To see the impact of PCV-10 on meningitis, pneumonia and sepsis by using “before-after” and case-control study using “indirect cohort”. This study will be done in a network of 4 sentinel sites, using the baseline data of 2007 to 2014.
Bill & Melinda Gates Foundation
Pneumococcal infections are a leading cause of serious illness, disability, and death worldwide. Despite substantial evidence of disease burden and a WHO position paper advocating for routine immunization with Pneumococcal Conjugate Vaccine (PCV), its introduction remains slow in South Asia. This is mainly due to a lack of evidence on disease burden and vaccine benefits that would convince policy makers to takedecisions. Our group has a track record for successfully performing such evaluation, substantial pre-introduction disease burden data, and well-established sentinel and field sites that offer an unique opportunity to conduct an assessment of PCV benefits in a low-income setting in Asia. We therefore propose to leverage the ongoing surveillance at the sentinel sites and the nested field site to evaluate the impact of PCV on Invasive Pneumococcal Diseases (IPD) through two objectives:
1) To quantify the effects of PCV10 introduction on the number of hospitalizations caused by Vaccine type IPD (VT-IPD) in children 2) To assess the effectiveness of PCV10 against VT-IPD using an indirect cohort analysis of all culture positive/negative IPD cases with known serotype.
The study will take place in Dhaka, with cases being identified at the two largest children’s hospitals– Dhaka Shishu Hospital (DSH) and ShishuShasthya Foundation (SSF). Data collection for the two objectives will be similar. Surveillance methods and systems already in placewill remain largely unchanged to allow for comparisons of disease rates and case numbers before and aftervaccineintroduction.In addition, for the indirect cohort analysis, we will add cases identified through real-time PCR and real-time PCR serotyping, a new technique that will add to the already strong program of diagnostics conducted in the Dhaka Shishu Microbiology laboratory.
Cases of IPD will be defined as lab-confirmed pneumococcus identified from normallysterile body fluid from a child
For the before-after study (Objectives 1), the number (or rate) of VT-IPD cases in the post-vaccine period (2015-2017) will be compared to VT-IPD cases from baseline years (2007-2013). Only those cases identified using clinical and lab methods in place before vaccine introduction will be eligible for inclusion in this analysis. For the indirect cohort analysis, all cases with known serotype identified after vaccine introduction will be eligible for the analysis, with vaccine effectiveness calculated by comparing the odds of vaccination among children with VT-IPD to that among children with non-vaccine type IPD (NVT-IPD). We plan to communicate interim reports on study progress to partners yearly and anticipate that data collection and final analyses will be completed by June 2018, with final reports available at that time.
This project has long-term implications for sustaining and strengthening the ability to monitor pneumococcal disease in Bangladesh. This study will continue to build both laboratory and epidemiological capacity to continue surveillance for IPD after PCV10 is incorporated into the routine immunization program. The addition of real-time PCR for detection of pneumococcal infections and serotyping will add strength to an already highly capable laboratory. Methods adopted to obtain accurate vaccination histories and conduct analyses of vaccine impact will strengthen the epidemiological capacity in Bangladesh. Furthermore, the ongoing surveillance continued by the study will allow us to assess changes in serotype distribution over time and monitor any increases in NVT serotypes.