At this time, the Pfizer vaccine is the only vaccine authorized for use in teens ages 16 and older and children ages 12-15 to prevent COVID-19. It is administered in two doses three weeks apart, injected into the arm muscle.
The Pfizer vaccine, as well as the Moderna vaccine, which is authorized for people ages 18 years and older, is an mRNA vaccine. When the vaccine is injected, mRNA – a strip of genetic material – enters a body’s cell and prompts the cell to build copies of spike proteins. These spike proteins are the bumps that protrude from the surface of coronavirus particles. The body’s immune system then learns to spot these spike proteins and produces antibodies that block the virus from entering healthy cells in the future.
Studies show that vaccine recipients achieve immunity about two weeks after receiving the vaccine’s second dose. Scientists are still learning about how long that immunity will last.
The Pfizer vaccine is absolutely safe for children ages 12-15 years and teens ages 16 years and older. In clinical trials, enough teens and children participated to show that the vaccine is safe for 12-year-olds and older. We have no reason to expect that children would tolerate the vaccine less favorably than adults would.