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Moderna vaccine vs Pfizer vaccine

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TUCSON (KVOA) - As the vaccines roll out, so do questions and concerns. Do they work? What are the side effects? Which one is more effective?

Pfizer or Moderna? Different companies but both said to be 95% effective. Doctors all over the world are saying, not just having one but two vaccines is incredible.

"People say to me, which vaccine would you take? I say the one where the syringe is closest to my arm."

Dr. Elizabeth Connick, the UArizona Chief of the Division of Infectious Diseases, called the vaccine a home run.

"These are some of the most biggest accomplishments in medicine in the last 25 years."

Overall, Dr. Connick said, the same vaccine but there are a few differences, like effects.

"Preliminarily, it does seem like the Moderna causes more side effects. More fatigue and particularly after the second dose. But it could be because you are getting a great immune response."

The dosage is different, as well.

"The Pfizer vaccine requires the second dose on day 21 after the first dose. The Moderna vaccine requires it to occur at day 28. I do not really think that makes a huge difference."

But, a major difference between the two, storage.


"It can be stored at -20°C and it can last in a refrigerator for up to 30 days."


"The Pfizer vaccine on the other hand requires really deep freeze, -70°C storage and it can only be in room temperature for five days."

"The science is solid behind vaccines. Vaccines work. They are safe and effective," said Arizona Department of Health Services Director Dr. Cara Christ.

On Wednesday, Dr. Christ rolled up her sleeve and got the coronavirus vaccine.

"As I was watching other people get the shot, I was like I do not want to get poked because I have been terrified of it {needles} since I was little. I did not even feel it go in, that is how good it was."

It has been 24 hours since getting the Pfizer vaccine. News 4 Tucson asked if she had any side effects.

"Today, I have a little bit of pain at the injection site but that is normal for me. I get that way with my annual flu shot."

As the vaccines are now in Tucson, Dr. Christ has a message she wants you to hear.

"The vaccines are very safe and we want to make sure every Arizonan knows they should go get this vaccine when it is their turn."

There are still some unanswered questions, like how does it affect kids and pregnant women? The best option is to talk to your doctor.

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Allie Potter

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