Despite this, there were no significant differences between the frequency of T-cells that co-produced IFNγ and IL-2 measured at three months after vaccination with that at three, six, and twelve months after infection (mean SI 4.8 ± 0.7, 5.6 ± 0.9, 5.8 ± 1.2 and 5.8 ± 0.7, respectively). The gene discussed is IFNG; the disease is infection.