Here's a list of how the Moderna & Pfizer vaccines compare

Health experts are on the verge of possibly having two COVID-19 vaccines and ABC13 has learned how the two compare.

SEE RELATED STORY: US COVID-19 vaccinations ramp up as Moderna shot nears authorization

According to the FDA, the Moderna vaccine was 94.1% effective at preventing symptomatic cases. The Pfizer vaccine has claimed 95% effectiveness.

Both vaccines require two doses, however. For those receiving the Pfizer vaccine, the second dose is administered 21 days after the first. Moderna's second dose is administered 28 days after the first.

They both also developed the messenger RNA, a new type of vaccine that creates a blueprint for those essential antibodies, without actually infecting people with COVID-19.

They differ once again in how they are stored.

Pfizer's needs to be stored at 94 degrees below zero. After it thaws, it can be stored in a normal fridge for five days.

Moderna's vaccine still needs to be kept cold, but rather at a standard freezer temperature, negative four degrees. After it thaws, it can be refrigerated for 30 days.

Pfizer's vaccine was authorized for people ages 16 and up. Moderna's vaccine was recommended by an FDA panel for emergency-use authorization for people 18 and older.

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The side effects seem to be the biggest thing on people's minds. So far minor temporary side effects like tiredness and headache have been reported by the CDC.

Here's a full list of possible side effects that both vaccines can have on people:

• Pain at the site of injection

• Headache

• Fever

• Fatigue

• Chills

• Muscle and joint pain

The difference is that the Moderna vaccine's side effects were found to be more common after the second dose. Either way, health experts said people may want to consider taking the day off work after getting the second shot.

There are still some areas we need to learn more about. For example, how the vaccine works in children and in pregnant women. Many are also wondering if you can choose which vaccine to get.

ABC13 spoke with a Baylor College of Medicine infectious disease professor.

Dr. Jill Weatherhead said it's very unlikely people will get to choose which vaccine they get because it'll depend on which is available in their area.

Vaccines must not be mixed and matched.

On Tuesday, the first Houston nurses and doctors received a card showing which vaccine they took. Others are likely to get something similar, so it can be presented when receiving the second dose.

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