Fig 8. Illustration of adaptive treatment above the immunity threshold (Ω > k).

A) Clearance dynamics when Ω is sufficiently high (Ω = 10k), i.e. satisfies Eq 22. B) No clearance dynamics, when Ω is too close to k (Ω = 5.6k), and adaptive treatment induces oscillatory dynamics. C) High rate of effector cell conversion into memory f = 0.1. D) Lower rate of conversion into memory f = 0.05. When persistent immunity accumulates faster, the range of symptom thresholds where adaptive treatment works, approaches the host immunity threshold, enabling treatment success at lower pathogen densities. Parameters as in Table 1, with k = 10⁵.