Ask the Geriatrician: The COVID-19 Vaccine


Tim Farrell, MD
Timothy Farrell, MD
Associate Professor of Medicine and Adjunct Associate Professor of Family Medicine, University of Utah School of Medicine
Physician Investigator, VA Salt Lake City Geriatric Research, Education, and Clinical Center

The highly infectious SARS-CoV2 virus has caused the worldwide spread of COVID-19, a disease that causes mild to severe respiratory illness.  According to the World Health Organization, this worldwide pandemic has sickened nearly 100 million people and more than 2 million people have died of the disease. As of late January 2021, over 24 million people had been diagnosed with COVID-19 and more than 400,000 people had died from the virus in the United States.

In December, the Food and Drug Administration provided emergency authorization for two vaccines that proved in clinical trials to be 95 percent effective at preventing people from getting sick with COVID-19 symptoms. Already, millions of people have been vaccinated in the United States with plans on the horizon for increasing the daily number of people vaccinated.

If you feel like the news you read about the COVID-19 vaccination seems to change daily, you’re not alone. That’s why we asked Timothy Farrell, MD, a geriatrician and Associate Professor of Medicine at the University of Utah School of Medicine, about how he answers his patients’ questions. Here, he shares his expertise with us. [Click on the plus sign to open the text for each topic below.]

Vaccine Development

Q. What are vaccine trials and why should we trust them?

A. First, it’s important to understand that safety has been key to the development and approval process for COVID-19 vaccines.

Tens of thousands of people have participated in carefully designed and controlled clinical trials of COVID-19 vaccines. These trials determined how safe and effective the vaccines are. Following the completion of those trials, the U.S. Food and Drug Administration (FDA) and independent, expert advisory boards reviewed the clinical trial data to make sure that the data are correct.

Q. Who was included in the vaccine trials?

A. Currently, two vaccines have completed a phase 3 clinical trial (a late-stage trial to determine effectiveness and monitor adverse reactions in participants) and received FDA Emergency Use Authorization.

The Pfizer-BioNTech COVID-19 vaccine began a phase 3 clinical trial in late July 2020 and enrolled some 44,000 participants worldwide. Approximately 42 percent of the global participants and 30 percent of US participants have racially and ethnically diverse backgrounds. In addition, 41 percent of the global and 45 percent of U.S. participants were 56 to 85 years of age. The results of the study were consistent across age, gender, race, and ethnicity demographics.  In people over 65 years of age, the Pfizer-BioNTech COVID-19 vaccine was over 94 percent effective against COVID-19.

The Moderna Covid-19 vaccination began a phase 3 clinical trial (known as the COVE study) in October and enrolled some 30,000 US participants ages 18 and older, including those at high risk for severe complications of COVID-19 disease. The COVE study includes more than 7,000 Americans over the age of 65. It also includes more than 5,000 Americans who are under the age of 65 but have high-risk chronic conditions, such as diabetes, severe obesity, and cardiac disease, that put them at increased risk of severe COVID-19. These medically high-risk groups represent 42 percent of the total participants in the Phase 3 COVE study. The study includes more than 11,000 participants from communities of color, representing 37 percent of the study population, which is similar to the diversity of the U.S. at large. This includes more than 6,000 participants who identify as Hispanic or Latinx, and more than 3,000 participants who identify as Black or African American.  

According to the results published in The New England Journal of Medicine, people who received two doses of the Moderna vaccine, taken 28 days apart, reported no major side effects. The vaccine also proved to be 95 percent effective against COVID-19 after both doses are given. In people over 65 years of age, the Moderna COVID-19 vaccine was over 86 percent effective against COVID-19.   

**NOTE: The FDA has not yet granted the Johnson & Johnson vaccine Emergency Use Authorization. Once the FDA grants this vaccination a EUA, we will update this FAQ with information specific to this vaccine.**


Vaccine Administration

Q. How many shots do I need to get in order to be vaccinated?

A. The Pfizer and Moderna vaccines require two shots, administered 28 days apart.

Q. Will the vaccine need to be repeated? How frequently?

A. Experts don't know this yet. Since the COVID-19 virus mutates, its vaccine may be similar to flu shots in that people would need annual shots. This is still currently unknown, however.

Q.  As an older adult, which vaccine should I take?

A.  It is currently recommended that older adults take either the Pfizier or Moderna vaccine, depending on which one is available to them, since both vaccines are highly effective.  However, the second dose should be from the same manufacturer as the first dose.

Which vaccine you receive will depend on which ones are available in your community. The most important thing is that you receive any vaccine that is available to you. Receiving any of the vaccines will provide you with protection against the most serious COVID-19 symptoms.

Q. How available is the vaccine, and when can I get mine?

A. In the first phase of vaccine distribution, essential healthcare workers and nursing home residents were prioritized to receive the vaccines.

It is important to note that, while the CDC has provided national guidance for vaccine distribution (see phases below), each state has its own priority plan for vaccinations. Contact your state health department to find specific information on how to get vaccinated in your state.

Phases Distribution Groups

Phase 1a

Vaccinations are first being administered to healthcare personnel and long-term care facility residents.

Phase 1b

  • Frontline essential workers such as firefighters, police officers, corrections officers, food and agricultural workers, United States Postal Service workers, manufacturing workers, grocery store workers, public transit workers, and those who work in the educational sector (teachers, support staff, and daycare workers).
  • People aged 75 years and older because they are at high risk of hospitalization, illness, and death from COVID-19. People aged 75 years and older who are also residents of long-term care facilities should be offered vaccination in Phase 1a.

Phase 1c

  • People aged 65—74 years because they are at high risk of hospitalization, illness, and death from COVID-19. People aged 65—74 years who are also residents of long-term care facilities should be offered vaccination in Phase 1a.
  • People aged 16—64 years with underlying medical conditions which increase the risk of serious, life-threatening complications from COVID-19.
  • Other essential workers, such as people who work in transportation and logistics, food service, housing construction and finance, information technology, communications, energy, law, media, public safety, and public health.

As the availability of the vaccine increases, vaccination will expand to include more groups and the initial expansion is based on the tiers described above. In addition, since the vaccine tiers overlap, in some cases people in different phases may be vaccinated at the same time. As soon as large enough quantities of vaccine become available, the goal is for everyone to be able to easily get a COVID-19 vaccination. The federal government will actively coordinate with and support states regarding vaccine distribution. The Defense Production Act (DPA) has also been invoked in order to increase the supply of these vaccines and other tools (such as personal protective equipment) that are needed to fight this pandemic.

Q. How much will the vaccine cost?

A. The vaccine is available free of charge. The Centers for Medicare and Medicaid Services (CMS) announced that any FDA-authorized vaccine will be covered under Medicare at no cost to you. People with Medicaid and private health insurance will also receive the vaccine at no cost during this public health emergency.

BE AWARE: you may receive a phone call, text, or email promising access to the vaccine in exchange for payment. These communications are scams. Do not share personal or financial information with anyone you do not know. You cannot pay to put your name on a list to get the vaccine or get early access to the vaccine.

Q. Where can I get vaccinated?

A. The federal government is developing plans to make sure that the vaccine is widely available.  For example, experts from FEMA (Federal Emergency Management Agency) and the National Guard will assist with setting up vaccination clinics. Other strategies under consideration include mobile clinics to reach rural Americans, making vaccines available in community pharmacies, and working with primary care practices.

Vaccine Function

Q. How does the vaccine work?

A. The approved vaccines train our immune systems how to recognize and fight the virus that causes COVID-19. Sometimes this process can cause symptoms, such as fever. These symptoms are normal and are a sign that the body is building protection against the virus that causes COVID-19.

It typically takes a few weeks after vaccination for the body to build immunity (protection against the virus that causes COVID-19). That means it’s possible that a person could be infected with the virus that causes COVID-19 just before or just after vaccination and still get sick. This is because the vaccine has not had enough time to provide protection. Learn more about how COVID-19 vaccines work.

Q. Can getting vaccinated infect me with COVID-19?

A. No. None of the authorized and recommended COVID-19 vaccines or COVID-19 vaccines currently in development in the United States contain the live virus that causes COVID-19. This means that a COVID-19 vaccine cannot make you sick with COVID-19. 

Q. Will getting a COVID-19 vaccination help prevent me from getting seriously ill with the virus?

A. Yes!  The Pfizer and Moderna vaccines were 90-100% effective against getting severe COVID-19.

And, if you’re around people who are at increased risk for becoming seriously ill from COVID-19, getting yourself vaccinated may help protect them as well.

After Receiving the Vaccine

Q. What’s this “herd immunity” I keep hearing about? Does it mean I don’t need the shot?

A. No, it doesn’t. “Herd immunity” means a group of people are protected against an infectious disease because the people have all become immune to it. Either they have gotten vaccinated, or they’ve developed immunity through already having the disease. Our public health experts support achieving herd immunity through vaccination, which reduces unnecessary infections and deaths.

It’s true that if you get COVID-19 and recover, you may become immune to getting the virus again. But CDC experts say that we don’t know how long this immunity might last. What’s more, your risk for becoming severely ill with COVID-19—or dying—is far riskier than any benefits of so-called “herd immunity.” When you are vaccinated against COVID-19, you experience the benefits of immunity without getting sick.

Q. I am a member of an underserved community. What COVID-19 resources are available to me?

A. As mentioned above, if you are a Medicaid recipient, you will not have to pay to receive the vaccine. Additionally, CMS’ Office of Minority Health has a set of tip sheets for vulnerable populations, including rural residents, racial and ethnic minorities, and people with disabilities.

Q. So, once I get the vaccine, can I stop wearing a mask and end social distancing?

A. Unfortunately, no. We all must remain vigilant against the virus and continue to use all the tools available to us to help stop this pandemic, including wearing a mask over your nose and mouth, washing your hands often, and staying at least 6 feet away from others. Getting the COVID-19 vaccination and following the CDC’s recommendations for how to protect yourself and others will offer you the best possible protection from getting and spreading COVID-19. 


Last Updated February 2021