For the Record: A History of Yellow Fever Vaccine Requirements
Mark D. Gershman
The history of yellow fever vaccination requirements is best understood in the larger context of the history of international measures to prevent the spread of infectious diseases. The first international disease control measures were instituted in Europe in the 14th century in an attempt to prevent the spread of bubonic plague. Subsequently, cholera became the next major target of international disease control efforts. The lack of agreement between countries on the most effective means of disease prevention and lack of consistency in quarantine regulations eventually led to a series of International Sanitary Conferences.
The first International Sanitary Conference was held in Paris in 1851, and others were held periodically until 1944. Several international health organizations, including the Health Organization of the League of Nations, were established to oversee the various international regulations on disease control. The onset of World War II in 1939 severely disrupted the international public health functions of these organizations. The United Nations Relief and Rehabilitation Administration (UNRRA) was created by the Allies in 1943 to provide economic assistance to war-ravaged European nations, assist refugees, and conduct public health functions. (The UNRRA is unrelated to the more familiar United Nations organization, founded in 1945.) The public health responsibilities included the oversight of international quarantine activities, particularly those delineated in the updated International Sanitary Conventions of 1944, which contained yellow fever control measures. (The live attenuated 17D yellow fever vaccine had been developed and put into use by the late 1930s.) Specific provisions for national governments included quarantining a traveler from an endemic area who did not possess a valid vaccination certificate. This provision, which directed countries how to deal with unvaccinated travelers who may have been exposed to yellow fever virus, was the precursor to formal yellow fever vaccination requirements.
In order for the provisions of the Sanitary Conventions of 1944 to be carried out, areas where yellow fever was endemic had to be delineated. The conventions delegated this responsibility to the UNRRA, which appointed the Expert Commission on Quarantine. This commission created the first official map of yellow fever–endemic areas in 1945. Soon after the end of World War II, the responsibilities of the UNRRA were assumed by the newly formed World Health Organization (WHO), which appointed the Yellow Fever Panel. In 1949, the Yellow Fever Panel modified the original UNRRA map and issued its first report, which recommended that “measures may be applied permanently against arrivals from endemic areas.”
The International Sanitary Regulations (ISR), drafted by WHO to replace the previous International Sanitary Conventions, were adopted by the World Health Assembly in 1951. The ISR stipulated that “vaccination against yellow fever shall be required of any person leaving an infected local area on an international voyage and proceeding to a yellow fever receptive area.” Although only alluded to in previous International Sanitary Conventions, this was the first regulatory language that overtly mandated yellow fever vaccination requirements for country entry. The ISR were modified and renamed the International Health Regulations (IHR) in 1969; the IHR were completely revised in 2005, the most current iteration. The text regarding yellow fever vaccination requirements has been gradually modified. The IHR (2005) stipulate, “Vaccination against yellow fever may be required of any traveler leaving an area where the Organization has determined that a risk of yellow fever transmission is present.”
In 1960, WHO started to publish annually a listing of all the national yellow fever vaccination requirements in the booklet Vaccination Certificate Requirements for International Travel. This booklet gradually evolved into the WHO’s International Travel and Health. The book is no longer published, but the material remains online and lists country-specific yellow fever vaccination requirements, which are updated regularly. To keep its list current, WHO sends a questionnaire to all member countries yearly requesting any updates to their vaccination requirements. CDC publishes these same country requirements.