Contributed Photo / Dr. Paul Hendricks

Answers to some of your most common COVID-19 questions.

Q: I still keep hearing scary things online about the vaccine. How have things been going overall?

A: The experiences with the first two vaccines released for emergency use by the Food and Drug Administration have been very reassuring. The vaccines continue to be very safe. The biggest concern has been related to a few allergic reactions that have occurred. However, these have been very rare. Out of the first nearly 1.9 million doses given of the Pfizer vaccine, there were only 21 cases of anaphylaxis, a severe allergic reaction. All of those people affected were treated and survived. These reactions nearly always occur within 30 minutes, which is why it is so important to remain at the vaccine site for a period of time after your shot. We are prepared with appropriate emergency treatment in the event of such a reaction to the vaccine, but so far there have been no episodes locally. The only real contraindications to the vaccine are if you have a known severe allergy to any of the ingredients in the vaccine or to a previous dose of the vaccine.

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Q: How can I find out what's in the vaccine so I'll know if there's anything I'm allergic to?

A: The ingredients of each vaccine are similar and can be found at the website. For the Pfizer vaccine they can be found at, and for the Moderna vaccine look for Also, when you come to get the vaccine you will be provided with a list of the ingredients. You will receive a record card with your vaccine that says which manufacturer's product you received. It is very important that your second dose is by the same manufacturer as your first dose.

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Q: Can I still be tested for COVID-19? Will the results be accurate?

A: Yes, the current vaccines available or being developed do not affect the results of tests for acute COVID-19, either the antigen tests or the PCR (polymerase chain reaction) tests. However, since the goal of the vaccine is to stimulate your immune system, you may have a positive antibody test from the vaccine.

Q: Someone told me the vaccine can change my DNA. Is that true?

A: No, it's not. The vaccine has a small piece of genetic material called messenger RNA (mRNA) that tells your cells to create a protein to stimulate your immune system to fight the virus. This mRNA does not enter the nucleus where your DNA is and cannot affect it at all. Think of it this way: If you get a gift from your mother for Christmas that is wrapped and packed in a box for shipping and she puts a note inside the box saying, "Do not open until 12/25," you can read the note without ever opening the gift. Messenger RNA works like that: The message (mRNA) never enters the gift (your cell's nucleus).

Q: Can I get sick from the vaccine?

A: There are certain side effects that are fairly common, but you will NOT get COVID-19. There is no coronavirus in the vaccine, either alive or dead. So, while you may have some muscle aches with chills and fatigue or a sore arm, you won't actually get an infection from the vaccine. Usually these side effects occur within a few days after the shot, but some have reported them a week or two later. They should go away within a few days, but if they last longer or seem particularly severe you should check with your doctor.

It is important to remember that everything we do in medicine has risks, but so do the diseases we treat. So far the COVID-19 vaccines appear to be remarkably safe and effective at protecting people, and I urge everyone who can to get it.

Paul M. Hendricks, M.D., is the Hamilton County health officer and a member of the Chattanooga-Hamilton County Medical Society.