Small pox did kill many native Americans and Spaniards. It was one of the major diseases that decimated the native population of the Americas following European contact. Smallpox was brought to the Americas by European colonists and quickly spread among the indigenous population, who had no immunity to the disease. It is estimated that smallpox killed up to 90% of the Native American population in some areas. Smallpox also killed many Spaniards, but to a lesser extent than Native Americans. The Spanish had some immunity to the disease, as it had been present in Europe for centuries. However, the disease still caused significant mortality among the Spanish population in the Americas.