Serotype-specific effectiveness against pneumococcal carriage and serotype replacement after ten-valent Pneumococcal Conjugate Vaccine (PCV10) introduction in Pakistan

• Type of Material: Article
• Authors: Muhammad Imran Nisar, Aga Khan University; Fyezah Jehan, Aga Khan University; Shahira Shahid, Aga Khan University; Sheraza Ahmed, Aga Khan University; Sadia Shakoor, Aga Khan University; Furqan Kabir, Aga Khan University; Aneeta Hotwani, Aga Khan University; Sahrish Muneer, Aga Khan University; Farah Khalid, Aga Khan University; Sajid Muhammad, Aga Khan University; Benjamin M Althouse, Bill & Melinda Gates Foundation; Hao Hu, Bill & Melinda Gates Foundation; Cynthia Whitney, Emory University; Asad Ali, Aga Khan University; Anita KM Zaidi, Aga Khan University; Saad Omer, Emory University; Najeeha Iqbal, Aga Khan University
• Language: English
• Date: 2022-01-21
• Publisher: PUBLIC LIBRARY SCIENCE
• Publication Version: Final Published Version
• Copyright Statement: © 2022 Nisar et al
• License: Creative Commons Attribution 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1371/journal.pone.0262466
• Title of Journal or Parent Work: PLOS ONE
• Volume: 17
• Issue: 1
• Start Page: e0262466
• End Page: e0262466
• Grant/Funding Information: This work was funded by the Bill and Melinda Gates Foundation Seattle, WA https://www.gatesfoundation.org/ to Muhammad Imran Nisar (grant ID OPP1111303). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
• Keywords: DISEASE; Science & Technology - Other Topics; NASOPHARYNGEAL CARRIAGE; CHILDREN; Science & Technology; STREPTOCOCCUS-PNEUMONIAE; Multidisciplinary Sciences
• Research Categories: Health Sciences, Pathology; Health Sciences, Public Health

Abstract

Objective Pakistan was one of the first South-Asian countries to introduce the ten-valent pneumococcal conjugate vaccine (PCV10) at the national level, using a 3+0 schedule without catchup, in 2013. Methods From 2014-18, fifteen children <2 years old were recruited every week in Matiari, Sindh, and nasopharyngeal swabs were collected. The samples were cultured, and pneumococcus was further serotyped through multiplex PCR at the Aga Khan University Hospital as per the method described by the Centers for Disease Control and Prevention, USA. Results Pneumococcus was detected in 2370/3140 (75%) children. Vaccine type (VT) and non-vaccine type (NVT) serotypes were carried by 379 and 1990 children. There was a significant decline in VT carriage (by 40.3%, p-value <0.001), whereas overall NVT carriage remained the same. The prevalence of VT serotypes 6B, 9V/9A, and 19F showed a significant decline by 58.8%, 79.3%, and 56%, respectively. The prevalence of NVT serotypes 19A, 21, and 10A increased by 70%, 33.3%, and 65.6%, respectively, whereas serotypes 13 and 9N/9L decreased by 53.4% and 51.8%, respectively. Serotype-specific vaccine effectiveness estimates that reached statistical significance were for 9V/9A (VE = 65.0, 95% CI 26.0-83.5%), 19F (VE = 55.3, 95% CI 15.5-76.4%) and for the vaccine related serotype 6A (VE = 28.4, 95% CI 0.9-48.2%). Conclusion The emergence of NVT serotypes, primarily 19A replacing VT serotypes in this rural community, necessitates continuous monitoring of serotypes in the carriage and invasive disease to evaluate the utility of existing vaccine formulations.