Table 1  Relative fitnesses of wild-type and escape epitopes before and after peak viremia
Peak viremiaWild-type epitopeEscape epitopea
Before11 – φ
After1(1 – φ)/(1 – c)
  • a φ is the cost of escape equivalent to the proportion of cells infected by virus carrying the escape mutation that die before viral reproduction, and c is the proportion of infected cells killed by a CD8+ T cell response targeting the epitope.