Figure 4From: Dynamic models of pneumococcal carriage and the impact of the Heptavalent Pneumococcal Conjugate Vaccine on invasive pneumococcal disease Model structure. Flow diagram illustrating the structure of the dynamic model used to assess pneumococcal vaccination. The following states are included: S, unvaccinated susceptible; Sv, susceptible vaccinated; V, unvaccinated carriers of pneumococcal serotypes contained in PCV7 or serotype 6A (vaccine serotype group, VT); Vv, vaccinated carriers of pneumococcal serotypes contained in PCV7 or serotype 6A; N, unvaccinated carriers of pneumococcal serotypes not contained in PCV7 (non-vaccine serotype group, NVT); Nv, vaccinated carriers of pneumococcal serotypes not contained in PCV7; i, age; t, time; λ, force of infection; γ, degree of protection against acquisition of VT carriage; ν, vaccine coverage; c, competition parameters; ω, waning rate of vaccine induced protection.Back to article page