Yet the value of vaccines supplied through UNICEF is equal to less than 8 per cent of the world's expenditure on vaccines because UNICEF traditionally has purchased only vaccines that have been in the market for a substantial period of time and, thus, are less expensive.
然而，通过儿童基金会提供的疫苗价值还不足全球疫苗支出的8％，其原因是儿童基金会一向仅购买上市多年因此不太昂贵的疫苗。