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AIzaSyAYiBZKx7MnpbEhh9jyipgxe19OcubqV5w
October 1, 2025
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polio
Category:
Otro
Actualizado:
26 nov 2017
1
0
456
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Sophie
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eee
By
Sophie
26 nov 2017
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0
488
Eventos
Polio was the most feared disease of this time.
Jonas Salk announced that he was developing a trial vaccine for polio.
The Salk vaccine was tested on 1.8 million schoolchildren.
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