How does Moderna’s vaccine compare to Pfizer’s?

COVID-19 Vaccine
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DENVER (KDVR) — Most people like to have options, especially when it comes to health care. But when it comes to COVID-19 vaccines, Coloradans have limited options for the time being. 

The first Coloradan was vaccinated Monday, and Moderna’s vaccine is expected to receive Food and Drug Administration approval by the end of the week, with a hearing on Thursday.

“There are more similarities than there are differences,” said UCHealth Chief Clinical Research Officer Dr. Thomas Campbell. 

Campbell was heavily involved in Moderna’s trial in Colorado, and said there was a high interest in participation, which greatly helped. Ironically, he says the prevalence of COVID-19 in the community helped vaccine trial results come in faster, since the placebo subjects were more likely to catch the virus.

“It did not take long for the study to reach the number of COVID cases necessary to measure a difference between the placebo and the vaccine group,” Campbell said. “The answer was reached much faster than anybody would have anticipated.”

When comparing the two vaccines, Campbell says there are more similarities than differences.

It starts with how the two vaccines use a different method to combat the virus. Traditionally, vaccines inject a protein from the virus into your body, so your immune system recognizes it and learns how to fight it. Usually, that protein needs to be developed in a lab.

The Pfizer and Moderna vaccines use mRNA to instruct your body to create the protein. 

“The spike protein doesn’t have to be made in the laboratory, it’s instead made in our bodies,” Campbell said. 

Pfizer’s efficacy rate is 95% while Moderna’s vaccine sits at 94.5%. Pfizer’s is approved for people over the age of 16 and Moderna’s for 18 and older. Each vaccine also requires two shots, but Pfizer’s requires 21 days in between, while Moderna’s requires 28 days. 

The side effects, which are both reportedly mild or moderate, can include soreness, headache and muscle pain for both vaccines.

“The side effects are very similar,” Campbell said. “They both produce similar levels of what we call ‘injection reactions.'”

One big logistical difference is how they are stored. Pfizer’s vaccine requires the ultra-cold freezers to keep the doses stable. Moderna’s don’t require that kind of storage.

Colorado’s Department of Public Health and Environment tells the Problem Solvers there are 16 sites across the state that have ultra-cold freezers to store the Pfizer vaccine. Since Moderna’s vaccine can remain stable without those freezers, CDPHE expects that vaccine to be more broadly used across the state.

The supply chain is another factor in how widely available each vaccine will be. 

So far, the United States has secured 100 million doses of the Pfizer vaccine, and 200 million doses of Moderna vaccine, after purchasing an additional 100 million last week, according to Axios.

Since distribution of vaccines from the Centers for Disease Control to the states is done proportionally, it would seem Colorado, and every other state, could see twice as many Moderna vaccines than Pfizer doses.

“There’s no need to fret about one or the other, whichever one you’re offered, just go ahead and take it. It’s important that we get immunized as soon as possible,” Campbell said.

While those two vaccines are the first in line for approval and distribution across the country, there are 59 other vaccines in clinical trials across the world, and 16 in stage 3 clinical trials. 

AstraZeneca, Johnson and Johnson, and Novavax are all in that stage, and have received money from the federal government as a part of Operation Warp Speed. 

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