LOUISVILLE, Ky. — Now that a third vaccine, Johnson & Johnson, is about to roll out you may have questions about the two different technologies used to administer them.
The Moderna and BioNTech Pfizer vaccines both use what's called a Messenger RNA also known as mRNA.
According to the Centers for Disease Control and Prevention (CDC), to trigger an immune response the mRNA vaccine gives instructions for our cells to make a harmless piece of what's called the "spike protein" which is found on the surface of the virus that causes COVID-19.
"In my mind it's like putting a USB in a computer and the computer sees there's a program there and it runs it," Norton Healthcare infectious diseases specialist Dr. Paul Schulz said. "One truth about [mRNA] is that we don't have as much experience with that technology versus the viral vector vaccine technology."
Viral Vector is the vaccine technology that Janssen will use – the company that owns Johnson & Johnson.
When injected, the vector will not use the virus that causes COVID-19 instead a different harmless virus will enter a cell in our body and then use it to produce a harmless piece of virus that causes COVID-19, according to the CDC.
According to Schulz, more people have been in trial for the viral vector technology compared with the mRNA, and it's been used for other vaccines like Ebola.
Schulz, who was a sub-investigator in a clinical trial for the Johnson & Johnson vaccine, said his patients have reported more side effects from the mRNA.
"And this is just anecdotally, I've had people tell me who had COVID that the side effects I had from the vaccine were similar or in their opinion worse," Schulz said. "That doesn't mean that you shouldn't get vaccinated but it does mean that some people may struggle with that."
The efficacy of Johnson & Johnson's vaccine is a lower percentage compared with Pfizer's and Moderna's. Johnson & Johnson will require only one dose, while Moderna and Pfizer both require two doses. Schulz said researchers are still learning about the difference between the number of doses.
"For the Jansen product it may be that we find out later on that that the two doses didn't significantly change the efficacy," Schulz said.
Norton Healthcare says people cannot choose which vaccine to get, but before they get their shot, they'll know which one they're taking.
"The best vaccine is the one you have the chance to get," Schulz said. "During a pandemic you don't want to be too choosey about what vaccine you get to the point that you end up delaying immunization."
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