There today, here tomorrow: A mother holds her child for a measles vaccination in Manila, Philippines, in January. Travelers are bringing measles from the Philippines to the United States.
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A child receives a polio vaccine Sunday in Kano, Nigeria. The country is the primary source of the virus in Africa but appears to be making progress against the disease; the current outbreak in Cameroon that has spread to Equatorial Guinea came by way of Chad, not Nigeria.