Misconceptions such as thinking COVID-19 vaccines can alter DNA or infect a person with the coronavirus can fuel vaccine hesitancy, but it may help to understand how the vaccines work in order to dispel these myths.
Vaccines teach the immune system to fight disease by creating antibodies. The same process occurs during a natural infection, but vaccines are superior in that patients gain protection against a disease without risking serious illness, also preventing spread of that serious illness to others.
The three COVID-19 vaccines available in the U.S. work differently than many other well-known vaccines, in part because researchers have been studying and developing these newer methods for decades in order to create vaccines that are easier to scale up and reproduce in the case of an epidemic.
Anti-vaccine groups have used the newness of these technologies as one way to spread misinformation and sow fear among the public.
How do the vaccines work?
Answer: COVID-19 vaccines train the body to recognize the hallmark protein on the surface of the coronavirus that resembles a "spike" or a crown.
Dr. John Mascola, director of the Vaccine Research Center at the National Institute of Allergy and Infectious Diseases, said during an American Association for the Advancement of Science webcast that many well-known vaccines — such as influenza and hepatitis B — are protein-based vaccines, in which "one makes the subunit or a part of the virus completely safe and innocuous so that it doesn't contain any live viral parts."
"That protein can be injected into muscle, teach the immune system to recognize that form of protein. The immune system makes antibodies and other responses, and that helps protect a person," Mascola said.
Novavax, a biotech company based in Maryland, has been testing a protein-based COVID-19 vaccine and announced recently its two-shot vaccine was about 90 percent effective, and preliminary data showed it was safe. For those who may prefer that type of shot, the Associated Press reported Novavax plans to seek authorization for the vaccine in the U.S. by the end of September.
But for now, the three COVID-19 vaccines available in the U.S. — made by the companies Pfizer, Moderna and Johnson & Johnson — contain genetic instructions for the body to make its own spike protein.
Both the Pfizer and Moderna vaccines are messenger RNA or mRNA vaccines, meaning their active ingredient is a single-stranded RNA molecule containing instructions for cells to make a harmless spike protein resembling the protein on the surface of the coronavirus.
Johnson & Johnson's COVID-19 vaccine is a "viral vector" vaccine. In this vaccine's case, an adenovirus, which is a virus family that causes the common cold, has been modified to the point it's harmless, and adenovirus acts as the "vector" to transport the genetic information for the spike protein.
"Rather than deliver the protein itself, the body makes the protein. But the result is the same. The immune system makes antibodies, and those antibodies can block the virus," Mascola said.
Other types of vaccines that exist include inactivated or live weakened viruses and DNA vaccines, but no COVID-19 vaccines in the United States use these methods.
In the case of the Pfizer and Moderna vaccines, once the shot is given in the upper arm, the mRNA is transported to the immune cells, which make the spike protein.
"After the protein piece is made, the cell breaks down the instructions (mRNA) and gets rid of them," according to the U.S. Centers for Disease Control and Prevention website. "Next, the cell displays the protein piece on its surface. Our immune systems recognize that the protein doesn't belong there and begin building an immune response and making antibodies."
Although the mRNA vaccines deliver genetic material to our cells, the CDC states "the material never enters the nucleus of the cell" — which is where our DNA is stored.
"This means the genetic material in the vaccines cannot affect or interact with our DNA in any way," the CDC states.
In the case of Johnson & Johnson's vaccine, the "vector" — which is a harmless adenovirus — enters a cell and uses its "machinery" to produce a spike protein.
"The cell displays the spike protein on its surface, and our immune system recognizes it doesn't belong there. This triggers our immune system to begin producing antibodies and activating other immune cells to fight off what it thinks is an infection," the CDC states. "The genetic material delivered by the viral vector does not integrate into a person's DNA."
Since none of the vaccines authorized for use in the United States contain a live virus, that also means that they can't cause someone to get COVID-19 or cause "vaccine shedding."
"Vaccine shedding is the term used to describe the release or discharge of any of the vaccine components in or outside of the body," according to the CDC. "Vaccine shedding can only occur when a vaccine contains a weakened version of the virus."