Unlike many vaccines, the coronavirus vaccine being considered for approval this week by the Food and Drug Administration doesn't have a "deactivated version" of the virus in it.
The vaccine is what is called an mRNA vaccine, or messenger RNA, relatively new technology that uses genetic material to provoke an immune response.
"Unlike many standard vaccines, mRNA vaccines don’t require any deactivated version of the virus they prevent to produce – that’s a breakthrough that allows vaccines to be produced efficiently and affordably in a lab at a much faster rate than in years past," Illinois Gov. J.B. Pritzker said Wednesday.
The technology is the foundation of the Pfizer vaccine. BioNTech, Pfizer's German counterpart in the vaccine, was founded over a decade ago specifically to study mRNA technology, Pritzker noted.
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Typically, a vaccine puts a weakened or inactivated virus into our bodies to trigger an immune response, which then produces antibodies. Those antibodies are what ultimately protect us from getting infected if we ever encounter the real thing.
According to the Centers for Disease Control and Prevention, mRNA vaccines "teach our cells how to make a protein—or even just a piece of a protein—that triggers an immune response inside our bodies."
"That immune response, which produces antibodies, is what protects us from getting infected if the real virus enters our bodies," the CDC stated.
The technology has also been used in cancer research,
Pfizer's vaccine is currently the center of a Thursday meeting where independent advisers for the Food and Drug Administration will debate if evidence is strong enough to recommend vaccinating millions of Americans with the shot, which is already being administered in the United Kingdom.
The FDA is also expected to discuss a request for emergency use authorization for the Moderna vaccine on Dec. 17.
If Pfizer’s vaccine is granted an emergency use authorization by the FDA, immunizations could start as soon as next week, officials said.
Both Pfizer and Moderna built their vaccine candidates using the mRNA technology, which has never before been licensed in the U.S., but has been studied for decades.
"That we are on the precipice of the first vaccinations, just a year after this
virus was first detected, is a true testament to the quality of researchers and
epidemiologists and infectious disease doctors we have," Pritzker said.
Both companies have acknowledged that taking their vaccines could result in side effects similar to mild COVID symptoms.
UCSF Infectious Disease Specialist Dr. Peter Chin-Hong said 25-50% of 75,000 patients involved in the Pfizer and Moderna trials experienced some side effects. Fifteen percent of them were more serious and needed more than a day to recover.
“It's your body’s immune system trying to get activated because it’s seeing this new thing and the way that it gets activated is the way you’re feeling which is inflammation,” Chin-Hong said. “The virus is not in the vaccine, this vaccine is completely infection-free.”
The FDA said that while side effects of the Pfizer vaccine are common, there are “no specific safety concerns identified that would preclude issuance of an EUA.”