In 1988 the World Health Assembly resolved to rid the world of poliomyelitis by the year 2000. It hasn’t happened, of course, but a lot has been achieved. The number of cases of poliomyelitis has fallen worldwide to less than 99% of the 1988 total, and endemic poliomyelitis (types 1 and 3 viruses) now occurs in only northern Nigeria, northern India, and at the Afghanistan–Pakistan border. Type 2 poliomyelitis disappeared in 1999. Monovalent oral poliovirus vaccines were …