Updated: Dec 16, 2020
Have you ever had a shot at the doctor's office before? The scientific name for a shot is a vaccine.
Even though it hurts to get a vaccine, they are very important because they keep you from getting sick from really bad diseases.
Vaccines work by teaching the immune system, which is your body's germ fighting system, to recognize and kill germs that could make you sick.
Vaccines have weak germs in them that make it easier for your immune system to kill the germs. Since cells in the immune system have a very good memory, the next time they see germs that looks like the one in the vaccine, they can get rid of them even faster.
Most of the time, this works very well. But sometimes, even the weak version of a germ can make people get sick.
There are vaccines for lots of different diseases. There are some vaccines, like for the flu, that you can get every year. But others, like for measles, mumps and rubella are given to you on a special schedule that your doctor follows.
Scientists have been working very hard to make a vaccine for SARS-CoV-2, the virus that causes COVID-19. Last week, two teams of scientists announced that they made vaccines that they think will work very well to keep people from getting the coronavirus.
But there is something very special about these new vaccines! For the first time ever, instead of putting a weak version of the virus into the vaccine, the scientists instead put in special particles called mRNA.
mRNA is short for messenger RNA. It works like a set of instructions, and one of the things that it does is control how the outside of a cell looks. When scientists put mRNA in a vaccine, it tells the body to make cells that look like the germ's cells, but that really aren't.
This is a big deal! When these fake germs are made by the body, the immune system still gets to practice getting rid of them. But since there is not a real germ in there, it is a lot safer for the person who gets