Smallpox produced the death of up to thirty percent of those infected, so Jenner's preventive method spread quickly. The Spanish government designed and supported a ten-year effort to carry smallpox vaccine to its American and Asian territories in a chain of arm-to-arm vaccination of children. An expedition directed by Doctor Francisco Xavier de Balmis sailed from Corunna in November 1803, stopping in the Canary Islands, Puerto Rico, and Venezuela. Balmis led a subexpedition to Cuba, Mexico, and the Philippines; his assistants returned to Mexico in 1807, while Balmis took vaccine to China and returned to Spain (and again to Mexico, 1810-13). Vice-director José Salvany and his staff took vaccine to present-day Colombia, Ecuador, Peru, Bolivia, and Chilean Patagonia. The Spanish Royal Philanthropic Vaccine Expedition shows the first attempts to solve questions still important for the introduction of new immunizations--professionalization in public health, technology transfer, protection of research subjects, and evaluation of vaccine efficacy, safety, and cost.