Literature update ViVa week 30-2026

1. Two months earlier beats twice as fast: modeling shows South Korea’s vaccine timing, not speed, saved the most lives Summary: This scenario-based modeling study used an age-structured compartmental model calibrated to South Korean surveillance data (November 2020–December 2021) to evaluate counterfactual COVID-19 policies across pre-Delta and Delta periods, incorporating vaccination, testing capacity, contact tracing (Q-proportion), and social distancing. Introducing vaccination two months earlier reduced cumulative confirmed cases by 48%, outperforming a fourfold faster rollout. Reducing testing capacity to 90% increased Delta-period cases 4.7-fold; a modest 10% contact-tracing improvement cut cases by up to 74%. Delaying pandemic-recovery relaxation by two months mitigated Delta resurgence. The authors concluded that deployment timing and sustained detection capacity outweighed intervention intensity alone. Comment: Yes—the earlier vaccination starts, the more cases are prevented. Simple enough. However, other parameters contribute just as significantly to case numbers and death tolls. This study challenges the “rollout speed” fixation dominating vaccine planning discourse:...