1580BC1796190919161921193819501952
 
 
c.UNICEF/ICEF0895
UNICEF/ICEF0895

A boy is tested for tuberculosis in a rural part of the Philippines in the 1950s. In 1952, UNICEF develops a 'cold chain' supply system to keep vaccines cold — and potent --from manufacturer to recipient. Experience in several African and Asian countries had shown that exposing vaccine to high temperatures could make them ineffective.