The worldwide impact of the seven-valent pneumococcal conjugate vaccine

Using Standardized Interpretation of Chest Radiographs to Identify Adults with Bacterial Pneumonia--Guatemala, 2007-2012

Background

Bacterial pneumonia is a leading cause of illness and death worldwide, but quantifying its burden is difficult due to insensitive diagnostics. Although World Health Organization (WHO) protocol standardizes pediatric chest radiograph (CXR) interpretation for epidemiologic studies of bacterial pneumonia, its validity in adults is unknown.

Methods

Patients (age ≥15 years) admitted with respiratory infections to two Guatemalan hospitals between November 2007 and March 2012 had urine and nasopharyngeal/oropharyngeal (NP/OP) swabs collected; blood cultures and CXR were also performed at physician clinical discretion. ‘Any bacterial infection’ was defined as a positive urine pneumococcal antigen test, isolation of a bacterial pneumonia pathogen from blood culture, or detection of an atypical bacterial pathogen by polymerase chain reaction (PCR) of nasopharyngeal/oropharyngeal (NP/OP) specimens. ‘Viral infection’ was defined as detection of viral pathogens by PCR of NP/OP specimens. CXRs were interpreted according to the WHO protocol as having ‘endpoint consolidation’, ‘other infiltrate’, or ‘normal’ findings. We examined associations between bacterial and viral infections and endpoint consolidation.

Findings

Urine antigen and/or blood culture results were available for 721 patients with CXR interpretations; of these, 385 (53%) had endpoint consolidation and 253 (35%) had other infiltrate. Any bacterial infection was detected in 119 (17%) patients, including 106 (89%) pneumococcal infections. Any bacterial infection (Diagnostic Odds Ratio [DOR] = 2.9; 95% confidence Interval (CI): 1.3–7.9) and pneumococcal infection (DOR = 3.4; 95% CI: 1.5–10.0) were associated with ‘endpoint consolidation’, but not ‘other infiltrate’ (DOR = 1.7; 95% CI: 0.7–4.9, and 1.7; 95% CI: 0.7–4.9 respectively). Viral infection was not significantly associated with ‘endpoint consolidation’, ‘other infiltrate,’ or ‘normal’ findings.

Interpretation

‘Endpoint consolidation’ was associated with ‘any bacterial infection,’ specifically pneumococcal infection. Therefore, endpoint consolidation may be a useful surrogate for studies measuring the impact of interventions, such as conjugate vaccines, against bacterial pneumonia.

Dissecting the indirect effects caused by vaccines into the basic elements

Vaccination directly protects vaccinated individuals, but it also has the potential for indirectly protecting the unvaccinated in a population (herd protection). Unintended negative consequences such as the re-manifestation of infection, mainly expressed as age shifts, result from vaccination programs as well. We discuss the necessary conditions for achieving optimal herd protection (i.e., high quality vaccine-induced immunity, substantial effect on the force of infection, and appropriate vaccine coverage and distribution), as well as the conditions under which age shifts are likely to occur. We show examples to illustrate these effects. Substantial ambiguity in observing and quantifying these indirect vaccine effects makes accurate evaluation troublesome even though the nature of these outcomes may be critical for accurate assessment of the economic value when decision makers are evaluating a novel vaccine for introduction into a particular region or population group. More investigation is needed to identify and develop successful assessment methodologies for precisely analyzing these outcomes.

Genetic Stabilization of the Drug-Resistant PMEN1 Pneumococcus Lineage by Its Distinctive DpnIII Restriction-Modification System

The human pathogen Streptococcus pneumoniae (pneumococcus) exhibits a high degree of genomic diversity and plasticity. Isolates with high genomic similarity are grouped into lineages that undergo homologous recombination at variable rates. PMEN1 is a pandemic, multidrug-resistant lineage. Heterologous gene exchange between PMEN1 and non-PMEN1 isolates is directional, with extensive gene transfer from PMEN1 strains and only modest transfer into PMEN1 strains. Restriction-modification (R-M) systems can restrict horizontal gene transfer, yet most pneumococcal strains code for either the DpnI or DpnII R-M system and neither limits homologous recombination. Our comparative genomic analysis revealed that PMEN1 isolates code for DpnIII, a third R-M system syntenic to the other Dpn systems. Characterization of DpnIII demonstrated that the endonuclease cleaves unmethylated double-stranded DNA at the tetramer sequence 5′ GATC 3′, and the cognate methylase is a C5 cytosine-specific DNA methylase. We show that DpnIII decreases the frequency of recombination under in vitro conditions, such that the number of transformants is lower for strains transformed with unmethylated DNA than in those transformed with cognately methylated DNA. Furthermore, we have identified two PMEN1 isolates where the DpnIII endonuclease is disrupted, and phylogenetic work by Croucher and colleagues suggests that these strains have accumulated genomic differences at a higher rate than other PMEN1 strains. We propose that the R-M locus is a major determinant of genetic acquisition; the resident R-M system governs the extent of genome plasticity.

Pneumococcus is one of the most important community-acquired bacterial pathogens. Pneumococcal strains can develop resistance to antibiotics and to serotype vaccines by acquiring genes from other strains or species. Thus, genomic plasticity is associated with strain adaptability and pneumococcal success. PMEN1 is a widespread and multidrug-resistant highly pathogenic pneumococcal lineage, which has evolved over the past century and displays a relatively stable genome. In this study, we characterize DpnIII, a restriction-modification (R-M) system that limits recombination. DpnIII is encountered in the PMEN1 lineage, where it replaces other R-M systems that do not decrease plasticity. Our hypothesis is that this genomic region, where different pneumococcal lineages code for variable R-M systems, plays a role in the fine-tuning of the extent of genomic plasticity. It is possible that well-adapted lineages such as PMEN1 have a mechanism to increase genomic stability, rather than foster genomic plasticity.

Association of pneumococcal conjugate vaccination with rates of ventilation tube insertion in Denmark: population-based register study

OBJECTIVE

To examine if the introduction of pneumococcal conjugate vaccine (PCV) in Denmark was associated with a decrease in the rate of ventilation tube (VT) insertions performed by office-based practising ear, nose and throat (ENT) specialists.

DESIGN

Population-based register study based on prospectively collected data.

SETTING

Central Denmark Region. Data on VT insertions performed by any office-based practising ENT specialist in the region were collected from the National Health Service Registry.

PARTICIPANTS

All children below the age of 2 years with a first-time VT insertion from 2001 through 2011.

MAIN OUTCOME MEASURES

Age-stratified and gender-stratified standardised incidence rates of first-time VT insertion, and incidence rate ratio for PCV period 2008-2011 compared with pre-PCV period 2001-2007.

RESULTS

The annual incidence rate of first-time VT insertion in small children increased steadily from 64/1000 person-years in 2001 to 100/1000 person-years in 2011. The incidence rate ratio was 1.27 (95% CI 1.24 to 1.30) in the PCV period compared with the pre-PCV period.

CONCLUSIONS

The introduction of PCV into the Danish childhood immunisation programme in 2007 was not associated with a subsequent decrease in the rate of VT insertions among children below the age of 2 years. Instead, the rate continued to rise, as before the introduction of PCV.

TRIAL REGISTRATION NUMBER

Danish Data Protection Agency: 2007-58-0010.

Host-pathogen interaction during bacterial vaccination

Vaccines have been developed and deployed against several important bacterial pathogens of humans, including Neisseria meningitidis, Bordetella pertussis, Streptococcus pneumoniae and Mycobacterium tuberculosis. These vaccines are generally considered a successful public health measure and are effective at controlling disease symptoms and/or burden. However, a troubling consequence of recent vaccination programs has been the selection of vaccine escape mutants, whereby the pathogen displays a different repertoire of immune targets than those represented in the vaccine formulation. To address these issues of antigenic variation and bacterial evolution, continued and sustained efforts in epidemiological surveillance, vaccine development/formulation research, and understanding of the host-pathogen interaction are required.

Genomics Reveals the Worldwide Distribution of Multidrug-Resistant Serotype 6E Pneumococci

The pneumococcus is a leading pathogen infecting children and adults. Safe, effective vaccines exist, and they work by inducing antibodies to the polysaccharide capsule (unique for each serotype) that surrounds the cell; however, current vaccines are limited by the fact that only a few of the nearly 100 antigenically distinct serotypes are included in the formulations. Within the serotypes, serogroup 6 pneumococci are a frequent cause of serious disease and common colonizers of the nasopharynx in children. Serotype 6E was first reported in 2004 but was thought to be rare; however, we and others have detected serotype 6E among recent pneumococcal collections. Therefore, we analyzed a diverse data set of ∼1,000 serogroup 6 genomes, assessed the prevalence and distribution of serotype 6E, analyzed the genetic diversity among serogroup 6 pneumococci, and investigated whether pneumococcal conjugate vaccine-induced serotype 6A and 6B antibodies mediate the killing of serotype 6E pneumococci. We found that 43% of all genomes were of serotype 6E, and they were recovered worldwide from healthy children and patients of all ages with pneumococcal disease. Four genetic lineages, three of which were multidrug resistant, described ∼90% of the serotype 6E pneumococci. Serological assays demonstrated that vaccine-induced serotype 6B antibodies were able to elicit killing of serotype 6E pneumococci. We also revealed three major genetic clusters of serotype 6A capsular sequences, discovered a new hybrid 6C/6E serotype, and identified 44 examples of serotype switching. Therefore, while vaccines appear to offer protection against serotype 6E, genetic variants may reduce vaccine efficacy in the longer term because of the emergence of serotypes that can evade vaccine-induced immunity.

Protection against Streptococcus pneumoniae lung infection after nasopharyngeal colonization requires both humoral and cellular immune responses

Streptococcus pneumoniae is a common cause of pneumonia and infective exacerbations of chronic lung disease, yet there are few data on how adaptive immunity can specifically prevent S. pneumoniae lung infection. We have used a murine model of nasopharyngeal colonization by the serotype 19F S. pneumoniae strain EF3030 followed by lung infection to investigate whether colonization protects against subsequent lung infection and the mechanisms involved. EF3030 colonization induced systemic and local immunoglobulin G against a limited number of S. pneumoniae protein antigens rather than capsular polysaccharide. During lung infection, previously colonized mice had increased early cytokine responses and neutrophil recruitment and reduced bacterial colony-forming units in the lungs and bronchoalveolar lavage fluid compared with control mice. Colonization-induced protection was lost when experiments were repeated in B-cell- or neutrophil-deficient mice. Furthermore, the improved interleukin (IL)-17 response to infection in previously colonized mice was abolished by depletion of CD4+ cells, and prior colonization did not protect against lung infection in mice depleted of CD4+ cells or IL17. Together these data show that naturally acquired protective immunity to S. pneumoniae lung infection requires both humoral and cell-mediated immune responses, providing a template for the design of improved vaccines that can specifically prevent pneumonia or acute bronchitis.

Impact of pneumococcal conjugate vaccine on pediatric tympanostomy tube insertion in partial immunized population

Objective. To investigate the impact of seven-valent pneumococcal conjugate vaccine on tube insertions in a partial immunized pediatric population. Study Design. Retrospective ecological study. Methods. This study used Taiwan National Health Insurance Research Database for the period 2000–2009. Every child under 17 years old who received tubes during this 10-year period was identified and analyzed. The tube insertion rates in different age groups and the risk to receive tubes in different birth cohorts before and after the release of the vaccine in 2005 were compared. Results. The tube insertion rates for children under 17 years of age ranged from 21.6 to 31.9 for 100,000 persons/year. The tube insertion rate of children under 2 years old decreased significantly after 2005 in period effect analysis (β = −0.074, P < 0.05, and the negative β value means a downward trend) and increased in children 2 to 9 years old throughout the study period (positive β values which mean upward trends, P < 0.05). The rate of tube insertion was lower in 2004-2005 and 2006-2007 birth cohorts than that of 2002-2003 birth cohort (RR = 0.90 and 0.21, 95% CI 0.83–0.97 and 0.19–0.23, resp.). Conclusion. The seven-valent pneumococcal conjugate vaccine may reduce the risk of tube insertion for children of later birth cohorts. The vaccine may have the protective effect on tube insertions in a partial immunized pediatric population.

Pneumococcal meningitis: epidemiological profile pre- and post-introduction of the pneumococcal 10-valent conjugate vaccine

OBJECTIVES

To evaluate the possible effects of the introduction of the pneumococcal conjugate 10-valent vaccine schedule in the state of Parana on pneumococcal meningitis cases and to assess the distribution of serotypes among cases.

METHOD

Cross-sectional study with retrospective data collection of cases of pneumococcal meningitis in the state of Paraná reported to Sistema de Informação de Agravos de Notificação (SINAN), from 1998 to 2011. A total of 1,339 cases of pneumococcal meningitis were analyzed; 1,205 cases from the pre-vaccine period (1998-2009) were compared to 134 cases from the post-vaccine period (2010-2011). Descriptive and comparative statistical analyses (chi-squared test and prevalence ratio) were performed using JMP 5.1.2 statistical software (JMP Statistical Discovery, North Carolina, USA) and EPI INFO 6 (Centers for Disease Control and Prevention, Georgia, EUA).

RESULTS

There was a significant reduction in the mean rates of incidence and mortality in the general population. The analysis of cases in the pre- and post-vaccination periods in the age groups covered by vaccination (younger than 2 years) showed significant reductions in incidence rates (6.01 cases/100,000 to 2.49 cases/100,000 individuals) and mortality (1.85 cases/100,000 population to 0.47 cases/100,000 population), while the mean lethality rate did not change significantly. There was a significant reduction in cases whose serotypes are included in the vaccine (80.7% to 53.3%).

CONCLUSION

Even after a short time of use, the 10-valent pneumococcal conjugate vaccine has already had a significant impact in reducing the incidence and mortality of meningitis cases among infants, as well as the reduction of cases whose serotypes are included in the vaccine.

Changing trends of acute otitis media bacteriology in central Israel in the pneumococcal conjugate vaccines era

BACKGROUND

The widespread use of 7-valent pneumococcal conjugate vaccine (PCV7) has changed acute otitis media (AOM) bacteriology. Only scattered data with regard to this effect of PCV13 have been published so far.

METHODS

We retrospectively identified children <6 years of age who presented to our hospital with AOM, and had middle ear fluid (MEF) cultures obtained during tympanocentesis or from spontaneous otorrhea during 2008-2013, when PCV7 (2009) and PCV13 (2010) were gradually introduced in the Israeli National Immunization Program. Data were extracted for demographics, clinical and microbiologic parameters, according to vaccination status.

RESULTS

Of the 295 eligible AOM episodes reported in 279 children, 224 (76%) had MEF cultures from tympanocentesis and 71 (24%) from spontaneous otorrhea. Boys and children <2 years of age contributed 178 (60%) and 219 (74%) AOM episodes, respectively. Acute mastoiditis complicated 58 (20%) of these episodes. None of the children were PCV immunized in 2008, but >90% had received ≥1 PCV dose(s) by 2011 or later. Of the 106 (36%) MEF cultures which tested positive for otopathogens, Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis and multiple bacteria grew in 60 (57%), 39 (37%), 2 (2%) and 5 (5%) episodes, respectively. S. pneumonia-positive MEF culture rate in unimmunized children (31, 69%) was significantly higher than in PCV7-immunized children (22, 59%) or PCV13-immunized children (12, 50%), P = 0.04 and P = 0.02, respectively.

CONCLUSION

PCV7 and PCV13 implementations in the Israeli National Immunization Program were associated with a rapid reduction of "severe" pneumococcal AOM episodes.

Clinical vaccine development

Vaccination is regarded as one of the biggest triumphs in the history of medicine. We are living in the most successful period of vaccine development. The accumulation of multidisciplinary knowledge and the investment of massive funding have enabled the development of vaccines against many infectious diseases as well as other diseases including malignant tumors. The paradigm of clinical vaccine evaluation and licensure has also been modernized based on scientific improvements and historical experience. However, there remain a number of hurdles to overcome. Continuous efforts are focused on increasing the efficacy and reducing the risks related to vaccine use. Cutting-edge knowledge about immunology and microbiology is being rapidly translated to vaccine development. Thus, physicians and others involved in the clinical development of vaccines should have sufficient understanding of the recent developmental trends in vaccination and the diseases of interest.

Cost-Effectiveness Evaluation of the 10-Valent Pneumococcal Non-typeable Haemophilus influenzae Protein D Conjugate Vaccine and 13-Valent Pneumococcal Vaccine in Japanese Children

INTRODUCTION

Diseases caused by Streptococcus pneumoniae represent a major public health problem. The purpose of this study was to compare, in the Japanese context, the projected health benefits, costs and cost-effectiveness of the latest generation of pneumococcal conjugate vaccines which may provide important insight into the potential public health impact of interventions in the context of local disease-specific epidemiology.

METHODS

A Markov model was used to compare two vaccination strategies which involve routine infant immunization with either the 13-valent pneumococcal conjugate vaccine (PCV-13; Prevenar 13™, Pfizer, Pearl River, NY, USA) or the 10-valent pneumococcal non-typeable Haemophilus influenzae protein D conjugate vaccine (PHiD-CV; Synflorix™, GlaxoSmithKline Biologicals SA, Rixensart, Belgium) over a time horizon of 5 years from the healthcare provider and societal perspectives. Estimates for key model parameters were obtained from locally available databases and published literature. Incremental benefits in terms of costs and quality-adjusted life-year and cost-effectiveness were assessed.

RESULTS

A 3 + 1 vaccination schedule for infants with PHiD-CV is expected to have a similar impact on invasive pneumococcal disease and pneumonia and a larger impact on acute otitis media-related outcomes compared with PCV-13. Assuming price parity for these vaccines, the model projected that vaccination with PHiD-CV would result in cost savings of 1.9 and 3.9 billion Japanese yen from the provider and societal perspectives, respectively. This was largely due to a reduction in highly prevalent acute otitis media. Vaccination with PHiD-CV was expected to generate a gain of 433 quality-adjusted life-years compared to PCV-13 translating into dominance over PCV-13. Sensitivity analyses showed robustness of model outcome to changes in key model parameters and substantiated that the model outcome was consistently driven by the incremental benefit of PHiD-CV in averting acute otitis media.

CONCLUSION

In comparison to PCV-13, vaccination with PHiD-CV is projected to be cost saving for Japan from both the healthcare provider and societal perspectives.

Sinusitis and pneumonia hospitalization after introduction of pneumococcal conjugate vaccine

BACKGROUND AND OBJECTIVE

Streptococcus pneumoniae is a major cause of pneumonia and sinusitis. Pneumonia kills >1 million children annually, and sinusitis is a potentially serious pediatric disease that increases the risk of orbital and intracranial complications. Although pneumococcal conjugate vaccine (PCV) is effective against invasive pneumococcal disease, its effectiveness against pneumonia is less consistent, and its effect on sinusitis is not known. We compared hospitalization rates due to sinusitis, pneumonia, and empyema before and after sequential introduction of PCV7 and PCV13.

METHOD

All children 0 to <18 years old hospitalized for sinusitis, pneumonia, or empyema in Stockholm County, Sweden, from 2003 to 2012 were included in a population-based study of hospital registry data on hospitalizations due to sinusitis, pneumonia, or empyema. Trend analysis, incidence rates, and rate ratios (RRs) were calculated comparing July 2003 to June 2007 with July 2008 to June 2012, excluding the year of PCV7 introduction.

RESULTS

Hospitalizations for sinusitis decreased significantly in children aged 0 to <2 years, from 70 to 24 cases per 100 000 population (RR = 0.34, P < .001). Hospitalizations for pneumonia decreased significantly in children aged 0 to <2 years, from 450 to 366 per 100 000 population (RR = 0.81, P < .001) and in those aged 2 to <5 years from 250 to 212 per 100 000 population (RR = 0.85, P = .002). Hospitalization for empyema increased nonsignificantly. Trend analyses showed increasing hospitalization for pneumonia in children 0 to <2 years before intervention and confirmed a decrease in hospitalizations for sinusitis and pneumonia in children aged 0 to <5 years after intervention.

CONCLUSIONS

PCV7 and PCV13 vaccination led to a 66% lower risk of hospitalization for sinusitis and 19% lower risk of hospitalization for pneumonia in children aged 0 to <2 years, in a comparison of 4 years before and 4 years after vaccine introduction.

All-cause pneumonia hospitalizations in children <2 years old in sweden, 1998 to 2012: impact of pneumococcal conjugate vaccine introduction

BACKGROUND

In late 2007, some Swedish County Councils started 7-valent pneumococcal conjugate vaccine (PCV7) implementation for children, and PCV7 was included in the national immunization program in 2009. By 2010, both PCV10 and PCV13 were licensed, and the selection of vaccine was subject to County Councils tenders. This study investigated the impact of the order of PCV introduction into vaccination programs on the incidence of all-cause pneumonia hospitalizations in children <2 years-old.

METHODS

Using population-based data from the publicly available National Inpatient Registry, the incidence of inpatient pneumonia (ICD-10 J12-J18) hospitalizations by County Councils among children <2 years old was identified between 1998 and 2012. Incidence rate ratios (IRR; 95% CI) were calculated during the nationwide implementation of PCV7 and then between County Councils, as based on the higher-valent vaccine chosen for a program.

RESULTS

There was a lower risk of all-cause pneumonia hospitalization among <2 year-old children following the introduction of PCV7, as compared to the pre-PCV7 period (0.77; 0.63-0.93). A decreased risk of all-cause pneumonia was also observed in the County Councils that followed the order PCV7 then PCV13 (0.82; 0.66-1.01), while no trend was observed in County Councils with a program in the order PCV7 then PCV10 (1.03; 0.82-1.30). When comparing the higher-valent vaccines, there was a 21% (0.79; 0.66-0.96) lower risk for childhood pneumonia hospitalization in County Councils finally using PCV13 as compared to the experience in County Councils that ultimately adopted PCV10.

CONCLUSIONS

Among children <2 years-old, all-cause pneumonia hospitalizations were significantly reduced by 23% one to two years after introduction of PCV7 vaccination in Sweden. In those County Councils that next introduced PCV13, a further decline in all-cause pneumonia hospitalization was observed, in contrast to those County Councils that followed with PCV10; this 21% lower risk for childhood pneumonia hospitalization was statistically significant.

Safety and tolerability of 13-valent pneumococcal conjugate vaccine in the elderly

BACKGROUND

In September 2011 the European Medical Agency authorized the use of 13-valent pneumococcal conjugate vaccine (PCV13) in adults aged ≥50 years. The same occurred in the US in December 2011 when the Food and Drug Administration approved the use of PCV13 in the same target age-group with indication for the prevention of invasive pneumococcal diseases and community acquired pneumonia sustained by the serotypes contained in the vaccine. The Liguria Region, in Italy, implemented in 2013 an active and free of charge immunization strategy with PCV13 among adults affected by specific risk conditions and the elderly aged ≥70 years.

METHODS

An observational study was performed in order to assess the safety and tolerability of PCV13 among elderly dwelling in the metropolitan area of Genoa, the capital city of Liguria Region. Eligible subjects, who received PCV13 following the public health immunization campaign at the Local Health Unit 3 of Genoa, provided a written informed consent to take part in the study. Eight-hundred-seventy-one subjects were enrolled between October 2013 and May 2014: all were monitored by qualified healthcare personnel for at least 30 min after vaccination at the outpatient clinics, in order to assess any possible sudden reaction. The occurrence of a series of local and systemic solicited reactions and of any unsolicited Adverse Events (AEs) was monitored using a self-administered clinical diary and by regular phone contacts up to 14 and 21 d following immunization, respectively. Moreover, a 6-months follow-up following vaccination was planned in order to monitor Severe Adverse Events (SAEs).

RESULTS

No sudden reaction occurred in vaccinees at the outpatient clinics. Pain (27.4%) was the most frequent reaction reported by subjects at the injection site, while new muscle pain (13.6%), fatigue (10.7%), and headache (9.9%) resulted the most common systemic reactions. Rates of the main reactions reported in this on-field study resulted generally lower than those registered in clinical trials performed in the elderly. The incidence of fever (2.2%) following vaccination was low at values superimposable to that reported in previous studies.

CONCLUSION

This observational study showed a good safety and tolerability of PCV13 among the elderly in routine clinical practice further confirming the evidence coming from clinical trials in the same age-group.

Adult vaccination

Vaccination of children has had a major impact on the morbidity and mortality of many infectious diseases globally. However, with age, immune responses to vaccines can be less robust, which can be further enhanced by underlying diseases that are common in the older adult. In many countries around the globe booster vaccinations against diphtheria, tetanus, and pertussis are recommended for adults. For the older adult, vaccination against pneumococcal diseases, influenza and herpes zoster are also recommended. Despite these recommendations, the widespread use of these vaccines in the adult population clearly lags behind the vaccine uptake and successes documented for pediatric vaccination programs. Furthermore, extensive and sometimes inappropriate use of antibiotics have fostered the emergence of antibiotic-resistant bacteria (e.g., methicillin resistant Staphylococcus aureus (MRSA)) as well as increased susceptibility in the elderly to bacterial species such as Clostridium difficile. Infectious diseases remain an important unmet medical need and new concepts to successfully implement vaccination of adults are urgently needed.

Recommendations for pneumococcal immunization outside routine childhood immunization programs in Western Europe

The global burden of pneumococcal diseases is high, with young children and adults ≥50 years of age at highest risk of infection. Two types of vaccine are available for the prevention of pneumococcal diseases caused by specific Streptococcus pneumoniae serotypes: the pneumococcal polysaccharide vaccine (PPV23) and the pneumococcal conjugate vaccine (PCV7, PCV10, and PCV13). Despite pneumococcal immunization programs in adults and children, the burden in adults has remained high. Most European countries have national or local/regional vaccination recommendations. The objective of this review was to provide an overview of the government recommendations for pneumococcal vaccination outside routine childhood vaccination programs for 16 Western European countries as of August 2014. We found that recommendations for pneumococcal immunization across Europe are complex and vary greatly among countries in terms of age groups and risk groups recommended for vaccination, as well as which vaccine should be administered. Clarifying or simplifying these recommendations and improving their dissemination could help to increase pneumococcal vaccine uptake and decrease the high burden of pneumococcal diseases in adults, both through a direct effect of the vaccine and via a herd effect in unvaccinated individuals.

Predicting the impact of new pneumococcal conjugate vaccines: serotype composition is not enough

Streptococcus pneumoniae is a major cause of childhood morbidity and mortality worldwide. A heptavalent polysaccharide-protein conjugate vaccine (PCV) has proven highly effective in preventing pneumococcal disease in industrialized countries. Two higher-valent pneumococcal conjugate vaccines are now widely available, even in the poorest countries. These differ from each other in the number of serotypes and carrier proteins used for their conjugation. Some have assumed that the only meaningful clinical difference between PCV formulations is a function of the number of serotypes each contains. A careful review of recent clinical data with these and several unlicensed PCV formulations points to important similarities but also that some key properties of each vaccine likely differ from one another.

Evolving role of 13-valent pneumococcal conjugate vaccine in clinical practice

Since the introduction of 7-valent pneumococcal conjugate vaccine (PCV7), PCVs with extended coverage have become available, and there is emerging global evidence that these vaccines, in particular PCV13, have further reduced rates of invasive pneumococcal disease compared with PCV7. The present article aims to address emerging topics related to PCV13 use in routine clinical practice; specifically: (1) the potential role of high-valent PCVs in reducing pneumococcal disease burden; (2) the impact of PCVs on nasopharyngeal carriage and how this may contribute to reductions in otitis media and pneumonia, as well as the prevalence of resistant pneumococcal strains; (3) new PCV13 indications and (4) importance of schedule adherence for PCV in the prevention of cases of vaccine serotype-specific invasive pneumococcal disease. The beneficial effects of PCVs in protecting individuals from a wide spectrum of pneumococcal diseases can be increased by improving the vaccine coverage and adhering to the recommended vaccination schedules. There is increasing evidence that PCV13 has reduced much of the post-PCV7 burden of pneumococcal diseases in the pediatric community, including reducing pneumococcal colonization and the incidence of invasive pneumococcal disease and mucosal diseases. This has also led to a reduction in antibiotic-resistant pneumococcal diseases. The role of PCV13 in clinical practice is evolving, with PCV13 now available for children and adolescents between the ages of 6 weeks and 17 years, thus ensuring that children in all age groups can be protected against vaccine-serotype pneumococcal diseases. Continued surveillance is warranted to monitor the impact of PCV13 on disease burden.

[Epidemiological study of nasopharyngeal carriers of Streptococcus pneumoniae in children in Murcia region]

BACKGROUND AND OBJECTIVES

Streptococcus pneumoniae is a human pathogen that requires prior nasopharyngeal colonization to cause disease. An epidemiological study was conducted on nasopharyngeal carriers of pneumococci in healthy children in Murcia after the introduction of the VCN7, and immediately before the marketing of new vaccines, with the aim of determining the influence of vaccination in our geographic area, and other factors in relation to the state of being a carrier, and the different circulating serotypes.

METHODS

A multicentre study was conducted in in 60 primary care health centres in summer 2009 and winter of 2010. A nasopharyngeal swab was collected, and an epidemiological study was carried out on 1562 children aged 1 and 4 years. Of the 1562 nasopharyngeal samples, pneumococci were found in 489 of them, with 343 of them able to be serotyped (70.2%).

RESULTS

The prevalence of carriers was 31.3%. Of the patients included, 61.7% (964/1562) had received at least one dose of VCN7. Only 12.8% of the identified serotypes were vaccine serotypes. The independent protective factors against colonization were; Summer time in all age groups, previous vaccination in all the children (OR: 0.75; 95%CI: 0.56-0.93]; P=.01, and in 1-year-olds (OR: 0.6; 95%CI: 0.42-0.84; P=.002), and had taken antibiotics in the last month in the total cohort [OR: 0.69; 95%CI: 0.50-0.96). On the other hand, attendance at school or day-care centre (OR: 1.85; 95%CI: 1.27-2.18; P=.001), number of siblings (OR: 1.3; 95%CI: 1.01-1.91), and passive tobacco smoke exposure (OR: 1.33; 95%CI: 1.02-1.73), were colonization risk factors. The serotypes 6A, 19A, 23B, 15A/B, 11A, 14, 23A/F, 3 y 19F were the most prevalent.

CONCLUSIONS

A low proportion of SV was found, with 14, 23F and 19F are persisting. A high prevalence of serotypes 6A and 19A was found. Summer time, vaccination, and the prior administration of antibiotics proved to be protective against colonization, whereas schooling, smoking, and siblings contributed to it.

Impact of 10-valent pneumococcal non-typeable Haemophilus influenzae protein D conjugate vaccine (PHiD-CV) on childhood pneumonia hospitalizations in Brazil two years after introduction

INTRODUCTION

Pneumococcal disease is a major public health problem worldwide. From March to September of 2010, 10-valent pneumococcal non-typeable Haemophilus influenzae protein conjugate vaccine (PHiD-CV) was introduced in the Brazilian childhood National Immunization Program (NIP) in all 27 Brazilian states. The aim of the present study is to report national time-trends in incidence of hospital admissions for childhood pneumonia in Brazil before and after two years of introduction of this new pneumococcal conjugate vaccine.

METHODS

Analysis of hospitalization data of children aged 0-4 years in Brazilian public health system with an admission diagnosis of pneumonia from 2002 to 2012 was performed comparing pre (2002-2009) and post-vaccination periods (2011-2012). Hospital number of admission due to pneumonia and all non-respiratory diseases were obtained from DATASUS, the Brazilian government open-access public health database system. Incidence of pneumonia hospitalization was compared to incidence of all non-respiratory admissions.

RESULTS

Admission rates for pneumonia decreased steadily from 2010 to 2012. In children aged less than four years, incidence of pneumonia hospitalizations decreased 12.65% when pre (2002-2009) and post-vaccination introduction periods (2011-2012) were compared and adjusted for seasonality and secular-trend (p<0.001). On the other hand, non-respiratory admission rates remained stable comparing both periods (p=0.39).

CONCLUSION

Childhood pneumonia hospitalization rates were fluctuating prior to 2010 and decreased significantly in the two years after PHiD-CV introduction. Conversely, rate of non-respiratory admissions has shown no decrease. These data are an evidence of the effectiveness and public health impact of this new pneumococcal vaccine.

Impact of pneumococcal conjugate vaccines on the incidence of pneumonia in hospitalized children after five years of its introduction in Uruguay

BACKGROUND

Data on the burden of pneumococcal disease and the most frequent serotypes demonstrated that invasive disease and pneumonia were important manifestations affecting children under 5 years of age. Therefore, pneumococcal diseases prevention became a public health priority. Uruguay was the first Latin American country to incorporate PCV7 into its National Immunization Program. The aim of this study is to compare the incidence rates for hospitalized pneumonia in children from the pre PCV introduction period and the following five years of PCVs application in Uruguay.

METHODS AND FINDINGS

Population-based surveillance of pneumonia hospitalization rates, in children, less than 14 years of age, had been performed prior pneumococcal vaccination, and continued following PCV7 introduction and PCV13 replacement, using the same methodology. Hospitalized children with pneumonia were enrolled from January 1, 2009 through December 31st, 2012. The study was carried out in an area with a population of 238,002 inhabitants of whom 18, 055 were under five years of age. Patients with acute lower respiratory infections for whom a chest radiograph was performed on admission were eligible. Digitalized radiographs were interpreted by a reference radiologist, using WHO criteria. Pneumonia was confirmed in 2,697 patients, 1,267 with consolidated and 1,430 with non consolidated pneumonia of which incidence decrease, between 2009 and 2012, was 27.3% and 46.4% respectively. 2001-2004 and 2009-2012 comparison showed a significant difference of 20.4% for consolidated pneumonia hospitalizations. A significant incidence decline was recorded among children 6 to 35 months of age.

CONCLUSIONS

An overall significant reduction in pneumonia hospitalizations was observed following the introduction of PCV7 and furthermore following the change to PCV13.

Efficacy of pneumococcal nontypable Haemophilus influenzae protein D conjugate vaccine (PHiD-CV) in young Latin American children: A double-blind randomized controlled trial

BACKGROUND

The relationship between pneumococcal conjugate vaccine-induced antibody responses and protection against community-acquired pneumonia (CAP) and acute otitis media (AOM) is unclear. This study assessed the impact of the ten-valent pneumococcal nontypable Haemophilus influenzae protein D conjugate vaccine (PHiD-CV) on these end points. The primary objective was to demonstrate vaccine efficacy (VE) in a per-protocol analysis against likely bacterial CAP (B-CAP: radiologically confirmed CAP with alveolar consolidation/pleural effusion on chest X-ray, or non-alveolar infiltrates and C-reactive protein ≥ 40 µg/ml); other protocol-specified outcomes were also assessed.

METHODS AND FINDINGS

This phase III double-blind randomized controlled study was conducted between 28 June 2007 and 28 July 2011 in Argentine, Panamanian, and Colombian populations with good access to health care. Approximately 24,000 infants received PHiD-CV or hepatitis control vaccine (hepatitis B for primary vaccination, hepatitis A at booster) at 2, 4, 6, and 15-18 mo of age. Interim analysis of the primary end point was planned when 535 first B-CAP episodes, occurring ≥2 wk after dose 3, were identified in the per-protocol cohort. After a mean follow-up of 23 mo (PHiD-CV, n = 10,295; control, n = 10,201), per-protocol VE was 22.0% (95% CI: 7.7, 34.2; one-sided p = 0.002) against B-CAP (conclusive for primary objective) and 25.7% (95% CI: 8.4%, 39.6%) against World Health Organization-defined consolidated CAP. Intent-to-treat VE was 18.2% (95% CI: 5.5%, 29.1%) against B-CAP and 23.4% (95% CI: 8.8%, 35.7%) against consolidated CAP. End-of-study per-protocol analyses were performed after a mean follow-up of 28-30 mo for CAP and invasive pneumococcal disease (IPD) (PHiD-CV, n = 10,211; control, n = 10,140) and AOM (n = 3,010 and 2,979, respectively). Per-protocol VE was 16.1% (95% CI: -1.1%, 30.4%; one-sided p = 0.032) against clinically confirmed AOM, 67.1% (95% CI: 17.0%, 86.9%) against vaccine serotype clinically confirmed AOM, 100% (95% CI: 74.3%, 100%) against vaccine serotype IPD, and 65.0% (95% CI: 11.1%, 86.2%) against any IPD. Results were consistent between intent-to-treat and per-protocol analyses. Serious adverse events were reported for 21.5% (95% CI: 20.7%, 22.2%) and 22.6% (95% CI: 21.9%, 23.4%) of PHiD-CV and control recipients, respectively. There were 19 deaths (n = 11,798; 0.16%) in the PHiD-CV group and 26 deaths (n = 11,799; 0.22%) in the control group. A significant study limitation was the lower than expected number of captured AOM cases.

CONCLUSIONS

Efficacy was demonstrated against a broad range of pneumococcal diseases commonly encountered in young children in clinical practice.

TRIAL REGISTRATION

www.ClinicalTrials.gov NCT00466947.

A retrospective study to assess the epidemiological and economic burden of pneumococcal diseases in adults aged 50 years and older in Taiwan

OBJECTIVE

Invasive pneumococcal disease (IPD) and pneumococcal pneumonia cause substantial morbidity and mortality worldwide. This retrospective study was conducted to estimate the disease burden from pneumococcal disease in older adults in Taiwan from a health insurer's perspective.

METHODS

Data for the years 2002-2009 from patients aged ≥50 years with insurance records indicating pneumococcal meningitis, pneumococcal bacteremia, or hospitalized or outpatient pneumonia were obtained from the National Health Insurance Research Database in Taiwan. Admission data for inpatients, visit data for outpatients, and associated costs were extracted from the database to estimate the incidence, case fatality rates, and direct and indirect costs of pneumococcal disease episodes. These data were applied to the estimated population of Taiwan in 2010 to provide an estimated disease burden for a single year from the payer perspective.

RESULTS

The average incidence per 100,000 person years was 2.4 for IPD, 278.8 for hospitalized pneumococcal pneumonia, and 1376.4 for outpatient pneumococcal pneumonia. The average case fatality rate was 12.3% for IPD and 10.0% for hospitalized pneumonia. Hospitalized pneumonia accounted for over 90% of direct medical costs. The incidence of hospitalized pneumococcal pneumonia per 100,000 person years was 84.4 for adults of 50-64 years, 313.1 for adults of 65-74 years, 820.3 for adults of 75-84 years, and 1650.9 for adults of 85+ year of age. In 2010, it was estimated there were over 113,000 episodes of pneumococcal disease, causing almost 2000 deaths, with direct medical costs of more than NT$3.4 billion annually.

CONCLUSIONS

Pneumococcal disease is a significant cause of mortality and excess healthcare expense among the elderly in Taiwan. Disease burden in older adults increases with advancing age.

Characteristics of invasive pneumococcal disease in hospitalized children in Austria

In a prospective surveillance study covering all pediatric wards in Austria, 308 cases of invasive pneumococcal disease (IPD) were reported in hospitalized children <5 years of age between 2002 and 2012. Incidence was 7.1 per 100,000 per year for IPD with a case fatality rate of 3 %, and 1.9 per 100,000 per year for pneumococcal meningitis with a case fatality rate of 9 %. At hospital discharge, 17 % of the children were not fully recovered and suffered from problems such as hearing or motor deficits. Persistent sequelae 6 months after hospital discharge were present in 13 % of the children, a finding that emphasizes the seriousness of IPD. From 2007 onwards, we observed a shift of pneumococcal serotypes from those covered by the heptavalent vaccine to serotypes consequently added to 10- and 13-valent vaccines, particularly regarding serotype 19A. Among antimicrobial resistances detected, macrolide resistance was predominant; however, between 2002 and 2012, we saw an overall decrease of resistance rates.

CONCLUSION

Considering this change of serotypes and the high rate of permanent sequelae after IPD, our data show the importance of pediatric pneumococcal vaccination and the relevance of continuous monitoring of circulating serotypes. By the end of 2012, which was the first year of universal mass vaccination against pneumococcal disease in Austria, no change in the incidence of invasive pneumococcal disease was observed yet.

Early impact of sequential introduction of 7-valent and 13-valent pneumococcal conjugate vaccine on IPD in Israeli children <5 years: an active prospective nationwide surveillance

BACKGROUND

The 7-valent pneumococcal conjugated vaccine (PCV7) was introduced to the Israeli national immunization plan (NIP) in July 2009 (administered at age 2, 4 and 12 months), with a fast reduction of invasive pneumococcal disease (IPD) caused by PCV7 serotypes. Starting in November 2010, PCV13 gradually replaced PCV7.

AIM

To report the impact of PCV7/PCV13 sequential introduction on IPD in Israeli children <5 years.

METHODS

An ongoing nationwide, prospective, population-based, active surveillance. All IPD episodes (Streptococcus pneumoniae isolated from blood and/or cerebrospinal fluid) from July 2004 through June 2013 were included.

RESULTS

Overall, 2670 IPD episodes were recorded. Incidence of IPD caused by PCV7+6A serotypes during the PCV13 period vs. pre-PCV period decreased by 95% (Incidence Rate Ratio [IRR]=0.05; 95% CI=0.03-0.09). This reduction was observed in a two-step manner: 90% in the PCV7-period and further 5% in the PCV13-period. The rates of IPD caused by the 5 additional PCV13-serotypes (1, 3, 5, 7F, 19A; 5VT) increased initially by 47%, but subsequently decreased by 79%, resulting in an overall 70% reduction during the entire study period (IRR=0.30; 0.21-0.44). A two-fold increase in non-PCV13 serotypes IPD was observed (IRR=2.43; 1.73-3.66). In total, a 63% reduction of all-serotype IPD episodes was observed in children <5 years (69% and 48% in children <2 and 2-4 years old, respectively).

CONCLUSIONS

After initiation of PCV NIP, a rapid and substantial 2-step IPD reduction was observed in children <5 years. The serotype-specific rate reduction reflected the sequential introduction of PCV7/PCV13.

Reduced incidence of invasive pneumococcal disease after introduction of the 13-valent conjugate vaccine in Navarre, Spain, 2001-2013

Pneumococcal conjugate vaccines (PCVs) were licensed for use in children and became available for private purchase in Spain in 2001 (PCV7), 2009 (PCV10) and 2010 (PCV13). This study evaluates changes in the incidence of invasive pneumococcal disease (IPD) and the pattern of serotypes isolated in Navarre, Spain, between the period of use of PCV7 (2004-2009) and that of PCV13 (2010-2013). The percentage of children <2 years who received at least one dose of PCV in these periods ranged from 25 to 61% and 61 to 78%, respectively. Between the periods 2004-2009 and 2010-2013 IPD incidence declined by 37%, from 14.9 to 9.4 cases/100,000 inhabitants (p<0.001). In children <5 years it fell by 69% (p<0.001), in persons aged 5-64 years, by 34% (p<0.001), and in those ≥ 65, by 23% (p=0.024). The incidence of cases due to PCV13 serotypes declined by 81% (p<0.001) in children <5 years and by 52% (p<0.001) in the whole population. No significant changes were seen in the distribution of clinical presentations or in disease severity. The incidence of IPD has declined and the pattern of serotypes causing IPD has changed notably in children and moderately in adults following the replacement of PCV7 by PCV13.

Regional advisory board position statement on optimal pneumococcal vaccination in adults. Update to 2011 consensus on adult pneumococcal disease: update on optimal pneumococcal vaccination in adults

BACKGROUND

An important development in the field of adult pneumococcal vaccination since the last Consensus Statement, published by the Expert Panel of Central and Eastern Europe and Israel (the Region) in September 2012, was the licensure of the 13-valent pneumococcal conjugate vaccine (PCV13) for adults aged 50 years and older.

DISCUSSION

The Expert Panel has developed this Position Statement as an update to its previous Consensus to address the following topics which are likely to be on the agenda of national scientific societies during the ongoing updates of vaccination recommendations in the Region: the availability of a pneumococcal conjugate vaccine for adults over 50 years of age, the available clinical evidence on its use in adults, and the future place of conjugate vaccines in adult pneumococcal vaccination. The Expert Panel concluded that there is sufficient epidemiologic immunogenicity and safety evidence to use PCV 13 in adults over 50 years of age.

RESULTS

The use of conjugate vaccine induces immunological memory and can overcome some limitations associated with the plain polysaccharide vaccine (PPV). It was also agreed that, if the use of PPV is considered appropriate, PCV13 should be administered first, regardless of prior pneumococcal vaccination status.

Can the success of pneumococcal conjugate vaccines for the prevention of pneumococcal diseases in children be extrapolated to adults?

Before conjugate pneumococcal vaccines (PCVs) were introduced it was estimated that Streptococcus pneumoniae caused 500,000 cases of pneumonia, 50,000 cases of bacteremia and 3000 cases of meningitis annually in the United States in both children and adults. After 10 years of routine use of the 7-valent pneumococcal conjugate vaccine (PCV7) the incidence of vaccine-type pneumococcal diseases (PDs) had significantly decreased in vaccinated children (direct effect) and unvaccinated subjects of all ages (indirect effect). Second generation, higher-valent PCVs, especially 13-valent (PCV13), routinely implemented since 2010, have reduced the incidence of PDs caused by the six additional non-PCV7 serotypes, in both vaccinated and unvaccinated subjects. The licence for this vaccine has recently been extended to include adults aged 18 to 49 in Europe. Although PCV13 has an indirect effect on IPD in adults, this will probably not achieve the same level of disease control in adults and the elderly (especially those at high risk) as that obtained in vaccinated children. As highlighted in this paper, differences exist between children and adults for PD manifestations (incidence, morbidity and mortality) and serotypes isolated in nasopharyngeal carriage and diseases, so benefits from adult vaccination must be considered in this light. PCV13 induces an immune response in adults that is non-inferior for all serotypes common with the 23-valent plain polysaccharide vaccine that is currently recommended for adults and even superior for many serotypes. Although there is no evidence that this immune response translates to clinical efficacy in adults as seen in children, the results from a randomised trial in The Netherlands, expected in 2014, should provide the missing evidence. This evidence and efficient surveillance systems should provide the necessary data, essential for policy makers in their decisions on adult pneumococcal vaccination policies.

Towards New Broader Spectrum Pneumococcal Vaccines: The Future of Pneumococcal Disease Prevention

Seven-valent pneumococcal conjugate vaccine (PCV7) introduction and routine pediatric use has substantially reduced the burden of Streptococcus pneumoniae disease worldwide. However, a significant amount of disease burden, due to serotypes not contained in PCV7, still exists globally. A newly recognized serotype, 6C, was until recently, identified and reported as serotype 6A. This review summarizes the serotype epidemiology of pneumococcal disease pre- and post-introduction of PCV7, available post-marketing surveillance data following the introduction of higher valency pneumococcal vaccines (PCV10, PCV13) and future prospects for the development of new pneumococcal vaccines.

Pneumococcal serotype distribution in 1315 nasopharyngeal swabs from a highly vaccinated cohort of Italian children as detected by RT-PCR

The long term impact of 7-valent pneumococcal conjugate vaccine (PCV7) on pneumococcal colonization patterns remains unclear. Carriage and distribution of Streptococcus pneumoniae serotypes as detected by RT-PCR were evaluated in a cohort of 1315 children. S. pneumoniae was identified in the nasopharyngeal swab of 734 children (55.8%); 488/734 (66.5%) children carried more than 1 pneumococcal serotype. As a consequence of co-colonization, a total of 1,728 S. pneumoniae (belonging to 33 serotypes) were identified. As immunogenicity between 2 and 3 doses of PCV7 in the first year of life has been demonstrated to be similar, serotypes distribution was evaluated categorizing vaccination status as 0,1 and 2 or more doses in the first year of life. Among children who started vaccination in the first year of life, PCV7 serotypes were carried in 296 of 1,123 (29.5%) children who had received ≥2 PCV7 doses while were carried in 26 of 108 (26.8%) who had received no doses (p=not significant); only 17 children received 1 PCV7 and 3 of them were found positive for PCV7 serotypes. Among those who had received ≥2 doses of PCV7 in the first year of life, 47 of 192 (19.7%) carried a PCV7 serotype during the first year after last vaccination, 50 of 125 (28.6%) during the second year, 79 of 224 (35.3%) during the third year, and 65 of 143 (45.5%) during the fourth year (p 0.0001). We did not identify risk factors for PCV7 carriage among children that had received >2 vaccine doses. This study suggests that S. pneumoniae is present in the nasopharynx of the majority of children 0-5 years even if vaccinated, that PCV7 serotypes can be found in nasopharyngeal swabs of PCV7 vaccinated children and that the frequency of PCV7 serotypes increases with the increase of interval from vaccination.

Pneumococcal infection in adults: burden of disease

To overview the present global burden of pneumococcal disease is important because new preventive measures such as the pneumococcal conjugate vaccine 13 are currently being evaluated. Pneumococcal disease is roughly divided into non-invasive and invasive disease. The burden of non-invasive pneumococcal disease in adults is mainly determined by community-acquired pneumonia. Pneumococcal pneumonia has high incidence rates and carries a high mortality risk, especially in the elderly. Within the cluster of invasive pneumococcal diseases, pneumonia also represents the most common infectious source. Incidence and mortality rates of both non-invasive and invasive disease have changed as a result of pneumococcal vaccination in children. However, especially elderly patients with comorbidities remain vulnerable to morbidity and mortality caused by pneumococcal disease. The current review summarizes the current knowledge on the epidemiology including outcome of the main clinical forms of pneumococcal disease, with a special focus on elderly patients. Furthermore, the economic burden and future vaccine strategies are briefly discussed.

Age-dependent prevalence of nasopharyngeal carriage of streptococcus pneumoniae before conjugate vaccine introduction: a prediction model based on a meta-analysis

Introduction

Data on the prevalence of nasopharyngeal carriage of S.pneumoniae in all age groups are important to help predict the impact of introducing pneumococcal conjugate vaccines (PCV) into routine infant immunization, given the important indirect effect of the vaccine. Yet most carriage studies are limited to children under five years of age. We here explore the association between carriage prevalence and serotype distribution in children aged ≥5 years and in adults compared to children.

Methods

We conducted a systematic review of studies providing carriage estimates across age groups in healthy populations not previously exposed to PCV, using MEDLINE and Embase. We used Bayesian linear meta-regression models to predict the overall carriage prevalence as well as the prevalence and distribution of vaccine and nonvaccine type (VT and NVT) serotypes in older age groups as a function of that in <5 y olds.

Results

Twenty-nine studies compromising of 20,391 individuals were included in the analysis. In all studies nasopharyngeal carriage decreased with increasing age. We found a strong positive linear association between the carriage prevalence in pre-school childen (<5 y) and both that in school aged children (5–17 y olds) and in adults. The proportion of VT serotypes isolated from carriers was consistently lower in older age groups and on average about 73% that of children <5 y among 5–17 y olds and adults respectively. We provide a prediction model to infer the carriage prevalence and serotype distribution in 5–17 y olds and adults as a function of that in children <5 years of age.

Conclusion

Such predictions are helpful for assessing the potential population-wide effects of vaccination programmes, e.g. via transmission models, and thus assist in the design of future pneumococcal conjugate vaccination strategies.

Potential opportunities and perils of imperfect dengue vaccines

Dengue vaccine development efforts have focused on the development of tetravalent vaccines. However, a recent Phase IIb trial of a tetravalent vaccine indicates a protective effect against only 3 of the 4 serotypes. While vaccines effective against a subset of serotypes may reduce morbidity and mortality, particular profiles could result in an increased number of cases due to immune enhancement and other peculiarities of dengue epidemiology. Here, we use a compartmental transmission model to assess the impact of partially effective vaccines in a hyperendemic Thai population. Crucially, we evaluate the effects that certain serotype heterogeneities may have in the presence of mass-vaccination campaigns. In the majority of scenarios explored, partially effective vaccines lead to 50% or greater reductions in the number of cases. This is true even of vaccines that we would not expect to proceed to licensure due to poor or incomplete immune responses. Our results show that a partially effective vaccine can have significant impacts on serotype distribution and mean age of cases.

Incidence of pediatric invasive pneumococcal disease in the Island of Majorca (2008-2010), an area with non-universal vaccination, and estimations of serotype & children population coverage by available conjugate vaccines

BACKGROUND

The World Health Organization reported in 2007 that inclusion of PCV7 in national immunization programs should be seen as a priority, also encouraging countries to conduct appropriate surveillances for monitoring the impact of vaccination. These analyses should be conducted in specific geographical areas and should be aimed to evolution of invasive pneumococcal disease (IPD), by age groups, clinical presentation, and vaccine serotypes (and non-vaccine serotypes to detect possible replacement). This study aimed to monitor the evolution of IPD incidence in children <15 years requiring hospitalization in the Island of Majorca.

METHODS

A prospective clinical surveillance of all culture and/or PCR-confirmed IPD in children <15 years was performed in all hospitals in the Island of Majorca (approximately 900,000 inhabitants) from January 2008 to December 2010. Incidence rate (IR) was calculated as cases/100,000 inhabitants using children population data.

RESULTS

66 IPDs were identified: 39 (59.1%) parapneumonic pneumococcal empyema (PPE), 16 (24.2%) bacteremic pneumonia (BP), 7 (10.6%) primary bacteremia, 3 (4.5%) meningitis, and 1 (1.5%) osteomyelitis. IRs in the three-year study period were: 64.22 for children 12- < 24 months, 37.21 for those 24-59 months, 22.62 for those <12 months, and 3.98 for children >59 months. By study year, IRs were 21.25 in 2008, 19.89 in 2009 and 9.80 in 2010. The reduction found in 2010 was significant and due to significant reductions in IRs of IPDs caused by serotypes included in PCV10 and PCV13. Overall, estimated serotype coverage by conjugate vaccines was 12.1% for PCV7, 37.9% for PCV10 and 65.2% for PCV13. Of the 66 hospitalized children with IPD, 20 had received at least one dose of PCV7 (13 cases with identified serotype). None of these 13 cases was caused by PCV7 serotypes, all were caused by PCV13 serotypes and only 53.8% by PCV10 serotypes.

CONCLUSIONS

The results of the present study evidence the importance of expanding the number of serotypes covered by PCV, and the added value of PCV13 with respect to PCV10 and PCV7, even in an area of low prevalence of 19A as the Island of Majorca.

13-valent pneumococcal conjugate vaccine: a review of its use in infants, children, and adolescents

The 13-valent pneumococcal conjugate vaccine (Prevenar 13(®); Prevnar 13(®)) [PCV13] includes 13 serotype-specific polysaccharides of Streptococcus pneumoniae conjugated individually to non-toxic diphtheria CRM197 protein, thus providing wider coverage of pneumococcal serotypes than its 7-valent predecessor (PCV7). For pediatric populations, PCV13 was initially approved for use in infants and children up to 5 years of age, but recently received approval for expanded use (ages 6 weeks to 17 years) in the EU and the USA. This change in labeling was made primarily on the basis of results of Study 3011, which demonstrated the serotype-specific immunogenicity of a single dose of PCV13 in children ≥5 to <10 years of age who had previously received PCV7. Study 3011 also demonstrated functional immune responses after a single dose of PCV13 in a cohort ≥10 to <18 years of age who had not previously received PCV7. Importantly, prior to Study 3011, several randomized studies comparing PCV13 and PCV7 in infants and younger children demonstrated noninferiority of immune responses to the seven serotypes common to both vaccines after a two- or three-dose primary infant series and after the toddler booster dose; immunogenicity and functional immune responses were also demonstrated for the six additional serotypes. The safety and reactogenicity of PCV13 was generally similar to that of PCV7, and PCV13 did not interfere with the immune responses to coadministered routine pediatric vaccines. PCV13 is expected to substantially reduce the incidence of invasive pneumococcal diseases in a manner similar to that which occurred after PCV7 was introduced, and evidence of the protective effectiveness of PCV13 against pneumococcal diseases is emerging.

Expansion of serotype coverage in the universal pediatric vaccination calendar: short-term effects on age- and serotype-dependent incidence of invasive pneumococcal clinical presentations in Madrid, Spain

In Madrid, Spain, the 13-valent pneumococcal conjugate vaccine (PCV13) replaced PCV7 in the pediatric universal vaccination calendar in June 2010. A prospective clinical surveillance that included all children hospitalized with culture- and/or PCR-confirmed invasive pneumococcal disease (IPD) was performed in all Madrid hospitals. The incidence rates (IRs) (defined as the number of cases/100,000 inhabitants aged <15 years) in the PCV7 (May 2007 to April 2010) versus PCV13 (May 2011 to April 2012) periods were compared. There were 499 cases in the PCV7 period and 79 cases in the PCV13 period. Globally, the IR significantly decreased from 17.09 (PCV7 period) to 7.70 (PCV13 period), with significant decreases (PCV7 versus PCV13 periods) in all age groups for bacteremic pneumonia (5.51 versus 1.56), parapneumonic pneumococcal empyema (PPE) (5.72 versus 3.12), and meningitis (2.16 versus 0.97). In the PCV13 period, significant reductions (the IR in the PCV7 period versus the IR in the PCV13 period) were found in IPDs caused by PCV13 serotypes (13.49 versus 4.38), and specifically by serotypes 1 (globally [4.79 versus 2.53], for bacteremic pneumonia [2.23 versus 0.97], and for PPE [2.26 versus 1.17]), serotype 5 (globally [1.88 versus 0.00], for bacteremic pneumonia [0.89 versus 0.00], and for PPE [0.55 versus 0.00]), and serotype 19A (globally [3.77 versus 0.49], for bacteremic pneumonia [0.72 versus 0.00], for PPE [0.89 versus 0.00], and for meningitis [0.62 versus 0.00]). IPDs caused by non-PCV13 serotypes did not increase (IR, 3.60 in the PCV7 period versus 3.31 in the PCV13 period), regardless of age or presentation. No IPDs caused by the PCV13 serotypes were found in children who received 3 doses of PCV13. The number of hospitalization days and sanitary costs were significantly lower in the PCV13 period. The switch from PCV7 to PCV13 in the universal pediatric vaccination calendar provided sanitary and economical benefits without a replacement by non-PCV13 serotypes.

The potential for pneumococcal vaccination in Hajj pilgrims: expert opinion

Hajj is the annual pilgrimage to Mecca in the Kingdom of Saudi Arabia, and is one of the largest mass gathering events in the world. Acute respiratory tract infections are very common during Hajj, primarily as a result of close contact among pilgrims, intense congestion, shared accommodation and air pollution. A number of vaccines are (or have been) recommended for Hajj pilgrims in recent years. Several additional vaccines could significantly reduce the morbidity and mortality at Hajj and should be considered in health recommendations for pilgrims. Pneumococcal vaccines (particularly for those aged >65 years) are widely available, and have been shown to reduce the burden of disease associated with Streptococcus pneumoniae infection. Importantly, a considerable percentage of Hajj pilgrims have pre-existing illnesses or are elderly, both important risk factors for pneumococcal infection. While there are substantial gaps that need to be addressed regarding our knowledge of the exact burden of disease in Hajj pilgrims and the effectiveness of pneumococcal vaccination in this population, S. pneumoniae may be an important cause of illness among this group of travelers. It can be assumed that the majority of pneumococcal serotypes circulating during Hajj are included in the existing pneumococcal vaccines.

Impact of introduction of conjugate vaccines in the vaccination schedule on the incidence of pediatric invasive pneumococcal disease requiring hospitalization in Madrid 2007 to 2011

BACKGROUND

Differences in invasive pneumococcal disease (IPD) in children are expected after a change from 7-valent pneumococcal conjugate vaccine (PCV7) to 13-valent pneumococcal conjugate vaccine (PCV13). Universal vaccination with PCV7 started in Madrid in November 2006, and it switched to PCV13 in June 2010.

METHODS

A prospective, laboratory-confirmed (by culture or polymerase chain reaction), clinical surveillance including all pediatric IPD requiring hospitalization in Madrid was performed in all hospitals with a pediatric department and included four 1-year periods from May 2007 to April 2011. Incidence rate (IR) was calculated as number cases per 100,000 inhabitants using children population data.

RESULTS

Six hundred fourteen IPDs were identified: 209 parapneumonic pneumococcal empyema, 191 bacteremic pneumonia, 75 primary bacteremia, 72 meningitis, 38 IPDs secondary to otic foci and 29 others. The incidence of IPD remained unchanged during 2007-2010 (IR=≈17.0), with a marked decrease in 2010-2011 (IR=11.34; P<0.05) attributable to reduction in children younger than 24 months (50.19 in 2008-2009 compared with 24.92 in 2010-2011; P<0.005). The incidence of bacteremic pneumonia (R²=0.966; β=1.132; P=0.017) and meningitis (R²=0.898; β=0.505; P=0.052) showed decreasing linear trends over time. The incidence of parapneumonic pneumococcal empyema increased in 2009-2010 but decreased in 2010-2011 (6.73 vs. 4.14; P=0.019). The incidence of IPDs by PCV13 serotypes was significantly (P≤0.004) lower in 2010-2011 (8.78) than in previous periods (IR=≈13.5).

CONCLUSIONS

Early data regarding changing from PCV7 to PCV13 use in the childhood vaccination calendar indicate that reductions in IR of bacteremic pneumonia and meningitis after PCV7 introduction (by reduction of cases by serotypes 1 and 19A) further decreased and there was a reversion of the increase in IR of parapneumonic pneumococcal empyema from 2010-2011, mainly because of reduction in serotype 1 and 19A cases.

Trends in prevalence and characteristics of post-neonatal cerebral palsy cases: a European registry-based study

The present paper aims to analyze trends over time in prevalence of cerebral palsy of post-neonatal origin, to investigate whether changes are similar according to severity and to describe the disability profile by etiology. Post-neonatal cases, birth years 1976 to 1998, were identified from the Surveillance of Cerebral Palsy in Europe collaboration (19 population-based registries). A recognized causal event occurring between 28 days and 24 months of age was considered to define the cases. Trends in prevalence were explored using graphical methods (Lowess and Cusum control chart) and modeled with negative binomial regressions. Over the study period, 404 cases were identified as post-neonatal cases (5.5% of the total). Mean prevalence rate was 1.20 per 10,000 live births (95% CI [1.08-1.31]). A significant downward trend was observed (p=0.001), with an accentuated decrease in the 1990 s. The prevalence of severe cases which account for around one third of the total also significantly decreased over time (p<0.001). In 46% of cases, an infectious aetiology was reported; the corresponding prevalence significantly decreased since 1989. No significant decrease was observed for the rate of cases due to a vascular episode or of traumatic origin. Our results emphasize the need of large population-based surveillance systems to reliably monitor trends in prevalence in rare subgroups of children like those with acquired cerebral palsy. The decrease of the overall prevalence as well as those of the most severe cases may be partly due to public health actions targeted to prevent such events.

The need for translational research in respiratory medicine

Medical advances have failed to arrest the growing morbidity and mortality from lung diseases. COPD, lung cancer and pulmonary infections remain leading causes of death. More than any other time in human history, we need high quality, translatable, patient-focussed respiratory research that will improve clinical practice. Close teamwork of scientists and clinicians are essential. The results of these work need to be disseminated quickly and widely. The creation of an open access journal, such as Translational Respiratory Medicine, dedicated to translational respiratory research can help foster progress.