UN campaigns for universal immunization against childhood diseases have eradicated smallpox and reduced cases of polio by 99 per cent, with the aim of eradicating it entirely by 2005.

• 联合国的儿童疾病全面免疫运动已消灭天花并使小儿麻痹症 病例数目减少99%25，目标是到2005年彻底消灭小儿麻痹症。