[Feature] The Truest Test
Over the past few years, there has been a surge in studies that intentionally infect volunteers with a wide variety of pathogens to test novel drugs and vaccines. The so-called "human challenge model" has a long and checkered past that began with 18th century experiments by smallpox vaccine developer Edward Jenner and later fell under intense scrutiny when they were conducted by Nazi doctors, military researchers, and academic scientists working with prisoners. Today, challenge experiments follow strict ethical guidelines, minimize risks to volunteers at every turn, and face increased scrutiny from regulatory agencies. The list of diseases being studied includes malaria, influenza, shigella, dengue, norovirus, tuberculosis, rhinovirus, Escherichia coli, typhoid, giardia, and campylobacter. And scientists who conduct human challenge studies, which typically involve a few dozen participants, say they have critical benefits: In addition to saving time and money, they can reveal harm caused by a potential drug or vaccine before it enters...