But paying for and delivering these vaccines to the most vulnerable citizens of low-income countries poses a significant challenge. Although the World Health Organization (WHO) has recommended including the hepB vaccine in routine immunization since 1992, its high price initially hindered its uptake in some developing countries.
但购买并将这些疫苗送到最脆弱的低收入国家公民手中仍是一项重大挑战。尽管世界卫生组织在1992年便已建议将乙肝疫苗纳入常规免疫，但其高昂的价格仍限制了其在一些发展中国家的使用。后来，同样的问题又出现在推广HPV疫苗上。但全球疫苗免疫联盟（GAVI Alliance）的出手干预保证了乙肝不再是个问题，HPV亦然。