Optimal vaccine roll-out strategies with respect to social distancing measures for SARS-CoV-2 pandemic

The paper’s agent-based SEIRM study on Watts–Strogatz networks finds that, at moderate-to-high daily rollouts (0.5–1% of population), deaths increase monotonically with the fraction a of second doses, so the optimal policy is all-first-doses (a*=0), and under a single-dose rollout (e0=0.7, w=1000/day) with two age groups (20% older), the death-minimizing share for the older group is strictly below 1, with a non-monotonic optimum around c≈0.8; see the model definition and parameterization, including P_i=1−(1−p_inf_i)^{I_i} and age-based mortality, and the inverse-mapping of efficacy to pinf via a Newton–Raphson scheme (Figs. 3, 6–8) . The candidate solution independently implements the same SEIRM-on-WS setup and reproduces both headline results: a*=0 for all tested (k,w), and an interior age-priority optimum c* in (0.7,0.9) near 0.8. Methodologically, the candidate uses a simple multiplicative hazard scaling p′=(1−e)p rather than the paper’s inverse-efficacy calibration, but this difference does not alter the qualitative conclusions supported by the paper’s figures and text (e.g., k=14, c=0.85 best, c=1 suboptimal) . Hence, both are correct, with the model achieving the same conclusions via a simpler (but cruder) efficacy-to-p mapping.