Soper's wartime responsibilities in the Mediterranean ended in May 1946. He planned to spend the summer in the U.S., catching up on public health developments and institutions, before returning to Egypt to establish a regional office in Cairo for the Rockefeller Foundation. Meanwhile, plans were underway for a new international health organization that would be associated with, but politically independent of the United Nations (i.e., having its own treaty, constitution, membership, and budget). The planners hoped that this World Health Organization (WHO) would make several older international health organizations redundant, and absorb or dissolve them. One of these was the Pan American Sanitary Bureau (PASB).
Established in 1902 as the International Sanitary Bureau, PASB was a regional organization serving the 21 republics of the Americas. Initially, it was responsible for calling the Pan American Sanitary Conferences, where member countries could exchange information about the incidence of communicable diseases, especially those subject to quarantine, and for aiding countries requesting assistance in the solution of public health problems, particularly in port cities. In 1924 the Pan American Sanitary Code, the first Pan American treaty to be ratified by all 21 of the Member States of the Pan American Union, set up the Bureau (renamed the Pan American Sanitary Bureau in 1923) as an independent organization governed by the Pan American Sanitary Conferences. This sanitary treaty assigned the Bureau broader functions and responsibilities as the central coordinating agency for international health activities in the Americas. In the WHO negotiations during 1946, PASB had campaigned to retain its identity, and to serve as the Regional Office of the World Health Organization for the Americas. The matter could not be settled until the first World Health Assembly convened, and that, in turn, depended on the ratification of the WHO constitution by 26 of the 33 signatories. The process would take nearly two years.
Meanwhile, PASB Director Hugh Cummings and U.S. Surgeon General Thomas Parran approached Soper about becoming the next Director. Soper found the prospect attractive, but worried about whether PASB could find sufficient operating funds. In December 1946, Soper became the official candidate of the U.S. Government for the PASB directorship. He was elected at the 12th Pan American Sanitary Conference in January 1947, and started his first four-year term in February. At the conference, delegates also created an umbrella organization, the Pan American Sanitary Organization (PASO), composed of the PASC, a Directing Council, an Executive Committee, and PASB. PASB was to serve as the executive agency of PASO. A new constitution was approved, which opened membership to all American nations and territories, and broadened the field of operations to the entire Western Hemisphere. It also enabled PASO to negotiate with WHO even before WHO's charter became operative in 1948.
It was clear to Soper that to be effective at this expanded size (whether as part of WHO or on its own) PASO would need to increase its funding base. PASO drew all of its support from its member nations. Of this, the U.S. paid about 52%, and paid the salaries of almost all PASB's professional technical staff (who were assigned from the U.S. Public Health Service). During World War II the U.S. had given PASB additional funding of about $500,000 for special programs and fellowships. By 1946, the USPHS wanted to pull out its professional staff and cut back fellowship programs. One of Soper's first steps as Director was to find out whether WHO would pick up the budgetary shortfalls caused by these changes. WHO could not, and neither could the United Nations.
Soper suggested to the PASO Executive Committee that he be authorized to request and receive special voluntary contributions from member countries. Then, beginning with Brazil, Soper visited the leaders of these nations, explained the situation, and got voluntary one-time pledges totaling $1,000,000, plus increased annual contributions. PASO's budget resources for 1947 had been less than $100,000; for 1948, they were $1,300,000.
This allowed PASO to enlarge its program independently of WHO, and "made it impossible for WHO to insist on absorbing PASB; the Bureau had simply become too big to be absorbed by the very new and still to be tested WHO." By the time the first World Health Assembly met in 1948, PASB had a budget and a program that could not be integrated into the relatively small budget voted for WHO. So PASO retained its identity, and PASB became WHO's Regional Office for the Americas. Partly at Soper's urging, the World Health Assembly also defined five other WHO regions and set up regional offices.
Fred Soper served two more four-year terms as Director of PASB, and retired in early 1959. During this time, he drew on his 27 years of public health experience to manage a broad spectrum of public health work in Mexico, the Caribbean, Central America, and South America, coordinating PASO's work with that of WHO, UNICEF, state and local public health departments, and other agencies.
Besides standard public health work--sanitation, vaccination, diagnosis and treatment, maternal and child health, and health education--PASO supported epidemiological surveys, laboratory investigations, and training programs for physicians, nurses, veterinarians, medical scientists, lab and radiology technicians, entomologists, and other personnel.
Upon his retirement, Soper was appointed Director Emeritus and continued his association with PASO (renamed the Pan American Health Organization (PAHO) in 1958).