Breaking News
More () »

Answering your COVID-19 vaccine questions

We took your questions to experts such as Dr. Bill Smith, who is heading up the human clinical trials at Volunteer Research Group at UT Medical Center.

KNOXVILLE, Tenn. — Editor's Note: This story was originally published in December 2020, prior to the FDA's emergency authorization of the COVID-19 vaccine, so some older questions asked prior to the U.S. rollout may no longer be relevant. This story has been updated with several questions received in the months since, with the older questions at the bottom.

Many of you have reached out with questions about the COVID-19 vaccine

We took your questions to Dr. Bill Smith, who is leading the human clinical trials at Volunteer Research Group at UT Medical Center, as well as federal and local health experts such as the Centers for Disease Control and Prevention, the Knox County Health Department, and the Tennessee Department of Health.

Some of these answers are edited for conciseness and clarity.

Where can I find the COVID-19 vaccine?

The best resource is the CDC's VaccineFinder map tool, which lets you search by zip code to find places offering COVID-19 vaccines in your area: https://www.vaccines.gov/search/

Generally, the vaccine is now widely available everywhere in the U.S. in most major pharmacies, clinics, hospitals as well as your local health department.

As of August 17, 2021, the vaccine is currently FDA-authorized for anyone age 12 and older. Vaccine trials for children as young as 6 months old are still underway. Pediatricians said those trials have been progressing well and they are hoping FDA emergency authorization is able to be extended to them by the year's end.

What about booster shots?

Booster shots use the same vaccines as the one you originally received, so they are available in all the same places that can be found above.

The Centers for Disease Control and Prevention and FDA have authorized booster shots for all three COVID-19 vaccines as of October 21.

According to the CDC, in order to qualify for a booster shot currently, you need to fall into one of the categories below:

  • individuals 65 and older
  • residents in long-term care settings age 18 years and older
  • individuals 18-64 years old with underlying medical conditions 
  • individuals 18-64 years old who are at increased risk for COVID-19 exposure due to where they work or live (health care worker, teacher, first responder, worker/resident in congregate setting)  

People who qualify who received the Pfizer or Moderna vaccine series are eligible to receive a booster 6 months after they completed their initial series, and those who received the Johnson and Johnson vaccine are eligible 2 months after their shot. 

You do not need to receive the same shot for your booster dose, though, because the FDA and CDC also authorized "mixing and matching" on October 21, which lets people choose which vaccine they want to receive for the booster dose -- as well as switch to a different vaccine if they had an allergic reaction the one they received.

Will we need a booster every year as we do with flu shots?

While booster shots and additional shots are now authorized and recommended for people who are at greater risk to COVID-19 to provide additional immune protection, the frequency at which most people might need them in the future is still uncertain because more time is needed to observe how the virus shifts and evolves to our immune systems.

The CDC said people who are healthy, fully vaccinated and not working in occupations that put them at greater risk of catching COVID do not need a booster shot currently, saying the initial vaccines still provide robust protection against death and illness for the vast majority of people, on top of offering some protection against infection in the face of new variants.

Even if the most serious health concerns to general public health are mitigated over time through a mix of vaccines and natural immunity, boosters might be recommended in the future for healthy people -- much like flu vaccines -- if immune protection decays over time and/or COVID-19 is observed to have antigenic drift properties like the flu to regularly mutate and cause a large number of reinfections and breakthrough infections. The Delta variant has shown this is a possibility, but the frequency of these "drifts" and their ability to regularly bypass immune responses will be a key factor in determining how often booster shots would be recommended. 

"The studies that are being used for approval run two years so that we're going to continue to follow antibody levels. We're going to continue to see if there are infections that develop a year, 18 months, after vaccination. That would tell us how long these really last, so we're hopeful that particularly with some of these new technologies that they're going to last longer, but we do not have that information," Dr. Bill Smith said.

"That's why it's important to continue to enroll and participate in these studies, so that we can answer some of these remaining questions about duration, effectiveness long-term, etc."

Can you still become infected with COVID-19 after getting fully vaccinated?

Yes. "Breakthrough" infections happen with any vaccine and are expected, much like reinfections in people who have natural immunity after fighting off the virus. The chances of a vaccinated person becoming symptomatically infected are much lower than someone who hasn't been vaccinated, which is why public health is concerned with increasing vaccination rates across the board to cut off spread of a virus through herd immunity.

Even prior to the vaccine rollout, disease experts with the CDC and others said the primary goal of the COVID-19 vaccine was to provide ample protection against the most serious, life-threatening symptoms of the virus. Up to this point, the COVID-19 vaccine has been observed to be highly effective in this regard based on data on breakthrough infections.

Out of the 189 million people in the United States fully vaccinated as of October 18, the CDC reported 30,270 people (0.01%) had been hospitalized, and 10,857 (0.005%) had died due to a COVID-19 breakthrough infection. The CDC said a large percentage of the serious breakthrough cases occurred in people with compromised immune systems, which is why it is recommending them to receive a third dose of the vaccine. 

The true number of breakthrough cases not requiring hospitalization is estimated to be many times higher due to the Delta variant, but many of these cases are going undetected because people either were asymptomatic, or they had low-grade symptoms associated with seasonal colds or allergies and didn't get tested. 

The Tennessee Department of Health has said roughly 9 out of 10 hospitalizations and deaths in Tennessee during the summer surge have been in unvaccinated people. A CDC study published in mid-September compared outcomes of breakthrough infections versus people who weren't fully vaccinated, and said people who weren't fully vaccinated had substantially higher risk of dying to COVID-19 compared to someone who was fully vaccinated.

Do the current COVID-19 vaccines protect against the Delta variant?

Yes, but early data shows the doubly contagious Delta variant has led to an large increase in breakthrough infections in the fully vaccinated, and that it has become the predominant strain across most the U.S. as of mid-August -- making up nearly 82% of all new COVID-19 infections currently based on the CDC's weekly genomic sequence sampling conducted across the U.S.

Early studies conducted on the currently authorized vaccines show they continue to provide robust protection against serious illness when it comes to the Delta variant. The Pfizer-BioNTech was 88% effective against preventing symptomatic illness and 96% effective against preventing hospitalization specifically with the Delta variant. Moderna studies reported similar effectiveness at around 76% at preventing symptomatic infection, and Johnson and Johnson's vaccine showed to be 71% effective against hospitalizations and up to 95% against death. 

If you have had COVID-19, do you still need a vaccine? Would it be safe for a person in that situation to take the vaccine?

"Yes. The most current recommendations from the CDC and public health authorities is for people to go ahead and be vaccinated when it's available to their group.

There seem to be no negative consequences of vaccinating someone who has had COVID-19 previously from looking at the data of the vaccine studies that are being evaluated. So for now, the answer is yes. 

As with many things around COVID-19, this could change, but it won't change because of safety. It would change because of a better understanding of the immunity you would get from an infection," Dr. Bill Smith said.

We do know about common side effects shortly after the vaccine is administered, but what about months, years down the road?

"Well, we don't have any data for months or years down the road, but the information we have from other vaccines and from the limited data that we've got with these vaccines would suggest that most if not all of the side effects occur early on after the injections and that long term risks are minimal. And when you compare those risks with the risk of having a COVID infection, the risk/benefit ratio is overwhelming," Dr. Bill Smith said.

Three years ago, after receiving the flu vaccine for 25 years, I had a severe reaction and was told to never get it again for the rest of my life. How will this affect me for receiving the COVID-19 vaccine when it becomes available to the general public?

"The Moderna and Pfizer vaccines are totally different technology, totally different ingredients, and there should be no crossreactivity. The Janssen vaccine that will probably be approved early next year is also new technology that would not have cross-contamination from prior technologies. So for many of these vaccines, you are going to be fine. 

This is really a question though that ultimately you should discuss with your family physician and make that decision jointly."


When the vaccine is ready to be given to people other than healthcare workers, how long will it be before people who are immunocompromised can get a shot?

"That will be determined by the criteria the CDC and other government agencies establish for distribution. Based on the criteria that have been circulated from the U.K., it looks like you would be somebody that would be in the second or third tier, which means very early in the process. 

Your age would be another determining factor. That is also one of the criteria as well as underlying illnesses that help to determine priority."

WHO GETS IT FIRST?: Panel recommends health care workers, long-term care residents get COVID-19 vaccine first

When do you foresee the vaccines arriving in East Tennessee?

"The best guess right now, if everything went the way that everyone is hoping, the FDA will rule on the 10th, and we would have the vaccine on the 11th."

VACCINE TRIALS: Answering your COVID-19 vaccine trial questions

Will people get to choose which vaccine they get if there are multiple ones approved and how do those recommendations work with a physician?

"Initially, at least, there are going to be limited supplies of the vaccines, so people will be advised to take whatever is available when their group priority will allow them to get a vaccine. 

Any of the vaccines that are going to be approved are going to be effective and waiting on one or the others for a slight difference in percentage really is not realistic.

The key message that needs to be emphasized in this is there have been no serious cases of COVID-19 infections in people that have received the injections, and there have been no deaths. 

Even if you were to get COVID-19, there is every reason to believe you're going to have a much milder case, and that you're going to be much better off than if you weren't vaccinated at all."

JUST GET ONE: VERIFY: Can you take both COVID-19 vaccines? Why experts say to stick with just one

TRIALS IN KNOXVILLE: Breakthrough COVID-19 vaccine has Knoxville ties

RELATED: Knox County hospitals begin experimental antibody treatment for some COVID-19 patients

When will a healthy, younger adult be able to get the vaccine?

"We don't know. This is being controlled by the government, primarily through CDC, state and local health departments. There will be guidelines that will be published soon.

The younger and healthier you are, the later in the process you are going to get vaccinated. So if you are young and healthy, the quickest way to get a vaccine is to do one of the vaccine trials."

Earlier in the pandemic, there was a theory about certain blood types possibly being immune or resistant to COVID-19, has that proven to be true and how does that apply to who should have the vaccine?

"That does not influence at all who should have the vaccine. Everyone should have the vaccine when the vaccine is available for their risk group.

It does appear that blood type O may have a lower infection rate and less severe infections. It may appear that types A and AB have a higher risk of infection and severe infections. This was early data, but it really hasn't changed. However, it doesn't mean that you're safe or doomed."

BLOOD TYPES AND COVID-19: VERIFY: Research on blood types and COVID-19 severity show contradictions

Are they going to put a tracker chip in the vaccines to keep up with us?

"No. There are many of these internet stories that are being published by the anti-vaxxers, but no, there are no chips in the vaccines. We don't have transmitters that are that good to where they could do it even if they wanted to, but absolutely not."

What assurance is there that there aren't any long-term side effects or dangers since it was rushed in development?

"Safety in every possible way has not been compromised. The shortcuts that have been taken have been on the regulatory side in terms of the way that the data is requested and the parts of the data that are being looked at. All the safety data is being reviewed.

Some of the secondary data that answers other questions about the vaccine is still being collected but is a long way from being reviewed or published. 

The other part of the process that has been dramatically shortened is related to financial risk. That risk was mitigated or totally eliminated by Operation Warpspeed, where the government covered certain costs in developing the vaccines, so companies did not have to wait in assessing both the safety and financial risk to get to the large studies."

How significant is the FDA giving the Pfizer vaccine emergency use authorization?

"This is extremely significant because it will allow Pfizer to begin shipping vaccine and it to be given to large numbers of people on an expedited basis. Tennessee is part of their early rollout, so we will be as early as anyone beginning to get these injections."

The UK is a little bit ahead of us and has started administering the Pfizer vaccine. As a result, there have been several cases...a couple of cases of severe allergic reaction. Was this expected, or just how rare is it for this to happen in a case like this?

"This is not something that happens very commonly. And the information that is now being made available indicates that both of these people who had these allergic reactions had significant history of severe allergic reactions. They both carried Epipens, which are self-administered to treat severe allergic reactions. So in these individuals, it may not have been expected, but by the same token, it isn't unexpected, and it's not generalizable to the general public. People that have typical allergies should not be worried about taking these vaccines at all."

Before You Leave, Check This Out