Viral vector vaccines
The COVID-19 vaccine from Johnson & Johnson is a viral vector vaccine, which uses a harmless version of a different virus, called a “vector,” to deliver information to your body's immune systems to help protect you from COVID-19.
How do viral vector vaccines work?
The vaccine teaches your body how to make copies of COVID-19 spike proteins. If you are exposed to the real virus later, your body will recognize it and know how to fight it off. The vaccine DOES NOT contain the virus that causes COVID-19 and cannot give you COVID-19. It also cannot make you sick from the virus that is used as the vector. It cannot change your DNA in any way.
Both the Pfizer/BioNTech and Moderna COVID-19 vaccines are messenger RNA vaccines – also called mRNA vaccines, and they are a new type of vaccine to protect against infectious diseases.
To trigger an immune response, many vaccines put a weakened or inactivated germ into our bodies. Other vaccines can use a particle or tiny part of the germ to trigger an immune response.
But – mRNA vaccines do not work this way. Instead, they teach our cells how to make a protein – or even just a piece of a protein – which triggers an immune response inside our bodies. This immune response produces antibodies – and antibodies are what protect us from getting infected if the real virus enters our bodies.
Have mRNA vaccines been studied?
At this time, the only licensed mRNA vaccines in the United States are the ones from Pfizer/BioNTech and Moderna. However, researchers have been studying and working with them for decades.
Interest has grown in these vaccines because they can be developed in a laboratory using readily available materials. This means the process can be standardized and scaled up, making vaccine development faster than traditional ways of making vaccines.
mRNA vaccines have been studied before for other viruses including the flu, Zika, rabies, and cytomegalovirus (CMV). As soon as the necessary information about the virus that causes COVID-19 was available, scientists began designing the mRNA instructions for cells to build the unique spike protein into an mRNA vaccine.
Future mRNA vaccine technology may allow for one vaccine to provide protection for multiple diseases, thus decreasing the number of shots needed for protection against common vaccine-preventable diseases. mRNA vaccines have also been studied for use in cancer.
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