High residual carriage of vaccine-serotype Streptococcus pneumoniae after introduction of pneumococcal conjugate vaccine in Malawi

Nat Commun. 2020 May 6;11(1):2222. doi: 10.1038/s41467-020-15786-9.

Abstract

There are concerns that pneumococcal conjugate vaccines (PCVs) in sub-Saharan Africa sub-optimally interrupt Streptococcus pneumoniae vaccine-serotype (VT) carriage and transmission. Here we assess PCV carriage using rolling, prospective nasopharyngeal carriage surveys between 2015 and 2018, 3.6-7.1 years after Malawi's 2011 PCV13 introduction. Carriage decay rate is analysed using non-linear regression. Despite evidence of reduction in VT carriage over the study period, there is high persistent residual carriage. This includes among PCV-vaccinated children 3-5-year-old (16.1% relative reduction from 19.9% to 16.7%); PCV-unvaccinated children 6-8-year-old (40.5% reduction from 26.4% to 15.7%); HIV-infected adults 18-40-years-old on antiretroviral therapy (41.4% reduction from 15.2% to 8.9%). VT carriage prevalence half-life is similar among PCV-vaccinated and PCV-unvaccinated children (3.26 and 3.34 years, respectively). Compared with high-income settings, there is high residual VT carriage 3.6-7.1 years after PCV introduction. Rigorous evaluation of strategies to augment vaccine-induced control of carriage, including alternative schedules and catch-up campaigns, is required.

Publication types

  • Observational Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Child
  • Child, Preschool
  • Cross-Sectional Studies
  • Demography
  • Female
  • HIV Infections
  • Humans
  • Infant
  • Malawi
  • Male
  • Nasopharynx / immunology
  • Pneumococcal Vaccines* / administration & dosage
  • Prevalence
  • Prospective Studies
  • Serogroup
  • Streptococcus pneumoniae / immunology*
  • Streptococcus pneumoniae / isolation & purification
  • Time Factors
  • Vaccination
  • Vaccines, Conjugate / administration & dosage
  • Vaccines, Conjugate / adverse effects

Substances

  • Pneumococcal Vaccines
  • Vaccines, Conjugate

Associated data

  • figshare/10.6084/m9.figshare.11985255