Serum Therapy Day (Kessei Ryōhō no Hi)

What Is Serum Therapy Day?

December 4 is "Serum Therapy Day." It commemorates December 4, 1890, when German bacteriologist Emil von Behring and Japanese bacteriologist Shibasaburo Kitasato published their research on "serum therapy" for diphtheria and tetanus. This discovery transformed the history of infectious disease treatment, and Behring went on to receive the very first Nobel Prize in Physiology or Medicine in 1901.

Who Was Shibasaburo Kitasato?

Shibasaburo Kitasato (1853–1931), often called "the father of modern Japanese medicine," was a bacteriologist from Kumamoto. Studying under Robert Koch, he achieved the world's first pure culture of the tetanus bacillus and discovered its toxin, and co-developed serum therapy with Behring. He's also known for discovering the plague bacillus, and he founded the Kitasato Institute and helped establish the Keio University School of Medicine, serving as its first dean (Kitasato University was later founded by the Kitasato Institute). His portrait was featured on the new 1,000-yen note issued in 2024.

The Difference Between Serum Therapy and Vaccines

• Serum therapy (passive immunity): Administering a serum containing antibodies to provide immediate immunity. Effective for patients who have already developed symptoms
• Vaccines (active immunity): A preventive method that involves injecting a weakened or inactivated pathogen so the body builds its own immunity

The idea behind serum therapy — using antibodies as treatment — lives on in modern antibody drugs (monoclonal antibodies), which are used to treat cancer, autoimmune diseases, and more.