CD4 and infection: Nevertheless, the proportions of effector memory T-cells as a percentage of specific CD4+ T-cells were significantly higher (Figure 2C) (mean 79% ± 2 versus 58% ± 6), whereas proportions of specific effector CD4+ T-cells were significantly lower following vaccination compared with infection (Figure 2C) (mean 2% ± 1 versus 10% ± 3).