Public health impact of pneumococcal conjugate vaccine infant immunization programs: assessment of invasive pneumococcal disease burden and serotype distribution

Abstract

Introduction: Pneumococcal conjugate vaccine (PCV) impact studies have reported substantial reductions in the incidence of invasive pneumococcal disease (IPD) after implementation of childhood PCV programs. Heterogeneity in surveillance systems, local epidemiology and PCV programs hampers comparisons between studies. We aimed to better understand the impact of childhood PCV programs on overall IPD and serotype distribution. Areas covered: We analyzed the impact of PCV programs on the incidence of overall IPD, and the distribution of vaccine serotypes (VT) and non-vaccine serotypes (NVT) in children <5 years and adults ≥65 years old. We retrieved datasets from observational post-marketing studies and surveillance reports from countries with high-quality surveillance data available for at least 2 years before PCV program initiation and 3 years after higher-valent PCV implementation. We harmonized pre-and post-PCV analysis periods and assessment methods. Expert commentary: After introduction of pediatric PCV programs, the residual overall IPD burden in children was low and in a narrow range across countries with high vaccination coverage, irrespective of differences in PCV programs and pneumococcal epidemiology. Effects on overall IPD were more variable in the elderly. Whereas IPD was mainly due to VTs before PCV introduction, NVTs are the major contributor today in children and adults.ARTICLE HISTORY

Serotype and clonal distribution dynamics of invasive pneumococcal strains after PCV13 introduction (2011-2016): Surveillance data from 23 sites in Catalonia, Spain

“…A significant decrease in high invasive disease potential serotypes, such as serotypes 1, 5, 7F or 19A [26] associated in the past with important burden of disease in our country [27], supports a beneficial effect of vaccination. A decline of these invasive serotypes owed to PCV13 vaccination has been reported worldwide by other authors [28][29][30].…”

Whole Genomic Comparative Analysis of Streptococcus Pneumoniae Serotype 1 Isolates Causing Invasive and Non-Invasive Infections Among Children Under 5 years in Casablanca, Morocco

“…Pneumococcal vaccination constitutes the best option for preventing IPD, and in several countries, PCVs have been recommended in childhood immunization programs for more than a decade. They have signi cantly reduced the global IPD burden in children as reported in the review of Izurieta [7]. In Morocco, the national immunization program introduced the PCV in October 2010 rstly by PCV-13 in 2 + 1 schedule at the age of 2, 4 and 12 months, then switched to PCV-10 in July 2012 in same schedule.…”

Population-based incidence and serotype distribution of invasive pneumococcal disease prior to introduction of conjugate pneumococcal vaccine in Bangladesh

“…The preventable fraction may be lower in LMICs, such as Bangladesh [10,11]. Some countries have observed serotype replacement of pneumococcus after introduction of PCV [12][13][14][15]. To document the impact of PCV-10, it is important to document the disease burden and the serotype distribution of the pneumococcus prior to the introduction of the vaccine.…”