CRS is mainly caused by proinflammatory cytokines, including tumor necrosis factor (TNF)-α, interferon (IFN)-γ (produced by T cells), interleukin (IL)-1β and IL-6 (produced by myeloid cells) (8, 9), and CRS is more severe during the early stage of administration (4). This evidence concerns the gene IL6 and congenital rubella syndrome.