Between the Fall of 1942 and Spring of 1944, an epidemic of pneumococcal pneumonia struck 1,500 among the almost 10,000 trainees at an Army Air Force Technical School in Sioux Falls, South Dakota. In collaboration with military physicians, Heidelberger devised a field trial to test whether injections of half the soldiers in the camp with a combination of purified polysaccharides of the four specific pneumococcal types most prevalent among the soldiers--types I, II, V, and VII--would impart immunity against these types. Heidelberger prepared the purified polysaccharide antigens with the help of the pharmaceutical company E. R. Squibb. Colin MacLeod (who, also in 1944, along with Oswald Avery and Maclyn McCarty discovered that genes were made of DNA) organized the trial, which was overseen on site by military physicians Richard Hodges and William Bernhard. In this article, the four leaders of the study presented their successful findings: incidences of pneumonia caused by the four pneumococcal types whose polysaccharide antigens were injected fell to near zero among the inoculated population within two weeks, while pneumonias caused by two other types (IV and XII) remained prevalent, as did all forms of pneumonia among soldiers who had not received inoculations. The overall incidence of pneumonia, however, was much reduced because inoculation of every other soldier impeded transmission of the disease.
Copyright:
This item may be under copyright protection; contact the copyright owner for permission before re-use.