In 1916, During World War I, work by Hygienic Laboratory investigators changed the way smallpox vaccinations were administered to soldiers. They also found that shaving brushes were a source of anthrax and tetanus infections, and production methods were changed.

The Hygienic Laboratory focused on diseases which are caused by living germs or organisms which invade the body and produce the disease, and which were capable of being transmitted from one person to another, as in the cases of smallpox, scarlet fever, enteric, etc.