As health care professionals administer COVID-19 vaccines throughout the United States, many people have questions, including who is being vaccinated first and how the vaccines work. Here are answers to some frequently asked questions about the vaccines, including additional insight from Armando Meza, M.D., chief of infectious diseases at the Texas Tech University Health Sciences Center El Paso Foster School of Medicine.

No. The Pfizer and Moderna vaccines do not contain live versions of the COVID-19 virus. Other early COVID-19 vaccines, including AstraZeneca’s and one being developed by Johnson & Johnson, do not contain the live virus either.
Though there is no known timespan for the vaccine’s effectiveness, Dr. Meza estimates the vaccine’s protection will likely last at least one year, if not longer.

Yes. Currently, there’s no firm data on how long immunity lasts after a patient is infected with COVID-19. Because re-infection is possible, the vaccine is suggested for further protection.

Per the CDC, Pfizer, Moderna and the Texas Department of State Health Services, below are more answers to frequently asked questions about COVID-19 vaccines.

The FDA authorized two vaccines for emergency use authorization in December. The Pfizer and BioNTech vaccine (commonly referred to as the Pfizer vaccine) was authorized by the FDA on Dec. 11, 2020.  The Moderna vaccine was authorized by the FDA on Dec. 18, 2020. For maximum effectiveness, the vaccines are administered in two doses: 21 days apart for the Pfizer vaccine and 28 days apart for the Moderna vaccine.

It varies from state to state. In El Paso, the vaccine is being administered in phases recommended by the Texas Department of State Health Services. Those in Phase 1 are currently being vaccinated.

Phase 1, Group A includes:

  • Physicians, nurses, first responders and other health care personnel essential to keeping the health care system intact.
  • Emergency medical services.
  • Residents and staff at long-term care facilities.
  • Urgent/community clinic personnel.
  • School nurses.

Phase 1, Group B includes:

 

  • People 65 years of age and older.
  • People 16 years of age and older with at least one chronic medical condition that puts them at increased risk for severe illness from COVID-19, including:
    • Cancer
    • Chronic kidney disease
    • Chronic obstructive pulmonary disease (COPD)
    • Heart conditions, such as heart failure, coronary artery disease or cardiomyopathies
    • Solid organ transplantation
    • Obesity and severe obesity (body mass index of 30 kg/m2 or higher)
    • Pregnancy
    • Sickle cell disease
    • Type 2 diabetes

 

Phase 2 is expected to begin in Spring 2021, but the date is dependent on vaccine production and how quickly vaccines become available, according to the Texas Department of State Health Services. The Expert Vaccine Allocation Panel (EVAP) is currently considering criteria to be used for distribution during this phase.

For the Pfizer vaccine, the most common adverse reactions reported were temporary, mild pain at the injection site, fatigue and headache. These side effects generally resolved within two days, according to Pfizer’s large-scale study of more than 40,000 participants. These reactions were less common and milder in older adults than younger adults.

There have been reports of allergic reactions in a handful of people who were vaccinated with the Pfizer vaccine in Britain and Alaska. The FDA has issued a precaution for people with a history of severe allergic reaction to vaccines; they may still receive the vaccine, but health care workers should counsel them on the risks and benefits of receiving the vaccination.

The Moderna study found that most common side effects were mild and included injection-site pain, fatigue, headache and chills. Severe adverse reactions were rare but occurred more frequently after the second dose.

For maximum effectiveness, the vaccines require two doses: 21 days apart for the Pfizer vaccine and 28 days apart for the Moderna vaccine.

The FDA and CDC recommend that those vaccinated for COVID-19 continue wearing masks in public, maintain a social distance of six feet from others and wash hands frequently.

Continued mask wearing will help ensure the safety of others as the vaccine rollout continues through 2021, according to Dr. Meza. “At this point, it’s not completely clear that you’re not going to be infectious to other people, even after being vaccinated,” he said.

The Pfizer and Moderna vaccines are known as mRNA vaccines. They have strands of genetic material called mRNA inside a special coating. That coating protects the mRNA from enzymes in the body that would otherwise break it down. It also helps the mRNA enter the muscle cells near the vaccination site in the upper arm.

The vaccines give instructions for our cells to make a harmless piece of what is called the “spike protein.” The spike protein is found on the surface of the virus that causes COVID-19.

Once the instructions (mRNA) are inside the immune cells, the cells use them to make the protein piece. After the protein piece is made, the cell breaks down the instructions and gets rid of them.

Next, the cell displays the protein piece on its surface. Our immune systems recognize that the protein doesn’t belong there and begin building an immune response and making antibodies, like what happens in natural infection against COVID-19.

At the end of the process, our bodies have learned how to protect against future infection. The benefit of mRNA vaccines, like all vaccines, is those vaccinated gain this protection without ever having to risk the serious consequences of getting sick with COVID-19.

They are new, but not unknown. Researchers have been studying and working with mRNA vaccines for decades. Interest has grown in these vaccines because they can be developed in a laboratory using readily available materials. This means the process can be standardized and scaled up, making vaccine development faster than traditional methods.

Future mRNA vaccine technology may allow for one vaccine to provide protection for multiple diseases, thus decreasing the number of shots needed for protection against common vaccine-preventable diseases.