Hungarian-American biochemist Katalin Karikó and American physician-scientist Drew Weissman have jointly been awarded the 2023 Nobel prize for physiology or medicine for their work leading to the development of mRNA Covid-19vaccines.

The Nobel Assembly at Karolinska Institutet said on Monday that the duo’s work on modifications to nucleoside molecules in life forms enabled the “development of effective mRNA vaccines against Covid-19.”

“Through their groundbreaking findings, which have fundamentally changed our understanding of how mRNA interacts with our immune system, the laureates contributed to the unprecedented rate of vaccine development during one of the greatest threats to human health in modern times,” the Nobel Assembly noted in a statement.

Vaccines work by stimulating the formation of an immune response to a particular pathogen giving the body a head start to fight the disease-causing microbe in the event of a later exposure.

Widely used vaccines until the Covid-19 pandemic were based on killed or weakened microbes such as viruses, including examples like polio, measles, and yellow fever shots.