In addition to its use in the U.S., Dryvax was used in a major phase of the successful program to eliminate smallpox carried out in West and Central Africa and in other parts of the global program (Federal Register 45:25683-25688, 1980). As demonstrated during this global campaign, a vaccine "take," as evidenced by the presence of a scar resulting from previous smallpox vaccination, was associated with protection against disease. More detail on what constitutes a take is found in the following section. | 
