In 2015, Bangladesh introduced the ten-valent pneumococcal conjugate vaccine (PCV10). This study evaluates the impact of PCV10 on pneumococcal otitis media (OM), a prevalent middle ear infection amongst children in low-and-middle income countries, including Bangladesh. We analyzed ear swabs from OM cases with otorrhea collected at the largest pediatric hospital in Dhaka, Bangladesh from April 2014 to March 2019. The study involved identifying pathogens and conducting pneumococcal serotyping using the Quellung reaction. Four years post PCV10 introduction, the rate of detection of pneumococcus among otorrhea cases decreased from 18.4% (164/892) in 2014-15 to 15.6% (581/3735) in 2018-19, reflecting a 15.4% reduction. Notably, vaccine serotypes (VTs) demonstrated a significant decline throughout the post-PCV years, with a 44.1% reduction compared to the pre-PCV period. Specific VTs like 14, 6B and 19F exhibited significant reductions of 60.2% , 57.5% and 42.9%, respectively. Conversely, non-vaccine serotypes (NVTs) showed non-significant increase of 8.6%; 35B showed a 70.1% increase. Administration of two or three doses of PCV10 provided 84.4% protection against OM cases caused by serotypes covered by PCV10. This is the first report from South Asia assessing PCV's impact on pneumococcal OM. It demonstrates a 15.4% reduction in pneumococcal isolation over four years and over 80% efficacy of PCV10 in preventing vaccine type pneumococcal OM cases. While some vaccine serotypes decreased significantly, the impact of PCV10 on overall pneumococcal OM cases was dampened by increasing isolation of non-vaccine serotypes.

The authors have declared no competing interest.

This work was supported by Pfizer Inc (Grant number: WI209075). The funding organization had no role in the design, implementation, data analysis, manuscript writing or decision to publish this study.

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The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

This surveillance protocol was approved by the Institutional Review Board of Bangladesh Institute of Child Health at the Bangladesh Shishu Hospital and Institute, Dhaka, Bangladesh (formerly known as Dhaka Shishu Hospital).

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