In late 1940, before the U.S. entered World War II and just after earning his doctorate, Drew was recruited by John Scudder to help set up and administer an early prototype program for blood storage and preservation. He was to collect, test, and transport large quantities of blood plasma for distribution in the United Kingdom. Drew went to New York City as the medical director of the United States' Blood for Britain project. The Blood for Britain project was a project to aid British soldiers and civilians by giving U.S. blood to the United Kingdom.