Effects of pneumococcal conjugate vaccine 2 years after its introduction, the Netherlands

Evolution of pneumococcal serotype epidemiology in Botswana following introduction of 13-valent pneumococcal conjugate vaccine

Pneumococcal conjugate vaccines reduce the burden of invasive pneumococcal disease, but the sustained effect of these vaccines can be diminished by an increase in disease caused by non-vaccine serotypes. To describe pneumococcal serotype epidemiology in Botswana following introduction of 13-valent pneumococcal conjugate vaccine (PCV-13) in July 2012, we performed molecular serotyping of 268 pneumococcal strains isolated from 221 children between 2012 and 2017. The median (interquartile range) age of the children included in this analysis was 6 (3,12) months. Fifty-nine percent of the children had received at least one dose of PCV-13 and 35% were fully vaccinated with PCV-13. While colonization by vaccine serotypes steadily declined following PCV-13 introduction, 25% of strains isolated more than 3 years after vaccine introduction were PCV-13 serotypes. We also observed an increase in colonization by non-vaccine serotypes 21 and 23B, which have been associated with invasive pneumococcal disease and antibiotic resistance in other settings.

Long-term population effects of infant 10-valent pneumococcal conjugate vaccination on pneumococcal meningitis in Finland

BACKGROUND

No previous studies have reported long-term follow-up of ten-valent pneumococcal conjugate vaccine (PCV10) program impact on pneumococcal meningitis (PM). We assessed the effects of infant PCV10 program on PM incidence, mortality and serotype distribution in children and adults during 7 years after introduction.

METHODS

We conducted a population-based observational study. A case of PM was defined as isolation of Streptococcus pneumoniae from cerebrospinal fluid or, a patient with S. pneumoniae isolated from blood and an ICD-10 hospital discharge diagnosis of bacterial meningitis within 30 days before or after positive culture date.We compared age- and serotype-specific incidence and associated 30-day mortality rates in 2011-2017 (PCV10 period) with those in 2004-2010 (pre-PCV10 baseline) by using Poisson regression models. Absolute rate differences and 95% confidence intervals (CIs) were calculated from the parameter estimates by using delta method.

RESULTS

During the PCV10 period, the overall incidence of PCV10 serotype meningitis decreased by 68% (95%CI 57%-77%), and the overall PM incidence by 27% (95%CI: 12%-39%). In age groups 0-4, 50-64, and ≥ 18 years, the overall PM incidence was reduced by 64%, 34% and 19%, respectively. In adults ≥ 65 years of age, a 69% reduction in PCV10 serotypes was offset by 157% (56%-342%) increase in non-PCV10 serotypes. The overall PM-related mortality rate decreased by 42% (95%CI 4%-65%). Overall case fatality proportion (CFP) was 16% in pre-PCV10 period and 12% in PCV10 period (p = 0.41); among persons 50-64 years the CFP decreased from 25% to 10% (p = 0.04).

CONCLUSIONS

We observed substantial impact and herd protection for vaccine-serotype PM and associated mortality after infant PCV10 introduction. However, in older adults ≥ 65 years of age, PM burden remains unchanged due to serotype replacement.

Similar impact and replacement disease after pneumococcal conjugate vaccine introduction in hospitalised children with invasive pneumococcal disease in Europe and North America

High incidence of childhood invasive pneumococcal disease (IPD) in the US declined steeply after 7-valent pneumococcal conjugate vaccine (PCV7) introduction, outweighing reductions observed elsewhere. We re-analysed aggregate published data and compared pre- and post-PCV IPD-incidence in different countries to explore PCV impact on hospitalised and outpatient IPD separately. The proportion of hospitalised IPD cases was consistently high (>80%) in England&Wales, Finland, the Netherlands, and Quebec/Canada, but only 32% in the US before PCV introduction, increasing to 69% during the PCV era. In the US, a higher reduction in outpatient IPD incidence (94% in 2015 versus 1998-99) was observed compared to hospitalised IPD (79%); a 51% reduction in the non-PCV13-type IPD incidence among outpatient cases was estimated compared to a >2-fold increase for hospitalised cases. After stratification by hospitalization status, PCV programmes resulted in similar impact and serotype replacement in hospitalised IPD in US when compared to other countries.

Estimating the Impact of Switching from a Lower to Higher Valent Pneumococcal Conjugate Vaccine in Colombia, Finland, and The Netherlands: A Cost-Effectiveness Analysis

INTRODUCTION

Widespread use of ten-valent (Synflorix™, GSK) or 13-valent (Prevenar 13™; Pfizer) conjugate vaccination programs has effectively reduced invasive pneumococcal disease (IPD) globally. However, IPD caused by serotypes not contained within the respective vaccines continues to increase, notably serotypes 3, 6A, and 19A in countries using lower-valent vaccines. Our objective was to estimate the clinical and economic benefit of replacing PCV10 with PCV13 in Colombia, Finland, and The Netherlands.

METHODS

Country-specific databases, supplemented with published and unpublished data, informed the historical incidence of pneumococcal disease as well as direct and indirect medical costs. A decision-analytic forecasting model was applied, and both costs and outcomes were discounted. The observed invasive pneumococcal disease (IPD) trends from each country were used to forecast the future number of IPD cases given a PCV13 or PCV10 program.

RESULTS

Over a 5-year time horizon, a switch to a PCV13 program was estimated to reduce overall IPD among 0-2 year olds by an incremental - 37.6% in Colombia, - 32.9% in Finland, and - 26% in The Netherlands, respectively, over PCV10. Adults > 65 years experienced a comparable incremental decrease in overall IPD in Colombia (- 32.2%), Finland (- 15%), and The Netherlands (- 3.7%). Serotypes 3, 6A, and 19A drove the incremental decrease in disease for PCV13 over PCV10 in both age groups. A PCV13 program was dominant in Colombia and Finland and cost-effective in The Netherlands at 1 × GDP per capita (€34,054/QALY).

CONCLUSION

In Colombia, Finland, and The Netherlands, countries with diverse epidemiologic and population distributions, switching from a PCV10 to PCV13 program would significantly reduce the burden of IPD in all three countries in as few as 5 years.

Pneumococcal Disease: A Systematic Review of Health Utilities, Resource Use, Costs, and Economic Evaluations of Interventions

BACKGROUND

Pneumococcal diseases cause substantial mortality, morbidity, and economic burden. Evidence on data inputs for economic evaluations of interventions targeting pneumococcal disease is critical.

OBJECTIVES

To summarize evidence on resource use, costs, health utilities, and cost-effectiveness for pneumococcal disease and associated interventions to inform future economic analyses.

METHODS

We searched MEDLINE, Embase, Web of Science, CINAHL, PsycINFO, EconLit, and Cochrane databases for peer-reviewed studies in English on pneumococcal disease that reported health utilities using direct or indirect valuation methods, resource use, costs, or cost-effectiveness of intervention programs, and summarized the evidence descriptively.

RESULTS

We included 383 studies: 9 reporting health utilities, 131 resource use, 160 economic costs of pneumococcal disease, 95 both resource use and costs, and 178 economic evaluations of pneumococcal intervention programs. Health state utility values ranged from 0 to 1 for both meningitis and otitis media and from 0.3 to 0.7 for both pneumonia and sepsis. Hospitalization was shortest for otitis media (range: 0.1-5 days) and longest for sepsis/septicemia (6-48). The main categories of costs reported were drugs, hospitalization, and household or employer costs. Resource use was reported in hospital length of stay and number of contacts with general practitioners. Costs and resource use significantly varied among population ages, disease conditions, and settings. Current vaccination programs for both adults and children, antibiotic use and outreach programs to promote vaccination, early disease detection, and educational programs are cost-effective in most countries.

CONCLUSION

This study has generated a comprehensive repository of health economic evidence on pneumococcal disease that can be used to inform future economic evaluations of pneumococcal disease intervention programs.

The Impact of the 13-Valent Pneumococcal Conjugate Vaccine on Pneumococcal Carriage in the Community Acquired Pneumonia Immunization Trial in Adults (CAPiTA) Study

Background

The impact of pneumococcal conjugate vaccination on the prevalence of nasopharyngeal carriage with pneumococci and other bacteria in adults is unknown. The direct effects of the 13-valent pneumococcal conjugate vaccine (PCV13) in community dwelling older adults was investigated as part of the randomized controlled Community Acquired Pneumonia immunization Trial in Adults (CAPiTA).

Methods

We determined the carriage of Streptococcus pneumoniae, Staphylococcus aureus, Haemophilus influenzae, and Moraxella catarrhalis before and 6, 12, and 24 months after vaccination using polymerase chain reaction (PCR)-based methods and conventional cultures of nasopharyngeal and oropharyngeal swab samples in 1006 PCV13 recipients and 1005 controls. Serotyping of the 13 vaccine-type (VT) pneumococci was performed by PCR targeting capsular synthesis genes and Quellung reaction of isolates.

Results

Before randomization and based on PCR, 339 of 1891 subjects had nasopharyngeal carriage with any pneumococci (17.9%), and 114 of 1891 (6.0%) carried VT pneumococci. At 6 months after vaccination, VT pneumococcal carriage was significantly lower in PCV13 recipients than in the placebo group (relative risk, 0.53; 95% confidence interval, .35-.80; P = .04). There was no difference between the groups at 12 and 24 months after vaccination. Carriage of non-VT pneumococci, S. aureus, H. influenzae, and M. catarrhalis did not change between groups.

Conclusions

In community-dwelling adults aged ≥65 years, a single dose of PCV13 seems to elicit a small and temporary reduction in VT carriage 6 months after vaccination. Neither replacement by non-VT serotypes nor impact on other nasopharyngeal bacteria was observed.

Twelve years of pneumococcal conjugate vaccination in the Netherlands: Impact on incidence and clinical outcomes of invasive pneumococcal disease

INTRODUCTION

In 2006, the Netherlands introduced the 7-valent pneumococcal conjugate vaccine (PCV7) in their national immunisation programme. In 2011, PCV7 was replaced by the 10-valent vaccine (PCV10). We report on the impact of PCV on invasive pneumococcal disease (IPD) incidence, clinical syndromes and patient outcomes.

METHODS

Pneumococcal isolates of hospitalised IPD patients between June 2004 and May 2018 were obtained from nine sentinel laboratories, covering 25% of the Dutch population. All isolates were serotyped. IPD incidence and clinical outcome were determined before and after introduction of PCV7 and after the switch to PCV10, stratified by age and serotype.

RESULTS

Compared to before PCV7 introduction, significant declines in IPD incidence were observed in 2016-2018 in children <5 years (69%), 18-49 year olds (31%) and ≥65 year olds (19%). Compared to before PCV10 introduction, the IPD incidence in 2016-2018 declined in children <5 years (RR:0.68, 95%CI:0.42-1.11), 5-17 year olds (RR:0.58, 95%CI:0.29-1.14) and 18-49 year olds (RR:0.72, 95%CI:0.57-0.90), but not in 50-64 year olds (RR:0.94, 95%CI:0.81-1.10) and ≥65 year olds (RR:1.04, 95%CI:0.0.93-1.15). While the case fatality rate (CFR) decreased from 16.2% pre-PCV to 13.4% post-PCV10 (RR:0.83, 95%CI:0.70-0.99), the switch to PCV10 had no further impact on CFR (RR:1.14, 95%CI:0.96-1.36).

CONCLUSION

Twelve years of PCV in the Netherlands has resulted in a sustained reduction of IPD incidence in children and younger adults. The switch from PCV7 to PCV10 did not have additional impact on the IPD incidence in older adults and CFR due to emerging non-vaccine serotypes.

Clonal similarities and sequence-type diversity of invasive and carriage Streptococcus pneumoniae in India among children under 5 Years

Background

Pneumococcal pneumonia is one of the major causes of mortality in children less than 5 years in Asia, especially in India. Available PCVs have less serotype coverage in India compared to western countries. Moreover, the baseline pneumococcal serotype and sequence type data is limited and available data doesn't represent the entire India. With this background we aimed to characterize invasive and carriage isolates of S. pneumoniae from a tertiary care hospital in South India.

Materials and Methods

A total of 221 S. pneumoniae isolates, invasive (n=138) and carriage (n=83) between the time period of 2012-2018 were included. Isolates was identified and confirmed using standard laboratory protocols. Serotyping was performed by Customized sequential multiplex PCR and MLST as described in www.pubmlst.org.

Results

The major serotypes were 19F, 6B, 14, 6A and 19A and the sequence types (ST) were ST63, 236 and 230. Predominant STs in invasive was ST 63 whereas in carriage were ST4894 and 1701. High level ST diversity in carriage was observed. Majority of the STs were SLVs or DLVs of previously reported STs or PMEN clones. Phylogenetic analyses of the STs revealed gradual expansion of three PMEN CCs CC320, 63 and 230.

Conclusion

The vaccine serotypes were the predominant ones found to be associated with IPD, PMEN clones, new STs and antimicrobial resistance. Accordingly, PCV13 is expected to provide invasive serotype coverage of 75% in Indian children less than 5 years. This study provides baseline serotype and sequence type data prior to the introduction of PCV in South India.

Streptococcus pneumoniae: Invasion and Inflammation

Streptococcus pneumoniae (the pneumoccus) is the leading cause of otitis media, community-acquired pneumonia, and bacterial meningitis. The success of the pneumococcus stems from its ability to persist in the population as a commensal and avoid killing by immune system. This chapter first reviews the molecular mechanisms that allow the pneumococcus to colonize and spread from one anatomical site to the next. Then, it discusses the mechanisms of inflammation and cytotoxicity during emerging and classical pneumococcal infections.

Pneumococcal vaccine impacts on the population genomics of non-typeable Haemophilus influenzae

The implementation of pneumococcal conjugate vaccines (PCVs) has led to a decline in vaccine-type disease. However, there is evidence that the epidemiology of non-typeable Haemophilus influenzae (NTHi) carriage and disease can be altered as a consequence of PCV introduction. We explored the epidemiological shifts in NTHi carriage using whole genome sequencing over a 5-year period that included PCV13 replacement of PCV7 in the UK’s National Immunization Programme in 2010. Between 2008/09 and 2012/13 (October to March), nasopharyngeal swabs were taken from children <5 years of age. Significantly increased carriage post-PCV13 was observed and lineage-specific associations with Streptococcus pneumoniae were seen before but not after PCV13 introduction. NTHi were characterized into 11 discrete, temporally stable lineages, congruent with current knowledge regarding the clonality of NTHi. The increased carriage could not be linked to the expansion of a particular clone and different co-carriage dynamics were seen before PCV13 implementation when NTHi co-carried with vaccine serotype pneumococci. In summary, PCV13 introduction has been shown to have an indirect effect on NTHi epidemiology and there exists both negative and positive, distinct associations between pneumococci and NTHi. This should be considered when evaluating the impacts of pneumococcal vaccine design and policy.

Current status and future directions of invasive pneumococcal diseases and prophylactic approaches to control them

Streptococcus pneumoniae is a major human bacterial pathogen responsible for millions of deaths each year and significantly more illnesses worldwide. With over 90 different serotypes, providing effective vaccine programs has been a continuing challenge. Since 1983, the world has been introduced to four different pneumococcal vaccines (PPSV23, PCV7, PCV10, and PCV13) each with their own complications and successes. Since vaccination programs began, a decrease in the overall rate of pneumococcal pneumonia and associated diseases has been observed, notably in higher risk populations. However, with a decrease in incidence of vaccine type pneumococcal serotypes, increases in non-vaccine serotypes of the bacteria have been observed along with serotype switching. Additionally, a rise in antibiotic resistant strains of S. pneumoniae is noted. Here we discuss both the positive and negative clinical manifestations of pneumonia vaccine programs and discuss the challenges in pneumococcal vaccine design.

Potential impact of introducing the pneumococcal conjugate vaccine into national immunisation programmes: an economic-epidemiological analysis using data from India

Pneumococcal pneumonia causes an estimated 105 000 child deaths in India annually. The planned introduction of the serotype-based pneumococcal conjugate vaccine (PCV) is expected to avert child deaths, but the high cost of PCV relative to current vaccines provided under the Universal Immunization Programme has been a concern. Cost-effectiveness studies from high-income countries are not readily comparable because of differences in the distribution of prevalent serotypes, population and health systems. We extended IndiaSim, our agent-based simulation model representative of the Indian population and health system, to model the dynamics of Streptococcus pneumoniae. This enabled us to evaluate serotype and overall disease dynamics in the context of the local population and health system, an aspect that is missing in prospective evaluations of the vaccine. We estimate that PCV13 introduction would cost approximately US$240 million and avert US$48.7 million in out-of-pocket expenditures and 34 800 (95% CI 29 600 to 40 800) deaths annually assuming coverage levels and distribution similar to DPT (diphtheria, pertussis and tetanus) vaccination (~77%). Introducing the vaccine protects the population, especially the poorest wealth quintile, from potentially catastrophic expenditure. The net-present value of predicted money-metric value of insurance for 20 years of vaccination is US$160 000 (95% CI US$151 000 to US$168 000) per 100 000 under-fives, and almost half of this protection is for the bottom wealth quintile (US$78 000; 95% CI 70 800 to 84 400). Extending vaccination to 90% coverage averts additional lives and provides additional financial risk protection. Our estimates are sensitive to immunity parameters in our model; however, our assumptions are conservative, and if willingness to pay per years of life lost averted is US$228 or greater, then introducing the vaccine is more cost-effective than our baseline (no vaccination) in more than 95% of simulations.

Triptych of the Hermit Saints: pneumococcal polysaccharide vaccines for the elderly

Pneumococcal pneumonia is a serious disease with considerable morbidity and mortality in the elderly. Despite adequate antibiotic treatment, the long-term mortality of pneumococcal pneumonia remains high. Preventive measures in the form of vaccination, therefore, are warranted. Twenty-three-valent polysaccharide vaccines have a broad coverage but limited efficacy. Pneumococcal conjugate vaccines have been shown in children to be able to prevent invasive and mucosal pneumococcal diseases. It should be realized that the serotype composition of current pneumococcal conjugate vaccines is not tailored for the elderly, and that replacement disease can occur. Yet, the current 13-valent conjugate vaccine has been shown to protect against infections with vaccine serotypes. Long-term mortality of pneumococcal pneumonia should be included in policy making about the introduction of these vaccines for the elderly.

Strain Level Streptococcus Colonization Patterns during the First Year of Life

Pneumococcal pneumonia has decreased significantly since the implementation of the pneumococcal conjugate vaccine (PCV), nevertheless, in many developing countries pneumonia mortality in infants remains high. We have undertaken a study of the nasopharyngeal (NP) microbiome during the first year of life in infants from The Philippines and South Africa. The study entailed the determination of the Streptococcus sp. carriage using a lytA qPCR assay, whole metagenomic sequencing, and in silico serotyping of Streptococcus pneumoniae, as well as 16S rRNA amplicon based community profiling. The lytA carriage in both populations increased with infant age and lytA+ samples ranged from 24 to 85% of the samples at each sampling time point. We next developed informatic tools for determining Streptococcus community composition and pneumococcal serotype from metagenomic sequences derived from a subset of longitudinal lytA-positive Streptococcus enrichment cultures from The Philippines (n = 26 infants, 50% vaccinated) and South African (n = 7 infants, 100% vaccinated). NP samples from infants were passaged in enrichment media, and metagenomic DNA was purified and sequenced. In silico capsular serotyping of these 51 metagenomic assemblies assigned known serotypes in 28 samples, and the co-occurrence of serotypes in 5 samples. Eighteen samples were not typeable using known serotypes but did encode for capsule biosynthetic cluster genes similar to non-encapsulated reference sequences. In addition, we performed metagenomic assembly and 16S rRNA amplicon profiling to understand co-colonization dynamics of Streptococcus sp. and other NP genera, revealing the presence of multiple Streptococcus species as well as potential respiratory pathogens in healthy infants. A range of virulence and drug resistant elements were identified as circulating in the NP microbiomes of these infants. This study revealed the frequent co-occurrence of multiple S. pneumoniae strains along with Streptococcus sp. and other potential pathogens such as S. aureus in the NP microbiome of these infants. In addition, the in silico serotype analysis proved powerful in determining the serotypes in S. pneumoniae carriage, and may lead to developing better targeted vaccines to prevent invasive pneumococcal disease (IPD) in these countries. These findings suggest that NP colonization by S. pneumoniae during the first years of life is a dynamic process involving multiple serotypes and species.

Changes in pathogens and pneumococcal serotypes causing community-acquired pneumonia in The Netherlands

BACKGROUND

In 2006 a 7-valent pneumococcal conjugate vaccine (PCV7) was introduced in the immunisation programme for infants in The Netherlands and replaced by PCV10 in 2011. Limited data exist about the impact of PCV on the aetiology of CAP as a whole. The aim of the present study is to describe the overall changes in microbial aetiology, pneumococcal burden (including non-bacteraemic pneumococcal pneumonia) and its serotypes in adult community-acquired pneumonia (CAP) after the introduction of these PCVs.

METHODS

Hospitalised adult CAP patients who participated in three consecutive trials were studied (2004-2006 (n=201), 2007-2009 (n=304) and 2012-2016 (n=300) and considered as pre-PCV7, PCV7 and PCV10 period). Extensive conventional microbiological testing was applied for all patients. In addition, patients with a serotype-specific pneumococcal antibody response were diagnosed with pneumococcal CAP. Changes in proportions of causative pathogens and distributions of pneumococcal serotypes were calculated.

RESULTS

The proportion of pneumococcal CAP decreased from 37% (n=74/201) to 26% (n=77/300) comparing the pre-PCV7 period with the PCV10 period (p=0.01). For other pathogens, including Legionella spp., Mycoplasma pneumoniae, S. aureus, H. influenzae, and respiratory viruses, no sustained shifts were observed in their relative contribution to the aetiology of CAP. Within the pneumococcal CAP patients, we observed a decrease in PCV7 and an increase in non-PCV10 serotype disease. PCV10-extra type disease did not decrease significantly comparing the PCV10 period with the pre-PCV7 and PCV7 period, respectively. Notably, PCV7 type disease decreased both in bacteraemic and non-bacteraemic patients.

CONCLUSIONS

Our findings confirm that PCV introduction in infants impact the microbial aetiology of adult CAP and suggest herd effects in adults with CAP after introduction of PCVs in children.

Sex differences in invasive pneumococcal disease and the impact of pneumococcal conjugate vaccination in the Netherlands, 2004 to 2015

Implementation of pneumococcal conjugate vaccines in the Netherlands (PCV7 in 2006 and PCV10 in 2011) for infants caused a shift in serotypes in invasive pneumococcal disease (IPD). We explored sex differences in serotype-specific IPD incidence before and after vaccine introduction. Incidences in the pre-PCV7 (June 2004–May 2006), post-PCV7 (June 2008–May 2011) and post-PCV10 period (June 2013–May 2015), stratified by age, were compared. Incidence was higher in men for all age groups (overall in men: 16.7, 15.5 and 14.4/100,000 and women: 15.4, 13.6 and 13.9/100,000 pre-PCV7, post-PCV7 and post-PCV10, respectively), except for 20–39 year-olds after PCV7 and 40–64 year-olds after PCV10 introduction. After PCV7 and PCV10 introduction, the overall IPD incidence decreased in men aged 20–39 years (from 5.3 pre-PCV7 to 4.7 and 2.6/100,000 post-PCV7 and post-PCV10, respectively), whereas it showed a temporary increase in women (from 3.9/100,000 pre-PCV7 to 5.0/100,000 post-PCV7 and back to 4.0/100,000 post-PCV10) due to replacement disease. PCV10 herd effects were observed throughout, but in women older than 40 years, a significant increase in non-PCV10 serotype offset a decrease in overall IPD incidence. Ongoing surveillance of IPD incidence by sex is important to evaluate the long-term effects of PCV implementation.

Modeling the cost-effectiveness of infant vaccination with pneumococcal conjugate vaccines in Germany

BACKGROUND

In 2009, the European Medicines Agency granted approval for two higher-valent pneumococcal conjugate vaccines. This study aims to evaluate the cost-effectiveness of universal infant (<2 years old) vaccination with a 13-valent pneumococcal conjugate vaccine (PCV13) in comparison with a 10-valent pneumococcal conjugate vaccine (PCV10) for the prevention of pneumococcal disease in Germany.

METHODS

A population-based Markov model was developed to estimate the impact of PCV13 and PCV10 on invasive pneumococcal disease (IPD), non-invasive pneumonia (PNE), and acute otitis media (AOM) over a time horizon of 50 years. The model included the effects of the historical vaccination scheme in infants as well as indirect herd effects and replacement disease. We used German epidemiological data to calculate episodes of IPD, PNE, and AOM, as well as direct and indirect effects of the vaccination. Parameter uncertainty was tested in univariate and probabilistic sensitivity analyses.

RESULTS

In the base-case analysis, the ICER of PCV13 versus PCV10 infant vaccination was EUR 9826 per quality-adjusted life-year (QALY) gained or EUR 5490 per life-year (LY) gained from the societal perspective and EUR 3368 per QALY gained or EUR 1882 per LY gained from the perspective of the German statutory health insurance. The results were particularly sensitive to the magnitude of indirect effects of both vaccines.

CONCLUSIONS

Universal infant vaccination with PCV13 is likely to be a cost-effective intervention compared with PCV10 within the German health care system, if additional net indirect effects of PCV13 vaccination are significant.

Changing trends in serotypes of S. pneumoniae isolates causing invasive and non-invasive diseases in unvaccinated population in Mexico (2000-2014)

OBJECTIVE

Introduction of pneumococcal conjugate vaccines (PCV) targeted against a limited number of serotypes substantially decreased invasive (IPD) and non-invasive pneumococcal diseases (NIPD) but it was accompanied by non-vaccine type replacement disease. After 9 years of introduction of PCV in Mexico, we analyze the evidence of the indirect effects on IPD and NIPD serotype distribution among groups not targeted to receive the vaccine.

METHODS

From January 2000 to December 2014, pneumococcal strains isolated from IPD and NIPD cases from patients ≥5 years of age from participant hospitals of the SIREVA II (Sistema Regional de Vacunas) network were serotyped. A regression analysis was performed considering year and proportion of serotypes included in the different vaccine formulations (PCV7, PCV10 and PCV13). The slope was obtained for each regression line and their correspondent p-value. The proportion of each serotype in the pre-PCV7 and post-PCV7 periods was evaluated by χ2 test.

RESULTS

From a total of 1147 pneumococcal strains recovered, 570 corresponded to the pre-PCV7 and 577 to the post-PCV7 periods. The proportion of vaccine serotypes included in the three PCV formulations decreased by 2.4, 2.6 and 1.3%, respectively per year during the study period. A significant increase of serotype 19A was observed in the post-vaccine period in all age groups.

CONCLUSIONS

A percentage of annual decline of serotypes causing IPD and NIPD included in PCV was detected among groups not targeted to receive the vaccine, probably due to herd effect. Considering pneumococcal serotype distribution is a dynamic process, we highlight the importance of surveillance programs.

Cost-effectiveness of 13-valent pneumococcal conjugate vaccination in Mongolia

Objective

The Ministry of Health (MOH), Mongolia, is considering introducing 13-valent pneumococcal conjugate vaccine (PCV13) in its national immunization programme to prevent the burden of disease caused by Streptococcus pneumoniae. This study evaluates the cost-effectiveness and budget impact of introducing PCV13 compared to no PCV vaccination in Mongolia.

Methods

The incremental cost-effectiveness ratio (ICER) of introducing PCV13 compared to no PCV vaccination was assessed using an age-stratified static multiple cohort model. The risk of various clinical presentations of pneumococcal disease (meningitis, pneumonia, non-meningitis non-pneumonia invasive pneumococcal disease and acute otitis media) at all ages for thirty birth cohorts was assessed. The analysis considered both health system and societal perspectives. A 3 + 0 vaccine schedule and price of US$3.30 per dose was assumed for the baseline scenario based on Gavi, the Vaccine Alliance’s advance market commitment tail price.

Results

The ICER of PCV13 introduction is estimated at US$52 per disability-adjusted life year (DALY) averted (health system perspective), and cost-saving (societal perspective). Although indirect effects of PCV have been well-documented, a conservative scenario that does not consider indirect effects estimated PCV13 introduction to cost US$79 per DALY averted (health system perspective), and US$19 per DALY averted (societal perspective). Vaccination with PCV13 is expected to cost around US$920,000 in 2016, and thereafter US$820,000 every year. The programme is likely to reduce direct disease-related costs to MOH by US$440,000 in the first year, increasing to US$510,000 by 2025.

Conclusion

Introducing PCV13 as part of Mongolia’s national programme appears to be highly cost-effective when compared to no vaccination and cost-saving from a societal perspective at vaccine purchase prices offered through Gavi. Notwithstanding uncertainties around some parameters, cost-effectiveness of PCV introduction for Mongolia remains robust over a range of conservative scenarios. Availability of high-quality national data would improve future economic analyses for vaccine introduction.

Impact of PCV7/PCV13 introduction on invasive pneumococcal disease (IPD) in young children: Comparison between meningitis and non-meningitis IPD

BACKGROUND

The worldwide introduction of pneumococcal conjugate vaccines (PCV) into National Immunization Programs resulted in rapid and substantial reduction of invasive pneumococcal disease (IPD) rates in children. However, the reduction of meningitis vs. non-meningitis IPD (nm-IPD) was not yet fully elucidated. We compared 7-valent and 13-valent PCV (PCV7 and PCV13) impact on pneumococcal-meningitis vs. nm-IPD in Israeli children <5years.

METHODS

We conducted an ongoing nationwide, prospective, population-based, active surveillance. PCV7 and PCV13 were implemented in Israel in July 2009 and November 2010, respectively. All pneumococcal isolates (blood and/or CSF) from IPD episodes in children <5years from July 2000 through June 2015 were included. Extrapolation for missing serotypes (34.7% of all isolates) was conducted.

RESULTS

4163 IPD cases were identified; 3739nm-IPD (89.8%) and 424 meningitis (10.2%). During the pre-PCV period (2000-2008), children <12months constituted 52.1% and 33.7% of meningitis and nm-IPD, respectively (p<0.001). The respective proportions of non-PCV13 serotypes (non-VT) were 18.2% vs. 10.1%, (p<0.001). Comparing the last study year (2014-2015) to the mean of pre-PCV period, meningitis incidence in children <5years decreased non-significantly by 27%, while nm-IPD decreased significantly by 69%. Dynamic rates of meningitis and nm-IPD caused by PCV13 serotypes were similar, with 93% and 95% overall reductions, respectively. However, non-VT increased in meningitis relatively to nm-IPD, mainly in children <24months. Serotype 12F rose sharply and significantly since 2009-2010 through 2014-2015 (28.6% of all non-VT meningitis in children <24m).

CONCLUSIONS

The overall impact of PCV7/PCV13 in children <5years in Israel was less prominent in meningitis than in nm-IPD. This could be attributed to the younger age of children with meningitis and differences in causative serotypes between the two groups, as the decline of the incidence of meningitis and nm-IPD caused by vaccine-serotypes is similar. Continuous monitoring of meningitis and nm-IPD is warranted.

Pneumococcus and the Elderly in Italy: A Summary of Available Evidence Regarding Carriage, Clinical Burden of Lower Respiratory Tract Infections and On-Field Effectiveness of PCV13 Vaccination

Streptococcus pneumoniae is currently the leading cause of community-acquired pneumonia (CAP) and lower respiratory tract infections (LRTI) in adults, elderly and high-risk subjects worldwide. The clear benefits of pneumococcal conjugate vaccination in childhood have been accompanied by a decrease of vaccine-serotype invasive diseases among adults in several countries, mainly due to the herd effect mediated by the reduction of vaccine-serotype nasopharyngeal colonization in both age groups, but this reduction in the incidence of pneumonia has not been observed. The "Community Acquired Pneumonia Immunization Trial in Adults" (CAPITA) study provided conclusive evidence about 13-valent pneumococcal conjugate vaccine (PCV13) efficacy in preventing CAP in adults and led Western countries to issue new recommendations for pneumococcal immunization targeting subjects >50 years and high-risk groups, with marked differences with respect to age and/or risk groups immunized, eligibility for reimbursement and national, regional or local implementation. Several Italian regions implemented PCV13 immunization programs in adults and interesting data have been come available in the last years, especially from Liguria, a Northern region with a high and long-lasting pneumococcal vaccine immunological pressure in infants. In this review, currently available evidence from Italy and Liguria regarding pneumococcal carriage, burden of CAP and LRTI, and on-field effectiveness of PCV13 immunization in adults and elderly will be summarized.

Serotype distribution and penicillin-non-susceptibility of Streptococcus pneumoniae causing invasive diseases in Kuwait: A 10-year study of impact of pneumococcal conjugate vaccines

OBJECTIVES

The impact of PCV7 and PCV13 on pneumococcal infections in Kuwait is not known. Therefore we evaluated the impact on pneumococcal serotype distribution and penicillin-non-susceptibility in invasive infections in Kuwait.

METHODS

Children < 2 y were given PCV7 from Aug 2006 to Jul 2010 (period I), and PCV13 from Aug 2010 to Jul 2013 (period II) with a pre-vaccination period from Aug 2003 to Jul 2006. Serotype and penicillin-non-susceptibility of blood and cerebrospinal fluid isolates from all ages were determined.

RESULTS

In <2 y old children, even with a small number of infections, a drop in PCV7 serotypes was evident after vaccination. For all age groups combined, in the pre-vaccination period, PCV7, PCV13, PCV13 non-PCV7 serotypes and penicillin-non-susceptibility constituted 53.2%, 72.6%, 19.4% and 6.5% of the isolates respectively. PCV7, PCV13 non-PCV7 serotypes and penicillin-non-susceptibility changed to 32.7%, 28.2% and 7.3% (period I) and 6.6%, 22.2% and 8.9% (period II).

CONCLUSIONS

Vaccines reduced invasive infections due to PCV7 serotypes.

Invasive Pneumococcal Disease 3 Years after Introduction of 10-Valent Pneumococcal Conjugate Vaccine, the Netherlands

Three years after a 7-valent pneumococcal conjugate vaccine was replaced by a 10-valent pneumococcal conjugate vaccine in the Netherlands, we observed a decrease in incidence of invasive pneumococcal disease caused by Streptococcus pneumoniae serotypes 1, 5, and 7F. Our data do not support or exclude cross-protection against serotype 19A.

Active hospital-based surveillance of invasive pneumococcal disease and clinical pneumonia in infants and young children in two Polish counties

INTRODUCTION

Invasive pneumococcal disease (IPD) incidence, serotype distribution, and antibiotic susceptibility of Streptococcus pneumoniae were estimated in children aged 28 days to < 60 months.

MATERIAL AND METHODS

One-year prospective, hospital-based surveillance was conducted starting on February 15, 2008, at two children's hospitals serving the city and surrounding county of Poznań and Poznański, Poland. Eligible children had fever ≥ 39.0°C or physician-suspected IPD. Blood cultures were obtained from all children, cerebrospinal fluid in suspected meningitis cases, and chest radiographs (CXRs) in suspected pneumonia cases.

RESULTS

Seven of 1,581 eligible children had confirmed IPD. Estimated IPD incidence per 100,000 children was 11.89 (95% CI: 4.78-24.50) overall and 20.1 (95% CI: 6.52-46.84) in subjects aged 28 days to < 24 months. One S. pneumoniae isolate of each of the following serotypes was obtained: 6B, 14, 23A, 23F, and 33F. Two isolates were resistant to both trimethoprim-sulfamethoxazole and erythromycin. Clinical pneumonia incidence among children aged 28 days to < 24 months and 24 months to < 60 months was 3,151.3 (95% CI: 2934.7-3379.7) and 962.7 (95% CI: 861.2-10,072.9) per 100,000 children, respectively. CXR-confirmed pneumonia rates in the same groups were 1,035.7 (95% CI: 913.2-1,170.1) and 379.8 (95% CI: 317.1-451.3) per 100,000 children, respectively.

CONCLUSIONS

IPD is an important cause of morbidity in Poznań and Poznański county, Poland. Among participants aged < 5 years with fever or suspected IPD, pneumonia was the most common diagnosis and was highest in children aged < 24 months.

Population Structure of Streptococcus pneumoniae Causing Invasive Disease in Adults in Portugal before PCV13 Availability for Adults: 2008-2011

Among the 1660 isolates recovered from invasive pneumococcal disease (IPD) in adults (> = 18 yrs) in 2008–2011, a random sample of ≥50% of each serotype (n = 871) was chosen for MLST analysis and evaluation for the presence and type of pilus islands (PIs). The genetic diversity was high with 206 different sequence types (STs) detected, but it varied significantly between serotypes. The different STs represented 80 clonal complexes (CCs) according to goeBURST with the six more frequent accounting for more than half (50.6%) of the isolates—CC156 (serotypes 14, 9V and 23F), CC191 (serotype 7F), CC180 (serotype 3), CC306 (serotype 1), CC62 (serotypes 8 and 11A) and CC230 (serotype 19A). Most of the isolates (n = 587, 67.3%) were related to 29 Pneumococcal Molecular Epidemiology Network recognized clones. The overall proportion of isolates positive for any of the PIs was small (31.9%) and declined gradually during the study period (26.6% in 2011), mostly due to the significant decline of serotype 1 which is associated with PI-2. The changes in serotypes that occurred in adult IPD after the introduction of the seven-valent pneumococcal conjugate vaccine (PCV7) for children were mostly due to the expansion of previously circulating clones, while capsular switching was infrequent and not related to vaccine use. The reduction of IPD caused by PCV7 serotypes in the years following PCV7 implementation did not result in a decline of antimicrobial resistance in part due to the selection of resistant genotypes among serotypes 14 and 19A.

Pneumococcal conjugate vaccine herd effects on non-invasive pneumococcal pneumonia in elderly

BACKGROUND

Herd protection from infant pneumococcal conjugate vaccination is well established for invasive pneumococcal disease (IPD) but not for non-IPD pneumococcal community-acquired pneumonia (PCAP). We assessed the contribution of vaccine-serotypes in non-IPD PCAP in adults 65 years and older in the period 2008-2013.

METHODS

This is a post hoc analysis of two prospective studies from the Netherlands. Serotype specific urinary antigen detection and routine microbiological testing were used to categorize episodes as IPD or non-IPD PCAP caused by 7-valent pneumococcal conjugate vaccine (PCV7), PCV10-7 (three additional PCV10 serotypes), PCV13-10 (three additional PCV13 serotypes), and non-PCV13 serotypes. Proportions per vaccine-serotype group were assessed per year from June 1st to May 31st. Time trends were compared to national IPD data.

RESULTS

Of 270 non-IPD PCAP episodes with known serotype, PCV7 serotypes decreased from 28% in 2008/2009 to 7% in 2012/2013 (p-value for trend <0.001). No change in PCV10-7 (19% overall) and PCV13-10 (29% overall) serotypes was observed. Non-PCV13 serotypes increased from 30% in 2008/2009 to 37% in 2012/2013 (p-value for trend 0.048). Trends corresponded with national IPD data.

CONCLUSION

PCV7 serotypes declined in non-IPD PCAP among elderly between 2008 and 2013, comparable to IPD data. No reduction in the additional PCV10 serotypes could be demonstrated within the first two years after PCV10 introduction.

Invasive pneumococcal disease: Clinical outcomes and patient characteristics 2-6 years after introduction of 7-valent pneumococcal conjugate vaccine compared to the pre-vaccine period, the Netherlands

BACKGROUND

Implementation of 7-valent pneumococcal conjugate vaccine (PCV7) in the Dutch national immunization program for infants led to a shift from vaccine to non-vaccine serotypes in invasive pneumococcal disease (IPD) in all age groups. We studied the impact of the serotype shift on clinical syndromes and outcomes.

METHODS

Pneumococcal isolates from hospitalized IPD patients obtained from nine sentinel microbiology laboratories, covering 25% of the Dutch population, were serotyped. Clinical syndromes, outcomes and patient characteristics in the post-PCV7 (2008-2012) period were compared with the pre-PCV7 period (2004-2006). Serotype specific propensity of the association with empyema, meningitis and death was calculated.

RESULTS

Invasive pneumonia incidence significantly decreased in children <5 years and elderly ≥65 years, but increased in 5-64 years old from 4.92 to 5.58 cases/100.000/year (RR 1.13 95% CI 0.99-1.29). Empyema incidence significantly increased in elderly 65 years and older from 0.61 to 2.60 cases/100.000/year (RR 4.28 95% CI 1.97-9.33), mainly due to serotype 1. The incidence of meningitis only declined significantly in children <5 years. IPD case-fatality decreased in children <5 years from 5% to 3%, in 5-64 years old from 9% to 7% and in elderly ≥65 years significantly from 22% to 17%, due to lower case-fatality rates for most emerging non-PCV7 serotypes.

CONCLUSIONS

An increase in empyema incidence was observed in persons ≥65 years old in the post-PCV7 era, mainly due to the emergence of serotype 1, although overall IPD case-fatality decreased. Extended conjugate vaccines that target serotype 1 or serotypes with high case-fatality may offer further reduction of pneumococcal disease burden.

Pneumococcal population in the era of vaccination: changes in composition and the relation to clinical outcomes

BACKGROUND

Vaccination of infants with pneumococcal conjugate vaccines (PCV) has resulted in major shifts in circulating serotypes.

AIM

To investigate the impact of PCV7 on the clonal composition of the pneumococcal population, and the relation of clonal lineages and clinical outcome.

MATERIALS & METHODS

By using multiple-locus variable number of tandem repeat analysis, we assessed the pneumococcal populations before (n = 1154), 2-3 years after (n = 1190) and 4-6 years after (n = 1244) the introduction of PCV7 in The Netherlands.

RESULTS

We found statistically significant shifts in clonal lineages within serotypes 1 and 12F based on multiple-locus variable number of tandem repeat analysis results after the implementation of PCV7. Within serotype 12F, the increasing clonal lineage was significantly more associated with pneumonia.

CONCLUSION

Shifts in clonal lineages within serotypes could impact the outcomes of pneumococcal disease and fill the niche of the vaccine serotypes.

Direct Comparison of Immunogenicity Induced by 10- or 13-Valent Pneumococcal Conjugate Vaccine around the 11-Month Booster in Dutch Infants

BACKGROUND & AIMS

Since 2009/10, a 10- and a 13-valent pneumococcal conjugate vaccine (PCV) are available, but only the 10-valent vaccine is now being used for the children in the Netherlands. As the vaccines differ in number of serotypes, antigen concentration, and carrier proteins this study was designed to directly compare quantity and quality of the antibody responses induced by PCV10 and PCV13 before and after the 11-month booster.

METHODS

Dutch infants (n = 132) were immunized with either PCV10 or PCV13 and DTaP-IPV-Hib-HepB at the age of 2, 3, 4 and 11 months. Blood samples were collected pre-booster and post-booster at one week and one month post-booster for quantitative and qualitative immunogenicity against 13 pneumococcal serotypes, as well as quantitative immunogenicity against diphtheria, tetanus, pertussis and Haemophilus influenzae type b. We compared immunogenicity induced by PCV13 and PCV10 for their ten shared serotypes.

RESULTS

One month post-booster, pneumococcal serotype-specific IgG geometric mean concentrations (GMCs) for the PCV13 group were higher compared with the PCV10 group for six serotypes, although avidity was lower. Serotype 19F showed the most distinct difference in IgG and, in contrast to other serotypes, its avidity was higher in the PCV13 group. One week post-booster, opsonophagocytosis for serotype 19F did not differ significantly between the PCV10- and the PCV13 group.

CONCLUSION

Both PCV10 and PCV13 were immunogenic and induced a booster response. Compared to the PCV10 group, the PCV13 group showed higher levels for serotype 19F GMCs and avidity, pre- as well as post-booster, although opsonophagocytosis did not differ significantly between groups. In our study, avidity is not correlated to opsonophagocytotic activity (OPA) and correlations between IgG and OPA differ per serotype. Therefore, besides assays to determine IgG GMCs, assays to detect opsonophagocytotic activity, i.e., the actual killing of the pneumococcus, are important for PCV evaluation. How differences between the two vaccines relate to long-term protection requires further investigation.

TRIAL REGISTRATION

www.trialregister.nl NTR3069.

Nasopharyngeal carriage of Streptococcus pneumoniae and other bacteria in the 7th year after implementation of the pneumococcal conjugate vaccine in the Netherlands

After introduction of the 7-valent pneumococcal conjugate vaccine (PCV7) in the infant national immunization program (NIP) in the Netherlands in 2006, Streptococcus pneumoniae strains of the non-vaccine serotype 19A emerged and became the dominant serotype in carriage in children and their parents. Similar patterns were observed in other European countries and the United States. Increases in carriage rates of Staphylococcus aureus and non-typeable (NT) Haemophilus influenzae were also observed. After switching of PCV7 to 10-valent vaccine (PCV10) in 2011, a new carriage surveillance study was performed in the winter of 2012/2013. Nasopharyngeal carriage of S. pneumoniae, H. influenzae, S. aureus, and Moraxella catarrhalis was determined by conventional culture in 330 PCV10-vaccinated 11-month-old children, 330 PCV7-vaccinated 24-month-old children, and their parents. Carriage prevalence was compared with similar carriage studies conducted in 2005, 2009, and 2010/2011. Although serotype 19A remained the most frequently carried pneumococcal serotype in children, prevalence of 19A significantly declined in PCV7-vaccinated 24-month-old children (14% to 8%, p=0.01), but less in PCV10-vaccinated 11-month-old children (12% to 9%, p=0.31). Carriage of H. influenzae remained stable at an elevated level (65% in 11-month-olds and 69% in 24-month-olds), while the carriage of S. aureus returned to pre-PCV7 levels in 11-month-old children (14% in 2010/2011 to 7% in 2012/2013), but not in 24-month-olds (remained at 7%). Our results might indicate a new balance between replacing non-vaccine pneumococcal serotypes and other potential pathogenic bacteria in nasopharyngeal carriage. Carriage studies are valuable tools in assessing vaccine effects on pathogens circulating in the population, for evaluation of PCV impact, and in predicting changes in respiratory and invasive disease.

Community-acquired bacterial meningitis in adults in the Netherlands, 2006-14: a prospective cohort study

BACKGROUND

We studied causative pathogens, clinical characteristics, and outcome of adult community-acquired bacterial meningitis after the introduction of adjunctive dexamethasone treatment and nationwide implementation of paediatric conjugate vaccines.

METHODS

In this cohort study, we prospectively assessed adults (age >16 years) with community-acquired bacterial meningitis in the Netherlands, identified through the National Reference Laboratory for Bacterial Meningitis or individual physicians between Jan 1, 2006, and July 1, 2014. We identified independent predictors of an unfavourable outcome (Glasgow Outcome Scale score 1-4) by logistic regression.

FINDINGS

We assessed 1412 episodes of community-acquired bacterial meningitis. Incidence declined from 1·72 cases per 100,000 adults per year in 2007-08, to 0·94 per 100,000 per year in 2013-14. Streptococcus pneumoniae caused 1017 (72%) of 1412 episodes. Rates of adult bacterial meningitis decreased most sharply among pneumococcal serotypes included in paediatric conjugate vaccine, and in meningococcal meningitis. We found no evidence of serotype or serogroup replacement. The overall case fatality rate was 244 (17%) of 1412 episodes and unfavourable outcome occurred in 531 (38%) of 1412 episodes. Predictors of unfavourable outcome were advanced age, absence of otitis or sinusitis, alcoholism, tachycardia, lower score on the Glasgow Coma Scale, cranial nerve palsy, a cerebrospinal fluid white-cell count lower than 1000 cells per μL, a positive blood culture, and a high serum C-reactive protein concentration. Adjunctive dexamethasone was administered for 1234 (89%) of 1384 assessed episodes. The multivariable adjusted odds ratio of dexamethasone treatment for unfavourable outcome was 0·54 (95% CI 0·39-0·73).

INTERPRETATION

The incidence of adult bacterial meningitis has decreased substantially, which is partly explained by herd protection by paediatric conjugate vaccines. Adjunctive dexamethasone treatment was associated with substantially improved outcome.

FUNDING

European Research Council, National Institute of Public Health and the Environment, European Union, Academic Medical Center, and Netherlands Organization for Health Research and Development.

Risk and outcomes of invasive pneumococcal disease in adults with underlying conditions in the post-PCV7 era, The Netherlands

BACKGROUND

Immunocompromising conditions and advanced age (≥65 years) are associated with a high risk for invasive pneumococcal disease (IPD). We investigated the risk and outcomes of IPD in adults with underlying conditions in the post-PCV7 era in The Netherlands.

METHODS

IPD data from 2008 to 2012 was obtained from the national pneumococcal surveillance system, covering 25% of the Dutch population. Population estimates of underlying conditions were derived from the primary care data (2012). IPD incidence in adults with immunocompromising conditions (high risk group) and non-immunocompromising comorbidities (medium risk group) were compared to the "normal risk group" without diagnosed comorbidities. Case-fatality and ICU admission in the different risk groups was analyzed by logistic regression. Serotype specific propensities to affect high risk group IPD patients were calculated.

RESULTS

Adults with a high risk condition have a 18-fold (95% CI 15.6-21.2) and 3-fold (95% CI 2.6-3.9) higher risk compared to the normal risk group for IPD at age 18-64 years and 65 years and older, respectively. In case of a medium risk condition, the risk is 5-fold (95% CI 4.3-5.7) and 2-fold (95% CI 1.9-2.6) higher in age groups 18-64 and ≥65 years old. Likewise, IPD patients with a high or medium risk condition have a higher case-fatality (after adjustment for age, odds ratio: 2-fold (95% CI 1.5-3.5) and 1.4-fold (95% CI 1.0-2.1), respectively). Several serotypes (e.g. 6A, 6B, 23A and 23B) are associated with a significantly higher propensity to cause disease in high risk patients.

CONCLUSIONS

The risk for IPD and death in the post-PCV7 era has remained considerably high in adults and elderly with underlying conditions. The identification of serotypes with a high propensity to affect risk groups can be important for selecting (future) vaccine serotypes.

Longitudinal DRG-based survey of all-cause and pneumococcal pneumonia and meningitis for inpatients in France (2005-2010)

OBJECTIVE

This population-based retrospective study quantified the burden of all-cause and pneumococcal pneumonia and meningitis in the Rhône-Alpes region of France from 2005 to 2010, when the 7-valent pneumococcal conjugate vaccine uptake increased from 50 to>90% in children.

PATIENTS AND METHODS

Hospital admission data was obtained from the French Diagnosis Related Groups program database (French acronym PMSI). Patients were residents of the Rhône-Alpes region hospitalized for the diseases of interest during 2005-2010. Hospitalization and in-hospital mortality rates were calculated by age, sex, and year on the basis of the Rhône-Alpes region population. Hospitalization and in-hospital mortality rates were compared using Chi(2) tests with statistical significance adjusted for multiple comparisons.

RESULTS

The highest hospitalization rates by age group were: all-cause pneumonia, oldest group (>65 years); all-cause and pneumococcal meningitis, youngest group (0-4 years), and pneumococcal pneumonia, youngest and oldest groups. Hospitalization rates significantly decreased for all-cause pneumonia (5-19 years: -12.71%) and all-cause meningitis (20-49 years: -29.22%). Pneumococcal disease rates did not significantly change in any age group. Mortality rates from all-cause pneumonia and meningitis were highest in the oldest age groups.

CONCLUSIONS

The burden of all-cause and pneumococcal pneumonia and meningitis remains substantial. Significant changes (decreases) between 2005 and 2010 in hospitalization rates were limited and varied among age groups, most likely because this study began 2 years after PCV7 was first introduced in France for children at broadly-defined high risk. Further research is needed on the relationship between serotype epidemiology and clinical patterns of disease.

The burden of bacteremia and invasive diseases in children aged less than five years with fever in Italy

Background

Invasive diseases (ID) caused by Streptococcus pneumoniae (S. pneumoniae), Haemophilus influenzae (H. influenzae), and Neisseria meningitidis are a major public health problem worldwide. Comprehensive data on the burden of bacteremia and ID in Italy, including data based on molecular techniques, are needed.

Methods

We conducted a prospective, multi-centre, hospital-based study (GSK study identifier: 111334) to assess the burden of bacteremia and ID among children less than five years old with a fever of 39 °C or greater. Study participation involved a single medical examination, collection of blood for polymerase chain reaction (PCR) and blood culture, and collection of an oropharyngeal swab for colonization analysis by PCR.

Results

Between May 2008 and June 2009, 4536 patients were screened, 944 were selected and 920 were enrolled in the study. There were 225 clinical diagnoses of ID, 9.8 % (22) of which were bacteremic. A diagnosis of sepsis was made for 38 cases, 5.3 % (2) of which were bacteremic. Among the 629 non-ID diagnoses, 1.6 % (10) were bacteremic. Among the 34 bacteremic cases, the most common diagnoses were community-acquired pneumonia (15/34), pleural effusion (4/34) and meningitis (4/34). S. pneumoniae was the most frequently detected bacteria among bacteremic cases (29/34) followed by H. influenzae (3/34). Ninety percent (27/30) of bacteremic patients with oropharyngeal swab results were colonized with the studied bacterial pathogens compared to 46.1 % (402/872) of non-bacteremic cases (p < 0.001). PCV7 (7-valent pneumococcal conjugate vaccine) vaccination was reported for 55.9 % (19/34) of bacteremic cases. S. pneumoniae serotypes were non-vaccine serotypes in children who had been vaccinated. Mean duration of hospitalization was longer for bacteremic cases versus non-bacteremic cases (13.6 versus 5.8 days).

Conclusions

These results confirm that S. pneumoniae is one of the pathogens frequently responsible for invasive disease.

Carriage of Streptococcus pneumoniae in asymptomatic, community-dwelling elderly in the Netherlands

Colonization of the upper respiratory tract by Streptococcus pneumoniae is considered prerequisite for pneumococcal disease. Despite high rates of pneumococcal disease in elderly, pneumococcal carriage rates are usually below 5% when detected by the conventional culture method. We assessed pneumococcal carriage in 330 asymptomatic community-dwelling elderly aged 65 years and older. While pneumococci were cultured from 25 (8%) individuals, 65 (20%) elderly were positive for the pneumococcus-specific lytA gene when tested by quantitative-PCR, increasing the overall number of carriers to 75 (22%). Significantly more oropharyngeal samples were pneumococci-positive (18% versus 10%, p<0.001) when tested by the molecular method as compared to nasopharyngeal samples. Our findings indicate that pneumococcal carriage in elderly is higher than previously reported with up to 1 in 5 asymptomatic community-dwelling elderly positive for pneumococcal carriage, when detected by qPCR. The detection of pneumococci by conventional culture alone, greatly underestimates S. pneumoniae colonization in elderly.

A few years later. Update of the cost-effectiveness of infant pneumococcal vaccination in Dutch children

This study aimed to calculate the cost-effectiveness of infant pneumococcal vaccination in the Netherlands, using the 13-valent PCV13 vs. the currently used 10-valent PCV10. We adapted a previously published model, using recent estimates of epidemiological and efficacy data. In 12 scenarios, we explored the impact of different assumptions on the incremental cost-effectiveness ratio (ICER) of PCV13 over PCV10.Taking only direct effects on invasive pneumococcal disease into account, PCV13 was not found to be cost-effective at a price difference of €11 per dose. If herd protection, replacement and non-invasive disease were also taken into account, the ICER of PCV13 compared with PCV10 was below €30 000/QALY gained in 11 of 12 scenarios. PCV13 was considered dominant in the primary scenario with a price difference below €2.63 per dose.

Effectiveness of 7-valent pneumococcal conjugate vaccine: A meta-analysis of post-marketing studies

AIM: To investigate the 7-valent pneumococcal conjugate vaccine (PCV7) effectiveness.

METHODS: A systematic literature review of studies which evaluated the effectiveness of PCV7 vaccine was performed searching the keyword “heptavalent pneumococcal conjugate vaccine” in PubMed and Scopus until March 16, 2013. The selection of potential eligible articles was done by two researchers independently on the basis of abstract and title and only post-marketing studies were included in the systematic review. Data extraction was carried out by two researchers with respect to invasive pneumococcal diseases due to both all and vaccine serotypes in pre-vaccine and post-vaccine periods in children less than 5 years. Results of studies which were considered suitable for meta-analysis were combined by means of relative risk (RR) with 95%CI. Vaccine effectiveness was calculated as (1-RR) × 100. Heterogeneity was assessed by I² and a random effects model was used to combine data in the case of heterogeneity. RevMan 5 was used to pool data.

RESULTS: On the whole, 757 eligible papers were identified from the literature search in PubMed and Scopus. Of them, 62 were finally considered in the systematic review and 38 were included in the meta-analysis. In all post-marketing studies included in the systematic review the incidence of invasive pneumococcal diseases due to vaccine serotypes declined significantly with the exception of few studies showing stability or a slight, but not significant, increase. Furthermore most of studies highlighted also a reduction in the incidence of invasive pneumococcal diseases due to all serotypes. With regards to meta-analysis, a random effects model was used to combine data because of the high heterogeneity. Data combination showed that the effectiveness of PCV7 in reducing invasive pneumococcal diseases due to vaccine serotypes and to all serotypes was 84% (95%CI: 74%-90%) and 53% (95%CI: 46%-59%) respectively. These results are confirmatory with respect to the efficacy of PCV7 against invasive pneumococcal diseases due to vaccine serotypes.

CONCLUSION: PCV7 implementation determines a significant decrease of invasive pneumococcal diseases.

Differential B-cell memory around the 11-month booster in children vaccinated with a 10- or 13-valent pneumococcal conjugate vaccine

Infants vaccinated with the 10- or 13-valent pneumococcal conjugate vaccine at 2, 3, 4, and 11 months had similar serotype-specific immunoglobulin G levels and plasma cell frequencies against 4 shared serotypes around these boosters, but higher memory B-cell frequencies in the PCV13 group.

Background. Both the 10- and 13-valent pneumococcal conjugate vaccines (PCV10 and PCV13) induce immunological memory against Streptococcus pneumoniae infections caused by vaccine serotypes. In addition to comparing serum antibody levels, we investigated frequencies of serotype-specific plasma cells (PCs) and memory B-cells (Bmems) as potential predictors of long-term immunity around the booster vaccination at 11 months of age.

Methods. Infants were immunized with PCV10 or PCV13 at 2, 3, 4, and 11 months of age. Blood was collected before the 11-month booster or 7–9 days afterward. Serotype-specific immunoglobulin G (IgG) levels were determined in serum samples by multiplex immunoassay. Circulating specific PCs and Bmems against shared serotypes 1, 6B, 7F, and 19F and against PCV13 serotypes 6A and 19A were measured in peripheral blood mononuclear cells by enzyme-linked immunospot assay.

Results. No major differences in IgG levels and PC frequencies between groups were found for the 4 shared serotypes. Notably, PCV13 vaccination resulted in higher frequencies of Bmems than PCV10 vaccination, both before and after the booster dose, for all 4 shared serotypes except for serotype 1 postbooster. For PCV13-specific serotypes 6A and 19A, the IgG levels and frequencies of PCs and Bmems were higher in the PCV13 group, pre- and postbooster, except for PC frequencies prebooster.

Conclusions. Both PCVs are immunogenic and induce measurable IgG, PC, and Bmem booster responses at 11 months. Compared to PCV10, vaccination with PCV13 was associated with overall similar IgG levels and PC frequencies but with higher Bmem frequencies before and after the 11-month booster. The clinical implications of these results need further follow-up.

Clinical Trials Registration. NTR3069.

Impact of 10-valent pneumococcal conjugate vaccine on pneumococcal meningitis in children up to two years of age in Brazil

The objective of this study was to analyze the impact of vaccination against Streptococcus pneumoniae on the morbidity and mortality from pneumococcal meningitis in children ≤ 2 years in Brazil, from 2007 to 2012. This is a descriptive study and ecological analysis using data from the Information System on Notifiable Diseases. Pre-vaccination (2007-2009) and post-vaccination (2011-2012) periods were defined to compare incidence rates and mortality. A total of 1,311 cases and 430 deaths were reported during the study period. Incidence decreased from 3.70/100,000 in 2007 to 1.84/100,000 in 2012, and mortality decreased from 1.30/100,000 to 0.40/100,000, or 50% and 69% respectively, with the greatest impact in the 6-11 month age group. This decrease in Pneumococcal meningitis morbidity and mortality rates two years after introduction of the 10-valent pneumococcal conjugate vaccine suggests its effectiveness.

A longitudinal study of streptococcus pneumoniae carriage in healthy children in the 13-valent pneumococcal conjugate vaccine era

Few epidemiological data are available after the introduction of the 13-valent pneumococcal vaccine (PCV13) in 2010. We performed repeat nasopharyngeal swabs and evaluated the serotype distribution of Streptococcus pneumoniae (SP) and its association with PCV13 vaccine status in healthy Italian children aged 3-59 months. SP serotypes were assessed by the Quellung reaction. 618 children appropriately (28%) or incompletely (72%) vaccinated for age with PCV13 were available at baseline (T0). 515 were re-evaluated at 6 months from baseline (T6) and 436 at 12 months from baseline (T12). The percentage of appropriately vaccinated subjects at T0, T6 and T12 was 28%, 67% and 92%, respectively. Random effects logistic regression models with robust 95% confidence intervals was used to estimate the time-related changes in SP and PCV13 carriage and marginal probabilities were obtained from such models. The age-corrected probability of SP carriage was 0.31 (95% CI 0.22 - 0.41) at T0, 0.32 (0.24 - 0.40) at T6 and 0.28 (0.20 - 0.35) at T12. The probability of PCV13 serotypes carriage was 0.025 (0.001 - 0.050) at T0, 0.018 (0.001 - 0.039) at T6 and 0.010 (0.001 - 0.023) at T12. A decrease in PCV13 serotypes and a shift in non-PCV13 serotypes colonization was observed. In particular, the 15A serotype accounted for 4%, 8% and 23% of SP isolates at T0, T6 and T12, respectively. In conclusion, the benefits of the PCV13 vaccination on SP carriage increase with increasing coverage rates. The shift of SP isolates toward non-PCV13 serotypes needs to be studied further.

Did introduction of pneumococcal vaccines in the Netherlands decrease the need for respiratory antibiotics in children? Analysis of 2002 to 2013 data

To estimate the effect of the introduction of the 7- and 10-valentpneumococcal vaccines in 2006 and 2011, respectively in the Netherlands, we assessed respiratory antibiotic use in one to nine year-old children between 2002 and 2013. Seasonal autoregressive integrated moving-average models were applied to estimate the percentage reduction in respiratory antibiotic use. When compared with the pre-vaccination period, the proportion of respiratory antibiotic prescriptions fell by 4.94% (95% CI: 4.63 to 5.26) and 9.02% (95% CI: 2.83 to 14.82) after the introduction of the 7-valent vaccine in children aged three and four years, respectively. After the introduction of the 10-valent vaccine, we observed a reduction of 13.04% (95% CI: 2.76 to 22.23), 20.31% (95% CI: 13.50 to 26.58), 16.92% (95% CI: 3.07 to 28.80), 22.34% (95% CI: 3.73 to 37.35), 23.75% (95% CI: 2.37 to 40.44) in two, three, four, six and seven year-old children, respectively. Thus, our results indicate a reduction in respiratory antibiotic prescriptions in young children after introduction of the pneumococcal vaccines. As only children in our study population aged one and two years born after March 2011 had received the 10-valent vaccine, the effects of the 10-valent vaccine in children aged three to nine years likely reflect the effects of the 7-valent vaccine and herd immunity.

Serotypes and genotypes of invasive Streptococcus pneumoniae before and after PCV10 implementation in southern Brazil

To reduce the burden of pneumococcal diseases, different formulations of pneumococcal conjugate vaccines (PCV) have been introduced in many countries. In Brazil, PCV10 has been available since 2010. We aimed to analyze the serotype and genetic composition of invasive pneumococci from Brazil in pre- and post- vaccination periods (2007–2012). Antibiotic susceptibility was determined and genotypes of macrolide and fluoroquinolone resistance were characterized. The genotypes of isolates of the most frequent serotypes were determined by multilocus sequence typing. The study included 325 isolates, which were primarily recovered from blood. The most common serotypes recovered were 14, 3, 4, 23F, 7F, 9V, 12F, 20, 19F, 8, 19A, and 5. Thirty-eight pneumococci (11.7%) were from children ≤5 years old. Considering the overall population, PCV10 and PCV13 serotype coverage was 50.1% and 64.9%, respectively. During the pre-vaccine period, isolates with serotypes belonging to the PVC10 represented 51.5% (100/194), whereas in the post vaccine they represented 48.0% (63/131). PCV13 serotypes represented 67.5% (131/194) and 59.2% (77/131) of total for pre- and post-vaccination periods, respectively. Seventy different sequence types [STs] were found, accounting for 9 clonal complexes [CCs] and 45 singletons. Eight STs (156, 180, 218, 8889, 53, 191, 770, and 4967) represented the majority (51.5%) of isolates. Fifty STs were associated with the pre-vaccination period (27 exclusive) and 43 (20 exclusive) with the post-vaccination period; 23 STs were identified in both periods. Some serotypes were particularly clonal (7F, 8, 12F, 20). Non-susceptibility to penicillin was associated with serotype 19A, CC320. Erythromycin resistance was heterogeneous when considering serotype and ST. A single serotype 23F (ST4967) isolate was resistant to levofloxacin. Continued surveillance is required to determine vaccine impact and to monitor changes in pneumococcal population biology post-PCV10 introduction in Brazil.

Clinical manifestations of invasive pneumococcal disease by vaccine and non-vaccine types

Pneumococcal conjugated vaccines (PCVs) have shown protection against invasive pneumococcal disease by vaccine serotypes, but an increase in non-vaccine serotype disease has been observed. Type-specific effects on clinical manifestation need to be explored. Clinical data from 2096 adults and 192 children with invasive pneumococcal disease were correlated to pneumococcal molecular serotypes. Invasive disease potential for pneumococcal serotypes were calculated using 165 invasive and 550 carriage isolates from children. The invasive disease potential was lower for non-PCV13 compared to vaccine-type strains. Patients infected with non-PCV13 strains had more underlying diseases, were less likely to have pneumonia and, in adults, tended to have a higher mortality. Furthermore, patients infected with pneumococci belonging to clonal serotypes only expressing non-PCV13 capsules had a higher risk for septicaemia and mortality. PCV vaccination will probably lead to a decrease in invasive pneumococcal disease but an alteration in the clinical manifestation of invasive pneumococcal disease. Genetic lineages causing invasive pneumococcal disease in adults often express non-vaccine serotypes, which can expand after vaccination with an increased risk of infection in patients with underlying diseases.

IgG levels against 13-valent pneumococcal conjugate vaccine serotypes in non pneumococcal conjugate vaccine immunized healthy Japanese and intravenous immunoglobulin preparations

No studies showed specific antibody levels against all serotypes covered by 13-valent pneumococcal conjugate vaccine (PCV13) among polyclonal intravenous immunoglobulin (IVIG) products. Our study aimed to assess whether we could expect the efficacy of IVIG therapy for invasive pneumococcal disease (IPD) and to clarify the age group which should be recommended for IVIG therapy in case of IPD. Serotype-specific immunoglobulin G (IgG) levels against PCV13 serotypes were measured in four IVIGs which were produced from Japanese donors who were not immunized with any pneumococcal conjugate vaccines (PCVs), and in the serum of 160 non-PCV immunized Japanese subjects, by enzyme-linked immunosorbent assay. The functional opsonic activities of the IVIGs against serotypes 6B and 19A were assessed by a multiplexed opsonophagocytic killing assay. Japanese infants aged <2 years had a geometric mean IgG concentration of <0.35 μg/ml against several serotypes. Serotype-specific IgG concentrations varied among IVIGs. In general, IgG antibodies against serotypes 6A, 14 and 19A were higher in each IVIG. Although opsonization indices also varied among preparations, each IVIG had the ability to opsonize both serotypes 6B and 19A. This study suggests that routine immunization with PCV is important for prevention of IPD, especially for children <2 years old and IVIGs might be effective for IPD patients.

Serotype epidemiology of invasive pneumococcal disease in Swiss adults: a nationwide population-based study

BACKGROUND

In Switzerland, the heptavalent (PCV7) and 13-valent pneumococcal conjugate vaccine (PCV13) were recommended for all infants aged <2 years in 2007 and 2011, respectively. Due to herd effects, a protective impact on the invasive pneumococcal disease (IPD) rates in adults had been expected.

METHODS

Within this study, data from the nationwide mandatory surveillance was analyzed for all adult patients ≥16 years with IPD of known serotype/serogroup during 2003-2012. Trend (for IPD cases from 2003 to 2012) and logistic regression analyses (2007-2010) were performed to identify changes in serotype distribution and to identify the association of serotypes with age, clinical manifestations, comorbidities and case fatality, respectively.

FINDINGS

The proportion of PCV7 serotypes among all IPD cases (n=7678) significantly declined in adults from 44.7% (2003) before to 16.7% (2012) after the recommendation of PCV7 (P<0.001). In contrast, the proportion of non-PCV7 serogroup/serotypes increased for non-PCV13 but also PCV13 serotypes (not included in PCV7) at the same time. Serotype distribution varied significantly across ages, clinical manifestations and comorbidities. Serotype was furthermore associated with case fatality (P=0.001). In a multivariable logistic regression model, analyzing single serotypes showed that case-fatality was increased for the serotypes 3 (P=0.008), 19A (P=0.03) and 19F (P=0.005), compared to serotype 1 and 7F.

CONCLUSION

There was a significant decline in PCV7 serotypes among adults with IPD in Switzerland after introduction of childhood vaccination with PCV7. Pneumococcal serotypes were associated with case fatality, age, clinical manifestation and comorbidities of IPD in adults. These results may prove useful for future vaccine recommendations for adults in Switzerland.