Scott B Halstead

Early life and education Scott Halstead was born in 1930 in Lucknow, India to Gordon P. and Helen Halstead, Methodist missionaries based in Lucknow. In 1936, they moved to White Plains, NY, where he attended White Plains High School.

He graduated from Yale University with a BA in sociology in 1951 and from Columbia University with an MD in 1955.

Career Early research In 1957, Halstead was drafted by the U.S. Army Medical Corps.

In 1965 Halstead left Bangkok to join the Yale Arbovirus Research Unit, part of the Yale School of Public Health. In a memoir published in 2002, he wrote that he worked at the newly opened Department of Epidemiology and Public Health, where he also worked on his dengue data set at Yale and published white papers that consolidated his research.

In 1967 he presented the first paper describing severe dengue hemorrhagic fever as the result of a second infection by one of the other four types of dengue, a phenomenon now known as antibody-dependent enhancement (ADE).

During this period he helped found International Clinical Epidemiology Network (INCLEN), a global research and medical-education network designed to strengthen the research capacity of medical schools in the developing world.

In 1990, while with the Rockefeller Foundation, Halstead co-founded the Children's Vaccine Initiative, now the Global Alliance for Vaccines and Immunization (GAVI). He served as director of research and development from 2003 to 2010.

Dengvaxia controversy Halstead played an important role during 2015–19 as a consultant and later as a scientific critic of Sanofi Pasteur’s Dengvaxia, the first dengue vaccine to be licensed for widespread use in countries where dengue is prevalent. Sanofi rebutted their analysis and sold Dengvaxia to the Philippines, where 700,000 school age children were vaccinated. An alarming rate of hospitalizations were found in vaccinated children following a dengue exposure.

After an analysis of Phase 3 clinical trial data, Sanofi scientists concluded that Halstead and Russell were correct and that Dengvaxia posed a significant risk for previously uninfected people. More cases were likely after vaccination due to a subsequent dengue infection.

That led to the vaccine being banned in the Philippines, and Sanofi and Filipino public health officials were accused of malfeasance in proceeding with an unproven vaccination program. In 2018, Halstead served as an expert witness, testifying in person at Philippines Senate hearings on what became known as the Dengvaxia controversy.

COVID-19 During the global COVID-19 pandemic that started in 2019, Halstead began researching protecting at-risk groups via antibody-based strategies including convalescent plasma and monoclonal antibodies. He published papers about vaccine development and potential risks associated with ADE including vaccine hypersensitivity reactions, to assist with ongoing COVID-19 prevention.

Awards and recognition In 2017, Halstead received the Walter Reed Medal from ASTMH.