Commonly Asked COVID19 Vaccine Questions — Answered
November 02, 2021
Commonly Asked COVID19 Vaccine Questions — Answered
Man receiving shot in arm

Allison Liddell, M.D., Infectious Disease

Allison Liddell, M.D., the chief of infectious disease at Texas Health Presbyterian Hospital Dallas, is admittedly a big proponent of the COVID-19 vaccines. Liddell is such a big proponent that she was among the first in line to get the Pfizer vaccine when it arrived at the hospital almost a year ago.

“I think all the safety precautions are important, but you cannot perfectly social distance and mask the entire planet for as long as we would need to in order to get rid of this,” said Liddell, a physician on the hospital’s medical staff and a member of Texas Health Physicians Group. “We have to have something else, and I think the vaccine is that other part. The vaccine gives us the edge that we need to help better control the pandemic.”

Below, Liddell debunks some of the vaccine myths she’s heard in her own words:


Myth: The vaccine will affect or alter my DNA

Dr. Liddell: “This is false. Messenger RNA, a molecule that we all have in our bodies, is like a recipe that tells our body how to make the proteins that we need. COVID-19 mRNA vaccines, such as the Pfizer and Moderna vaccines, don’t go anywhere near your DNA or affect it at all.

It just tells your natural little protein factories in your cells — your ribosomes — how to make this protein so your immune system can react against it. It’s a very simple, elegant, really cool vaccine that is designed to be safer than vaccines in the past, which often were live vaccines.”


Myth: The vaccine side effects are severe.

Dr. Liddell: “The vaccines have a very low rate of serious adverse reactions. Side effects are more common after the second dose because your body is already primed for that protein that’s being made so it reacts to it a little more and that’s just a sign that your immune system is working. And the side effects that do happen, they happen within a day or two. They don’t happen weeks later or months later. There is no evidence that there are any long-term side effects from this vaccine.”

For Liddell personally, the side effects were minimal.

“I personally had some fever for about 24 hours and just kind of general achiness after the second dose and I took some Advil and was fine and able to work. I do know some people who felt bad enough to not work the day after but that was all temporary, and in my opinion, 100% worth the incredible effectiveness of the vaccine.”


Myth: COVID-19 vaccine boosters are a higher dosage than the original vaccine.

Dr. Liddell: Boosters are administered to boost your immunity back to its original effectiveness, but none of the COVID-19 boosters are higher doses than the original doses. A booster shot is an additional dose of a vaccine that you’ve already received in order to increase your protection against a virus or disease. Vaccine protection wanes slightly over time, which is why you may need to get a booster shot, similar to an annual flu shot or a tetanus shot every 10 years.”

A booster of the Pfizer and Moderna COVID-19 vaccines has been approved for the following individuals:

The Pfizer and Moderna boosters should be given six months after the second dose.

The Johnson & Johnson COVID-19 booster has been approved for individuals 18+ and should be given at least two months after the first dose.

Moderna’s booster has been cleared by the FDA for half the original .5 mL dose, while both Pfizer and Johnson & Johnson’s boosters will be equivalent to one full dose.

Additionally, the boosters are not made up of already mixed doses of different vaccines, such as Johnson & Johnson and Moderna, however, the CDC says it is OK to receive a different booster from the vaccine you originally received based on preference or availability.


Myth: The COVID vaccine is being mixed with the flu vaccine.

Dr. Liddell: “Not at this time. If you’d like to receive both vaccines, you’ll have to receive two shots — one of the COVID vaccine and another of the flu vaccine.

It’s safe to get your flu shot and COVID vaccination during the same visit, although to reduce soreness, the CDC recommends receive each shot in different arms. Getting several vaccinations at once has been standard medical practice for decades, and these combos have never caused any harm.”


Myth: The flu vaccine will protect against COVID. 

Dr. Liddell: “This myth piggybacks off the previous myth, where, as of right now, the current flu vaccine will not protect you from COVID-19 because it was created to only protect against the flu. The only vaccine that will provide protection against COVID-19 are COVID-19 vaccines.”


Myth: If I get the COVID-19 vaccine, I am no longer at risk for contracting the virus and no longer have to take safety precautions like wearing a mask.

Dr. Liddell: “If you get this vaccine, you are very unlikely to develop severe COVID, but you can still potentially get COVID. The vaccine may not prevent mild asymptomatic infections, so it’s important to keep masking and social distancing so you don’t inadvertently give the virus to an unvaccinated friend or family member.

“We can’t ease up on prevention until the vast majority of people are vaccinated and the number of cases in our community is way down. This is our chance for all of us to come together to rid us of this pandemic, of which we are all so sick.”


Myth: The vaccine is not safe during pregnancy and will cause infertility.

There is currently no evidence that the vaccine causes any problems with pregnancy.

Additionally, the CDC indicates that there is currently no evidence that any vaccines, including COVID-19 vaccines, cause fertility problems in women or men.


Myth: Getting a COVID-19 vaccine can make you magnetic or will implant a microchip in your body.

COVID-19 vaccines will not make you magnetic because they do not contain ingredients that can produce an electromagnetic field, according to the CDC. All COVID-19 vaccines are free from metals.

Similarly, the COVID-19 vaccine does not contain any microchips or any other tracking or electrical devices. Vaccines are developed to fight against disease and are not administered to track your movement.

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