Wasn't polio wiped out? Why it is still a problem in some countries

FILE - A health worker administers a polio vaccine to a child in Karachi, Pakistan, Jan. 8, 2024.

Polio was eliminated from most parts of the world as part of a decadeslong effort by the World Health Organization and partners to wipe out the disease. But polio is one of the world's most infectious diseases and is still spreading in a small number of countries. The WHO and its partners want to eradicate polio in the next few years.