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Vaccines help prepare the body to fight foreign invaders (pathogens such as
bacteria or viruses), to prevent infection. All vaccines introduce into the
body a harmless piece of a particular bacteria or virus, triggering an
immune response. Most vaccines contain a weakened or killed bacteria or
virus. However, scientists have developed a new type of vaccine that uses a
molecule called messenger RNA (or mRNA for short) rather than part of an
actual bacteria or virus. Messenger RNA is a type of RNA that is
necessary for protein production. In cells, mRNA uses the information in
genes to create a blueprint for making proteins. Once cells finish making a
protein, they quickly break down the mRNA. mRNA from vaccines does not enter
the nucleus and does not alter DNA.
mRNA vaccines work by introducing a piece of mRNA that corresponds to a
viral protein, usually a small piece of a protein found on the virus’s
outer membrane. (Individuals who get an mRNA vaccine are not exposed to the
virus, nor can they become infected by the vaccine.) Using this mRNA
blueprint, cells produce the viral protein. As part of a normal immune
response, the immune system recognizes that the protein is foreign and
produces specialized proteins called antibodies. Antibodies help protect the
body against infection by recognizing individual viruses or other pathogens
, attaching to them, and marking the pathogens for destruction. Once
produced, antibodies remain in the body, even after the body has rid itself
of the pathogen, so that the immune system can quickly respond if exposed
again. If a person is exposed to a virus after receiving mRNA vaccination
for it, antibodies can quickly recognize it, attach to it, and mark it for
destruction before it can cause serious illness.
Like all vaccines in the United States, mRNA vaccines require authorization
or approval from the Food and Drug Administration (FDA) before they can be
used. Currently vaccines for COVID-19, the disease caused by the SARS-CoV-2
coronavirus, are the only authorized or approved mRNA vaccines.
These vaccines use mRNA that directs cells to produce copies of a protein on
the outside of the coronavirus known as the “spike protein”.
Researchers are studying how mRNA might be used to develop vaccines for
additional infectious diseases. |
