19 vaccines in phase 3 clinical trials:

Messenger RNA (mRNA) vaccines
Protein subunit vaccines
Vector vaccines

Both the Pfizer and the Moderna vaccines are mRNA vaccines.

What Are mRNA Vaccines?

Many vaccines use weakened or inactivated germs to stimulate your body to produce an immune response. COVID-19 mRNA vaccines are a new type of immunization that does not use the COVID-19 virus to trigger an immune response. Instead, they use mRNA, a molecule that carries information from DNA to tell cells to make a specific protein.

COVID-19 vaccine mRNA instructs your cells to make the spike protein found on the coronavirus. Because your body is not making the actual coronavirus, you do not get sick with COVID-19 after being vaccinated. When a COVID-19 vaccine is injected into your muscle, the mRNA tells your muscle cells to make the harmless spike protein. After this work is finished, the cells destroy the instructions and eliminate them.

The muscle cells then place the spike protein on the cell surface. When your body sees the spike protein, it recognizes it as an antigen (a substance that is foreign to your body and that induces an immune response). Your immune system then starts to make antibodies to fight the antigen and memory cells that can fight the virus if your body encounters it in the future.

Where Do the COVID-19 Vaccines Stand in the FDA Approval Process?

As of this article’s writing, no vaccine has been approved by the FDA to prevent COVID-19. Pfizer has met the safety data milestones required by the FDA and applied for Emergency Use Authorization (EUA) on November 20, 2020. Ten days later, Moderna met the same requirements and applied for EUA on November 30, 2020.

What Is an Emergency Use Authorization?

An EUA is a way in which the FDA allows the use of medications or vaccines during public health emergencies like the current pandemic. For the FDA to approve an EUA for a COVID-19 vaccine, the vaccine's potential benefits must outweigh the potential risks to the population. The manufacturer must provide adequate safety follow-up of at least half of the people who received the vaccine for at least two months after having completed the vaccinations.

The FDA reviews the safety and efficacy data and decides if it is safe to use the vaccine. On December 10, 2020, FDA advisory committees will hold a public meeting to discuss the EUA application submitted by Pfizer and BioNTech.

Who Will Get the COVID-19 Vaccine First?

The CDC’s Advisory Committee on Immunization Practices will make recommendations on who should be vaccinated first once the FDA approves emergency use applications for the COVID-19 vaccines. If there is a limited supply of vaccine, the following groups will likely be considered for early vaccination:

Healthcare workers
Essential and critical workers
People who are at high risk for severe COVID-19 illness
People 65 years and older

What Happens Next?

The development of COVID-19 vaccines is ongoing. Vaccine candidates are still in clinical trials worldwide, including several in phase 3 trials. Even after phase 3 trials are complete, manufacturers will continue to monitor those who receive vaccines for side effects and safety issues. We will continue to watch for decisions from the FDA. Both Pfizer and Moderna are positioned to begin vaccine distribution immediately upon EUA approval.

Rosanna Sutherby is a freelance medical writer who has been a practicing pharmacist in her community for close to 20 years. She obtained her Doctor of Pharmacy from Nova Southeastern University in Ft. Lauderdale, FL. She is a certified immunizer and utilizes her clinical training in the pharmacy, where she helps patients manage disease states such as asthma, diabetes, heart disease, hypertension, and many others. Dr. Sutherby reviews and recommends drug regimens based on patients' concurrent conditions and potential drug interactions.

References:

https://www.wellrx.com/news/understanding-the-vaccine-development-process/

https://www.cdc.gov/coronavirus/2019-ncov/vaccines/different-vaccines.html

https://www.npr.org/sections/health-shots/2020/11/09/933006651/pfizer-says-experimental-covid-19-vaccine-is-more-than-90-effective

https://www.pfizer.com/news/press-release/press-release-detail/pfizer-and-biontech-conclude-phase-3-study-covid-19-vaccine

https://www.businesswire.com/news/home/20201116005608/en/

https://www.fda.gov/vaccines-blood-biologics/development-approval-process-cber/vaccine-development-101

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https://www.genome.gov/genetics-glossary/messenger-rna

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https://www.cnn.com/2020/11/20/health/pfizer-vaccine-eua-submission/index.html