Runny Noses, Itchy Eyes

In 1906, Clemens von Pirquet, a Viennese pediatrician, noticed something peculiar when he treated children with diphtheria. Before the vaccine era, this disease was common and much dreaded, as the toxins produced by the diphtheria bacterium could cause fatal damage to the heart and airways. In Pirquet’s time, the standard treatment was equine antitoxin: antibodies from horse blood that neutralized the poison produced by diphtheria bacteria. Although children who received horse serum recovered, Pirquet found that many developed fever, rash and arthritis about 10 days later. This “serum sickness” heightened in severity, and came on more quickly, with repeated doses.