Nobel prize in medicine goes to scientists behind Covid-19 vaccine

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.

In recent decades, progress in the field of molecular biology has also enabled the development of vaccines based on individual viral components, rather than whole viruses.

In such vaccines, parts of the viral genetic code that code for proteins found on the virus surface, are used to make proteins that can stimulate the formation of virus-blocking antibodies in the body.

However, producing virus protein-based vaccines requires large-scale cell cultures and is a resource-intensive process limiting the possibilities for rapid vaccine production.

So scientists capitalised on a natural process in the body by which genetic information encoded in DNA is transferred to a molecule called the messenger RNA (mRNA), which is used as a template for protein production.

Dr Karikó developed methods over decades to use mRNA’s therapeutic potential.

Along with immunologist Drew Weissman, she focussed on how different RNA types interact with the immune system.

They looked at the immune system’s dendritic cells known to have important functions in the immune system’s surveillance process and in the activation of vaccine-induced responses in the body.

The duo produced different variants of mRNA each with unique chemical alterations and tested their effects on dendritic cells.

They found that inflammatory responses were almost abolished with small modifications to mRNA, leading to a paradigm change in how scientists understood the immune system.

These findings laid the path for increased protein production in the body using mRNA.

Their results were published in 2005, a decade and a half before the Covid-19 pandemic.

The vaccines, developed based on the findings of Dr Kariko and Dr Weissman, have saved “millions of lives and prevented severe disease in many more”, allowing societies to return to normal conditions, the assembly, which consists of 50 voting members composed of professors in medical subjects.

Their body of work over the years contributed to the unprecedented rate of vaccine development “during one of the greatest threats to human health in modern times”, the academy said.