COPENHAGEN, Denmark – Professor Jean-Laurent Casanova is the recipient of the prestigious 2025 Novo Nordisk prize, a recognition of his transformative research in understanding infectious diseases. Casanova’s decades-long work has shifted the scientific perspective from solely blaming viruses and bacteria for infections to recognizing the critical role of genetics. His discoveries have identified over 70 genes that, when mutated, can significantly compromise an individual’s ability to fight off specific infections. This groundbreaking research has profound implications for personalized medicine and public health.

Casanova’s research has revealed that both rare and relatively common genetic mutations can make individuals exceptionally vulnerable to infections that most people overcome without difficulty. This paradigm shift is revolutionizing the diagnosis,treatment,and prevention of infectious diseases,paving the way for tailored medical approaches based on individual genetic profiles.

Casanova explains the driving force behind his research: Why would ‌a child be⁤ hospitalised for viral pneumonia, tuberculosis or any other severe infection when most children‌ infected with‍ the very same microbe do well? That ‍is what⁣ I call​ the infection enigma.

His work has not only deepened the understanding of human immunity but has also paved the way for personalized medicine, enabling clinicians to better predict, diagnose, and treat infectious diseases based on individual genetic profiles. This approach promises more effective treatments and preventive strategies tailored to a person’s unique genetic makeup.

Recognizing a Landmark Scientific Contribution

Mads Krogsgaard Thomsen, CEO of the Novo nordisk Foundation, emphasized the meaning of Casanova’s contributions, stating, His work exemplifies the power of integrating clinical observation with genetic research. By uncovering the genetic basis of susceptibility to infections, Professor Casanova has opened new avenues for personalised medicine, offering hope for more effective treatments and preventive strategies.

Professor Jørgen Frøkiær, Chair of the Novo nordisk Prize Committee, added, Jean-Laurent Casanova’s research has transformed understanding of infectious diseases by revealing the critical role of genetic factors. His discoveries have provided new insight into why some individuals are more vulnerable to infections, paving the way for novel approaches in immunology and public health.

For Casanova, the recognition is both a surprise and a validation of his career-long dedication to reshaping the understanding of infections. When I got the call, I had no idea I had even been nominated, he said. But this is by far the most crucial award I have received in my career, and I am incredibly honoured.

Beyond the Virus: The Role of Individual Immunity

Casanova’s journey began in Paris, where he pursued simultaneous studies in medicine and biology, creating his own MD and PhD program before such dual-degree tracks were common in France. His decision to specialize in pediatrics and immunology shaped the trajectory of his research.

As a young paediatrician, I saw children die from infections in intensive care units, he recalled. That made me realise that infection was the biggest problem in paediatrics. I wanted to understand why some children got severely ill while others did not.

At the age of 30, he embarked on a quest to unravel the “infection enigma,” establishing his laboratory in Paris before expanding to New York. over the years, his team has demonstrated that genetic errors in immunity explain why certain individuals suffer from severe infectious diseases. This insight has proven invaluable during global health crises, including the COVID-19 pandemic.

one of Casanova’s most meaningful breakthroughs occurred during the COVID-19 pandemic when his team discovered that some individuals possessed “bad” antibodies, known as autoantibodies, that attacked their own immune system rather than the virus. These autoantibodies block type I interferons, which are essential for fighting infections. His research revealed that these faulty antibodies were responsible for approximately 15% of severe COVID-19 cases and 20% of deaths.

This was clear proof that a person’s genes and immune system play a big role in how sick thay get from infections, he explained. It is indeed not just about the virus — it is also about how your body responds to it.

Challenging Conventional Wisdom

These harmful autoantibodies are not limited to COVID-19. Casanova’s team has identified them in other severe viral infections, such as influenza and West Nile virus, where they account for nearly 40% of the most severe cases.

If you have these autoantibodies, you have to be extra careful about infections and insect bites that spread viruses, Casanova warned. Testing older adults for these antibodies could also help to save lives in countries that can afford it.

Casanova’s team initially discovered that rare genetic mutations prevented some individuals from producing type I interferons. Subsequently, they found that autoantibodies could achieve the same affect, blocking immune defenses and increasing the risk of severe infection. This finding helped explain why some individuals become critically ill while others recover quickly.

These individuals can be identified through genetic testing or by screening for autoantibodies in their blood. Once diagnosed, some patients may benefit from treatments, such as interferon therapy to replace the missing immune signal or therapies to remove the harmful autoantibodies, helping to restore their body’s ability to fight infections.

For a long time, the scientific community primarily focused on germs – bacteria and viruses – as the primary cause of illness. However, Casanova’s discoveries challenged this conventional wisdom, highlighting the crucial role of individual genetic predispositions in determining susceptibility to severe infections. his work continues to shape the future of infectious disease research and treatment.

Revolutionizing the Understanding of Human Immunity

for decades, the prevailing view in infectious disease research centered primarily on the pathogens themselves—the viruses, bacteria, and fungi that cause illness. Though,Jean-Laurent Casanova’s research has challenged this long-held belief,demonstrating that individual genetic differences play a crucial role in determining susceptibility and resistance to infections. his work has revealed that variations in our genes can significantly impact how our immune systems respond to these pathogens, influencing the severity and outcome of infections.

Casanova’s journey began with a keen observation of the “infection enigma”—the perplexing phenomenon where individuals exposed to the same pathogen exhibit vastly different responses. Some develop severe, life-threatening illnesses, while others experiance only mild symptoms or remain entirely asymptomatic. This disparity sparked his decades-long inquiry into the genetic factors that govern our immune defenses.

Through meticulous research, Casanova and his team have identified over 70 genes whose mutations can render individuals highly vulnerable to specific infections.These genetic defects can impair various aspects of the immune system, from the production of critical immune cells to the signaling pathways that coordinate the body’s defense mechanisms.This discovery has profound implications for how we understand, prevent, and treat infectious diseases.

“For more than a century, we have been taught to focus almost entirely on microbes,”
Jean-Laurent Casanova

Casanova emphasizes the long-overlooked role of genetics in immunity, stating:

“but genetics has always played a role — this was proven for plants over 100 years ago and for humans before World War II. we just did not fully appreciate it.”
Jean-Laurent Casanova

Paving the Way for Personalized Medicine

Casanova’s research has opened up exciting new avenues for personalized medicine in the fight against infectious diseases. By identifying the specific genetic vulnerabilities that predispose individuals to severe infections,clinicians can tailor diagnostic,preventative,and therapeutic strategies to each patient’s unique needs.

For example, individuals with known genetic defects affecting their immune response could benefit from targeted vaccination programs or prophylactic treatments to bolster their defenses.Similarly, patients suffering from severe infections could undergo genetic testing to identify underlying immune deficiencies, allowing for more precise and effective treatment interventions.

Casanova’s work extends beyond simply understanding infections; it aims to rewrite the medical playbook for preventing and treating them. He explains:

“By studying rare patients with rare genetic vulnerabilities, we uncovered something that affects millions. This is just the beginning.”
Jean-Laurent Casanova

Looking Ahead: A Future Shaped by Genetic Insight

As the field of infectious disease research continues to evolve, casanova’s discoveries provide a clear roadmap for future advancements. The ability to identify genetic vulnerabilities before illness strikes offers unprecedented opportunities for personalized interventions, such as tailored vaccination programs and lifestyle adjustments.

The 2025 Novo Nordisk Prize recognizes Casanova’s significant contributions to the pursuit of a more personalized and effective approach to infectious disease medicine, placing his work at the forefront of this transformative field.

The Novo Nordisk Prize award ceremony will take place on April 25, 2025, in Bagsværd, Denmark. Prior to the ceremony, on April 24, 2025, Casanova will deliver a Prize Lecture at the Panum Institute, University of Copenhagen, in the Niels K.Jerne Auditorium, Building 13.

About Jean-Laurent Casanova

• 1987 MD, University of Paris Descartes, France
• 1992 PhD in Immunology, University of Paris Pierre and Marie Curie, France
• 1999 Professor of Paediatrics, Necker Medical School, Paris, France
• 1999 Co-founder, Laboratory of Human Genetics of Infectious Diseases, Institut imagine, Inserm, AP-HP, Université Paris Cité, Paris, France
• 2008 Professor, The Rockefeller University, New york, USA
• 2014 Investigator, Howard Hughes Medical Institute, The Rockefeller University, New York, USA
• 2015 Foreign Member, United States National Academy of Sciences
• 2015 Foreign Member, United States National Academy of Medicine

About the Novo Nordisk Prize

The Novo nordisk Prize recognizes active scientists who have made outstanding international contributions to advance medical science to benefit people’s lives. The prize is awarded annually by the Novo Nordisk Foundation and is intended to further support biomedical research in Europe.

The prize is accompanied by DKK 5 million (€672,000) and comprises a DKK 4.5 million (€605,000) research grant and a personal award of DKK 0.5 million (€67,000). The Foundation will also award an additional DKK 0.5 million for hosting an international symposium within the recipient’s field(s) of research.