© UNICEF/HQ91-0902/Roger Lemoyne An infant in a Nigerian village is vaccinated. In 1990, the UN Convention on the Rights of the Child, including the right to health care, becomes international law. The same year, the world achieves an average 80 per cent immunization rate for all children under two against six major childhood diseases. It is a colossal achievement -- 10 years earlier, rates stood at 20 per cent -- that saves an estimated 2.5 million lives. The polio eradication effort draws on this experience.