До ть будь ласка Disease is one of man’s greatest enemies. Between 1347 and 1351, about 25 million people in Europe (1)
by the Black Death. Before vaccines, people (2)
from disease. The first vaccine (3) in
about 1800, but the theory (4) for another 50 years. Today,
vaccines (5) to most children in developed world, but more vaccines
(6) in poorer countries.

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