TY - JOUR T1 - Predicting the impact of pneumococcal conjugate vaccine programme options in Vietnam: a dynamic transmission model JF - bioRxiv DO - 10.1101/121640 SP - 121640 AU - Olivier Le Polain De Waroux AU - W. John Edmunds AU - Kensuke Takahashi AU - Koya Ariyoshi AU - E. Kim Mulholland AU - David Goldblatt AU - Yoon Hong Choi AU - Duc-Anh Dang AU - Lay Myint Yoshida AU - Stefan Flasche Y1 - 2017/01/01 UR - http://biorxiv.org/content/early/2017/03/28/121640.abstract N2 - Background Catch-up campaigns (CCs) at the introduction of the pneumococcal conjugate vaccines (PCVs) may accelerate the impact of PCVs. However, limited vaccine supplies may delay vaccine introduction if additional doses are needed for such campaigns. We studied the relative impact of introducing PCV13 with and without catch-up campaign, and the implications of potential introduction delays.Methods We used a dynamic transmission model applied to the population of Nha Trang in Sout central Vietnam. Four strategies were considered: routine vaccination (RV) only, and RV alongside catch-up campaigns among <1y olds (CC1), <2y olds (CC2) and <5y olds (CC5). The model was parameterised with local data on human social contact rates, and was fitted to local carriage data. Post-PCV predictions were based on best estimates of parameters governing post-PCV dynamics, including serotype competition, vaccine efficacy and duration of protection.Results Our model predicts elimination of vaccine-type (VT) carriage across all age groups within 10 years of introduction in all scenarios with near-complete replacement by non-VT. Most of the benefit of CCs is predicted to occur within the first 3 years after introduction, with the highest impact in the first year, when IPD incidence is predicted to be 11% (95%CrI 9 – 14%) lower than RV with CC1, 25% (21 – 30 %) lower with CC2 and 38% (32 – 46%) lower with CC5.However, CCs would only prevent more cases of IPD insofar such campaigns do not delay introduction by more than 31 (95%CrI 30 – 32) weeks with CC1, 58 (53 – 63) weeks with CC2 and 89 (78 – 101) weeks for CC5.Conclusion CCs are predicted to offer a substantial additional reduction in pneumococcal disease burden over RV alone, if their implementation does not result in much introduction delay. Those findings are important to help guide vaccine introduction in countries that have not yet introduced PCV, particularly in Asia.CCCatch-up campaignCC1CC in <1 year oldsCC2CC in <2 year oldsCC5CC in <5 year oldsIPDInvasive Pneumococcal DiseaseMCMCMarkov Chain Monte-CarloNVTNon vaccine typePCVpneumococcal conjugate vaccinePCV7seven-valent PCVPCV1010-valent PCVPCV1313-valent PCVRVRoutine vaccinationvaccine efficacy against carriage conferring full protectionvaccine efficacy against carriage conferring partial protectionVTVaccine Type ER -