The vaccine made it easier to halt new transmissions and protect healthy people, even if responders arrived at a smallpox outbreak that was already underway.
This means the type of disease tracking that officials used to detect smallpox epidemics is impossible for polio.
But Guinea worm eradication has grown more complex over the past five years as doctors have recognized that it’s not a human-specific infection, as had been assumed: Recent studies have demonstrated that dogs, frogs and fish can also transmit the pathogen.
As a result, worldwide measles deaths have already dropped by approximately 20% since 2000, and the disease has been eliminated in the U.S., meaning it’s no longer constantly present here (despite occasional cases brought in by travelers).
But while it’s a good candidate for eradication based solely on its biology, measles doesn’t share smallpox’s crucial psychological factor: People don’t fear it enough.