The FDA has authorized the Pfizer and Moderna COVID-19 vaccines for emergency use in the United States. Vaccines are crucial in saving lives and eradicating diseases caused by viruses or bacteria. Due to the wide-spread COVID-19 pandemic, the development of a vaccine to protect against the virus has progressed on extremely quickly. Here our infectious disease experts share details on how the vaccine has been developed safely and how the vaccine works in reducing your risk of contracting COVID-19.
mRNA Vaccine Science
Both the Pfizer and Moderna COVID-19 vaccines use messenger RNA (mRNA) to promote an immune response in your body to SARS-CoV‑2, the virus that causes COVID-19. Our bodies use proteins each day to keep us healthy. mRNA provides your cells with instructions on which proteins to produce, in this case antibodies to fight the COVID-19 virus. Once the instructions are recognized and our body begins producing antibodies, the cell breaks down and gets rid of the mRNA. During this process, mRNA never enters the nucleus of our cells, where our DNA is stored.
mRNA vaccine ingredients include mRNA and lipids to ensure safe delivery of the mRNA to your cells. Neither the COVID-19 Pfizer or Moderna vaccines contain adjuvants (aluminum salts) or preservatives (ethylmercury). They also do not include weakened or inactive versions of the virus sometimes found in traditional vaccinations. It is impossible to contract COVID-19 from these vaccines.
Like any vaccine, both Pfizer and Moderna’s COVID-19 vaccines have gone through clinical trials to ensure high-levels of safety. Thousands of participants received the vaccine and side effects, if any, were recorded. All four phases within the trial must be passed before moving on to the FDA approval2 process.
- Phase I: Utilizes a small group of volunteers to test the general safety of the vaccine. Adjustments are made to ensure the highest level of safety before moving on to the next phase.
- Phase II: Incorporates a slightly larger group of volunteers from a variety of demographics. Participants will receive varying doses of the vaccine to help researchers determine dosage. Short-term side effects and immune responses are recorded.
- Phase III: Vaccine is now typically administered to thousands of participants to compare immune responses between those who were vaccinated and those who received the placebo.
- Phase IIII: This final stage occurs after FDA approval. The vaccine is now available for the general public to receive. Safety and efficacy are observed on a larger scale.
For COVID-19, Emergency Use Authorization was passed since FDA approval can require ample time for licensure.
Understanding FDA Emergency Use Authorization
Before any vaccine is permitted for use in the United States, it must be reviewed and approved by the Food and Drug Administration (FDA). This process can sometimes take years, but in instances such as a pandemic, we don’t have years to wait. Emergency Use Authorization (EUA) is a tool the FDA uses to help make important medical products, such as vaccines, available more quickly during a public health emergency.
In order for the COVID-19 vaccines to be approved for use, all clinical trials must show they are safe and effective. The process follows an open and transparent review that includes input from both independent scientific and public health experts as well as FDA scientists. The known and potential benefits of the vaccine have to outweigh the known and potential risks of the vaccine in order for it to be granted EUA status. Even with quick approval, the FDA still ensures that the vaccine has met their rigorous scientific standards for safety, effectiveness, and manufacturing quality.
Pfizer and Moderna Vaccines
The Food and Drug Administration (FDA) has granted two companies, Pfizer and Moderna, Emergency Use Authorization for their COVID-19 vaccines. Both vaccines are now being distributed to the public within the United States.
They are both mRNA vaccines which work by teaching our cells how to make proteins that prompt an immune response without using a live virus. Once the immune response is triggered, our body then makes antibodies to fight the infection if the real COVID-19 virus enters the body in the future.
The Pfizer and Moderna vaccines are very similar when it comes to how safe and effective they are, however, there are a few differences:
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Who can receive the vaccine?
People 12 years and older
People 18 years and older
To be maximally effective, the Pfizer vaccine needs two doses given 21 days apart. You must receive two doses of the same vaccine.
To be maximally effective, the Moderna vaccine needs two doses given 28 days apart. You must receive two doses of the same vaccine.
Shipping, Storage & Temperature Requirements
The vaccine needs to be shipped with dry ice and maintain a temperature of less than ‑94 degrees Fahrenheit. The vials can be placed in a refrigerator for up to five days and need to be used within six hours of thawing.
The vaccine can be shipped and maintained at standard freezer temperatures of ‑4 degrees Fahrenheit. The Moderna vials can be stored in a refrigerator for up to 30 days and must be used within 12 hours once thawed.
After thawing, the vaccine has to be diluted with saline (saltwater) before it can be injected. This is a common practice for vaccines.
This vaccine does not require any dilution and comes ready to be administered.
Both Pfizer-BioNTech and Moderna COVID-19 vaccines are considered to be vaccine series, indicating the need for two doses. Researchers stress the importance of scheduling the second dose in order to have the highest protection against COVID-19. Pfizer-BioNTech recommends having two doses 21 days apart and Moderna recommends two doses 28 days apart. There is limited research on the effectiveness of patients receiving one dose of the vaccine at this time.
Between doses you can still contract COVID-19. Data has shown that vaccine participants had only 52 percent efficacy against COVID-19 after the first dose.
After the second dose, your risk of serious complications from COVID-19 infection are drastically reduced. Data has shown that it can take one to two full weeks for your body to reach full efficacy.
To protect others, experts highly recommend continuing social distancing efforts such as wearing masks after vaccination. Receiving the vaccine helps build up your immunity to COVID-19 if you are exposed. The vaccine can also help protect you from contracting serious side effects from COVID-19.
- Social distancing efforts:
- Wear a mask over your nose and mouth
- Avoid group gathering
- Stay six feet apart from others
- Wash your hands
- Wipe down commonly used surfaces
Mild side effects, such as those listed below, occur commonly and typically resolve within 24 – 48 hours of the vaccination administration. Common side effects of the COVID-19 vaccine include:
- Pain or swelling in the arm that received vaccine
These typical side effects can be treated with rest, hydration and Tylenol or ibuprofen. Patients should call their doctor if they feel that their side effects are becoming severe.
Allergic Reactions: Those with a known history of allergic reactions to injectable medications or vaccinations should consult with their primary care provider or an allergist before receiving the vaccine. The CDC recommends that patients who have an allergic reaction to the first dose of the COVID-19 vaccine should not receive the second dose. If you have questions regarding your vaccine options, please contact your primary care provider or the DMG Allergy, Asthma and Immunology department.
Onsite Safety Monitoring: All patients will be monitored for reactions to the vaccine for 15 minutes. Those with a history of severe allergic reactions will be monitored for up to 30 minutes. If you experience a reaction after leaving your appointment, seek medical attention immediately.
Follow-up Check-ins: Patients who receive the vaccine will be provided instructions on how to report side effects. A MyDMGHealth account will allow you to fill out check-in questionnaires to report any health concerns following your vaccination.
The COVID-19 vaccine may provide an opportunity for those at high risk for developing serious complications from the virus to have added immunity.
Due to limited data, it is recommended for those who are immunocompromised to consult with their primary care physician before receiving the vaccine. Your provider will help inform you about the limited data surrounding people who are immunocompromised and vaccine safety.
- Who is considered immunocompromised2?
- Cancer patients
- Those who have had a bone marrow transplant
- Those who have had a solid organ transplant
- Received stem cells for cancer treatment
- Those with genetic immune deficiencies
- Those with HIV
- Those who chronically use oral or intravenous corticosteroids or immunosuppressants