The Nobel Prize in Physiology or Medicine has been awarded to scientists Katalin Kariko and Drew Weissman, who created the mRNA technology that was used to create Covid vaccines.
The technology was in experimental stages before the pandemic, but has now been used for millions of people around the world to protect them from Covid-19.
The same mRNA technology is being researched for other diseases, including cancer.
The Nobel Prize Committee said: "The laureates contributed to the development of vaccines during one of the greatest threats to human health in modern times."
Vaccines train the immune system to recognize and fight viruses or bacteria. During the Covid pandemic, Moderna and Pfizer/BioNTech vaccines were based on mRNA technology.
mRNA technology instructs cells in the body to produce specific proteins. mRNA essentially uses our body and biological processes to treat diseases and prevent infections.