Can Your Second Dose Of COVID Vaccine Be Different From Your First?

WBZ-TV's Dr. Mallika Marshall answers your COVID questions.

Video Transcript

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- Even a year into this, there are still a lot of questions and concerns as we navigate the coronavirus pandemic. And many of you have been reaching out to our Dr. Mallika Marshall with your questions. And we want to get to some of those today. Dr. Mallika joins us now. Doctor, want to get to the very first question, which is from Mary. And she writes, "I was administered the Moderna vaccine for my second dose. However, my first dose was Pfizer. Can you tell me if you are aware of the side effects of interchanging the two? This was a mistake by the nurse who gave the shot."

MALLIKA MARSHALL: Yeah, so ideally you want to stick with the same manufacturer. If you get your first dose from Pfizer, your second dose should be a Pfizer dose as well. But sometimes that is impossible or sometimes mistakes are made, like in your case. And even though we don't think that that's going to cause you any harm, you know, they're so similar that the chances are, even if you get one dose of one and one dose of the other, you're still going to be very well protected.

- And a lot of people haven't had the shots yet. Tracy writes, "I'm really on the fence about getting the shots. I am really allergic to garlic. My body can't handle the protein in it. It's my understanding that the vaccine has a protein in it. Will my body try and fight it and make me sicker than normal?"

MALLIKA MARSHALL: Well, you know, there are proteins-- numerous proteins in our bodies and out in nature. And just because you're sensitive to one protein or have an allergy does not mean that you're going to have an allergy to another one. So we know that people with food allergies can safely get vaccinated against COVID-19. And I'm really hoping that you are going to consider getting vaccinated, because it could save your life or could save the life of a loved one. But you can talk to your doctor about your concerns.

- And Dr. Janice is going to be getting the shot. She writes, "I'm scheduled to get the vaccine. After I get the vaccine, is my husband supposed to wear a mask in the house because he didn't get the vaccine yet? My husband heard that somewhere."

MALLIKA MARSHALL: No, not at all. The vaccine is not going to give you the coronavirus. So you're not going to get vaccinated and then be able to pass the virus on to someone else. Your husband and you only need to take precautions if one of you actually got infected with the coronavirus.

- Well, here's a question that I think a lot of people probably started asking during the pandemic. Another viewer says she was diagnosed with COVID-19 and writes, "When is your oxygen too low? When should I go to the ER?"

MALLIKA MARSHALL: This is a great question. And especially people who are at higher risk of severe COVID-19, they really should be trying to monitor their oxygen saturation level at home, which you can do easily with a little probe that you put on your finger. It's completely painless. Normal oxygen saturation is 96% or above. If you find that your oxygen level is dropping below 94%, 93%, then it's time to call your doctor.

- And those little tools you describe, they fit right on the end of your finger, they're really inexpensive, and they're really important. Dr. Mallika Marshall, thank you so much. Dr. Mallika offers her best advice, but as always, consult your personal doctor before you make any decisions about your health. If you have a question for Dr. Mallika, there are three ways to reach her. Email dr.mallika@cbs.com, on Twitter @mallikamarshall, or you can also Facebook message her, Dr. Mallika Marshall.