 The study found that catch-up campaigns may accelerate the impact of pneumococcal conjugate vaccines, PCVs, but supply constraints could limit their benefit if additional doses delay introduction. The dynamic transmission model showed that routine vaccination only would eliminate vaccine-type serotypes in carriage across all age groups within 10 years after introduction, with near-complete replacement by non-VT. Most of the benefit of CCS is predicted to occur within the first three years, with the highest impact at one year when IPD incidence is predicted to be lower with CC1, CC2, and CC5. However, CCS would only prevent more cases of IPD if they do not delay introduction by more than about 6, 12, and 18 months for CC1, CC2, and CC5. This article was authored by Olivier LaPaulaine de Warrou, W. John Edmonds, Pensuk Tokahoshi, and others.