Moderna and Pfizer vaccines use messenger RNA. How this science works

More than 600,000 doses of the Moderna vaccine will arrive today in California. The state started using the Pfizer vaccine this month. Both of these differ from any vaccine in the past to prevent the flu, measles or polio. These are RNA vaccines to fight COVID-19.

“With RNA vaccines, their sort of special, secret sauce is that they actually just contain the instructions to make a piece of the virus,” explains Paula Cannon, professor at USC’s Keck School of Medicine.

The RNA vaccine doesn’t inject a person with the virus. Instead, it takes a protein from the coronavirus to boost the body’s immune system.

“Your body becomes like a little mini pharmaceutical company and makes a little bit of the spike protein for you. Then your immune system sees that, recognizes it as foreign, and starts to make the immune responses and antibodies against the spike protein, that will then protect you in the future,” Cannon says.