Stephen Arnon

Stephen Arnon (October 14, 1946 – August 17, 2022) was an American physician, and infant botulism researcher. He is credited with the first descriptions of infant botulism and led the development of a successful orphan drug program to treat infant botulism, BabyBIG. Uniquely the drug was developed and initially manufactured by the public sector. BabyBIG was subsequently approved by the FDA in 2003 and is the major treatment for infant botulism. The treatment can significantly shorten hospitalization. Stephen Arnon trained in medicine at Harvard Medical School and spent his career working for the California Department of Health, where he established and led the Infant Botulism treatment and prevention program.

Discovery of infant botulism Infant botulism is a unique form of the disease botulism distinguished from most cases of adult botulism by its etiology. Instead of intoxication by foods containing botulinum neurotoxin complexes, the disease is characterized by colonization and subsequent toxin production within the gastrointestinal tract. In a pivotal paper in 1976, Arnon and Thaddeus Madura described their isolation of Clostridium botulinum bacteria from infants in California suffering from the symptoms of botulism, including flaccid paralysis.

Work by Arnon and colleagues would continue where he and colleagues were the first to describe the association of infant botulism with honey.

Development of BabyBIG Since infant botulism is the result of colonization with Clostridium botulinum bacteria, result antitoxins can reduce the length of the disease. The disease is caused almost exclusively by Botulinum neurotoxins serotypes A and B. The heptavalent botulinum antitoxin (targeting all seven major serotypes) was considered by Clinicians to be inappropriate for infants infected with Clostridium botulinum. As a result Arnon's team worked to develop BabyBIG, an orphan drug which is an human polyclonal antiserum to be given to infants with botulism. The drug is near unique in the United States in that it was developed as a public service by a state public health authority and manufactured by another state health authority, the Massachusetts Public Health Biologic Laboratories who manufactured the first batch of the drug without charge.

In 2006, a pivotal clinical trial published in the New England Journal of Medicine showed that BabyBIG significantly reduced length of hospital stay, and patient ICU costs. For instance in November 2025, an active outbreak was detected by Infant Botulism Treatment and Prevention Clinicians leading to recall of contaminated baby formula.

Personal life Stephen Arnon was the son of Daniel Israel Arnon, a noted professor of plant biology at University of California, Berkeley.

Honors Fellow of the Infectious Disease Society of America

Distinguished Commendation by the Commissioner of the Food and Drug's Administration.