Efficacy, safety and immunogenicity of heptavalent pneumococcal conjugate vaccine in children. Northern California Kaiser Permanente Vaccine Study Center Group

Seroresponses and safety of 13-valent pneumococcal conjugate vaccination in kidney transplant recipients

BACKGROUND

Conjugated pneumococcal vaccine is recommended for kidney transplant recipients, however, their immunogenicity and potential to trigger allograft rejection though generation of de novo anti-human leukocyte antigen antibodies has not been well studied.

METHODS

Clinically stable kidney transplant recipients participated in a prospective cohort study and received a single dose of 13-valent conjugate pneumococcal vaccine. Anti-pneumococcal IgG was measured for the 13 vaccine serotypes pre and post vaccination and functional anti-pneumococcal IgG for 4 serotypes post vaccination. Anti-human leukocyte antigen antibodies antibodies were measured before and after vaccination. Kidney transplant recipients were followed clinically for 12 months for episodes of allograft rejection or invasive pneumococcal disease.

RESULTS

Forty-five kidney transplant recipients participated. Median days between pre and post vaccination serology was 27 (range 21-59). Post vaccination, there was a median 1.1 to 1.7-fold increase in anti-pneumococcal IgG antibody concentrations for all 13 serotypes. Kidney transplant recipients displayed a functional antibody titer ≥1:8 for a median of 3 of the 4 serotypes. Post vaccination, there were no de novo anti-human leukocyte antigen antibodies, no episodes of biopsy proven rejection or invasive pneumococcal disease.

CONCLUSION

A single dose of 13-valent conjugate pneumococcal vaccine elicits increased titers and breadth of functional anti-pneumococcal antibodies in kidney transplant recipients without stimulating rejection or donor-specific antibodies.

A pneumococcal conjugate vaccination programme reduced clinically suspected invasive disease in unvaccinated children

AIM

The 10-valent pneumococcal conjugate vaccine was introduced to the Finnish national vaccination programme for children born since June 2010. We evaluated the changes in the rates of clinically suspected invasive pneumococcal disease (IPD) in unvaccinated children to estimate the indirect herd protection impact of the programme.

METHODS

The target cohort for this ecological before and after comparison were unvaccinated children born from January 2008 to May 2010 and ineligible for the vaccination programme, who were followed up from 2011 to 2014. The reference cohort was age and season-matched children born in January 2003 to 2005 and followed up from 2006 to 2009. National data on hospital discharge codes compatible with IPD or unspecified sepsis were collected.

RESULTS

We compared the follow-up periods of 2007-2009 in the reference cohort and 2012-2014 in the target cohort. The incidence of non-laboratory-confirmed IPD in unvaccinated children fell by 68%, from 47 to 15/100 000 person-years. When unspecified sepsis was added, the decrease was 39%, from 171 to 104/100 000 person-years. Laboratory confirmed IPD fell by 44%, from 15 to 8/100 000 person-years.

CONCLUSION

The pneumococcal vaccination programme provided herd protection against clinically suspected IPD. The absolute reduction was almost 10-times higher than for just laboratory-confirmed disease.

Cochlear implant provider awareness of vaccination guidelines

OBJECTIVE

Guidelines for vaccination of cochlear implant (CI) recipients have been promulgated and updated by the Center for Disease Control and Prevention (CDC) to mitigate bacterial meningitis risk. The objective of this study was to survey current CI specialists on: 1) knowledge of current CDC CI recipient immunization recommendations, and 2) impediments to implementation of those guidelines.

METHODS

A survey to assess knowledge of the CI recipient vaccination guidelines was administered to the American Academy of Otolaryngology-Head and Neck surgery (AAO-HNS), the American Cochlear Implant Alliance (ACIA), and the American Neurotology Society (ANS). The members of the AAO-HNS and ACIA were invited to participate in the survey via an e-mail. The members of the ANS were polled during a session of their fall meeting.

RESULTS

A total of 256 individuals participated: 64 from AAO, 59 from ACIA, and 133 from ANS. Participants reported knowledge of the vaccination guidelines as high among all groups and statistically similar. The survey indicated that the participants noted difficulty in obtaining age-group-specific immunizations. Vaccination status was not consistently reported.

CONCLUSION

Cochlear implant providers have high awareness of vaccination guidelines but less detailed knowledge of age-specific recommendations. Obtaining age-specific vaccines is a challenge, as is consistent documentation of vaccination. Future efforts should be focused on improving knowledge of age-specific recommendations, easing access of age-specific vaccines, and improving documentation.

LEVEL OF EVIDENCE

NA. Laryngoscope, 128:2145-2152, 2018.

Experience with developing antibiotic stewardship programs in Serbia: potential model for other Balkan countries?

Aim: Antimicrobial resistance and inappropriate use of antibiotics in children are important issues. Consequently, there is a need to develop comprehensive stewardship programs even in hospitals with limited resources starting with children's hospitals. Methods: Retrospective observational analysis of antimicrobial utilization and resistance patterns over 5 years in a tertiary care children's hospital in Serbia. Results: Cumulative antimicrobial resistance decreased but was still high, with high cumulative resistance rates among the most widely used antibiotics in the hospital. Total antibiotic use decreased from 2010 to 2014 although there was still high prescribing of reserved antibiotics. Conclusion: Concerns with inappropriate use and high resistance rates among some antibiotics used in the hospital are being used to develop guidance on future antibiotic use in this hospital, building on the recently introduced antibiotic stewardship program, as well as encourage other hospitals in Serbia to review their policies.

Identification of SP1683 as a pneumococcal protein that is protective against nasopharyngeal colonization

Serotype-independent protein-based pneumococcal vaccines represent attractive alternatives to capsular polysaccharide-based vaccines. The aim of this study was to identify novel immunogenic proteins from Streptococcus pneumoniae that may be used in protein-based pneumococcal vaccine. An immunoproteomics approach and a humanized severe combined immunodeficient mouse model were used to identify S. pneumoniae proteins that are immunogenic for the human immune system. Among the several proteins identified, SP1683 was selected, recombinantly produced, and infection and colonization murine models were used to evaluate the capacity of SP1683 to elicit protective responses, in comparison to known pneumococcal immunogenic proteins (PhtD and detoxified pneumolysin, dPly). Immunisation with SP1683 elicited a weaker antibody response than immunisation with PhtD and did not provide protection in the model of invasive disease. However, similar to PhtD, it was able to significantly reduce colonization in the mouse model of nasopharyngeal carriage. Treatment with anti-IL17A and anti-IL17F antibodies abolished the protection against colonization elicited by SP1683 or PhtD + dPly, which indicated that the protection afforded in this model was Th17-dependent. In conclusion, intranasal immunization with the pneumococcal protein SP1683 conferred IL17-dependent protection against nasopharyngeal carriage in mice, but systemic immunization did not protect against invasive disease. These results do not support the use of SP1683 as an isolated pneumococcal vaccine antigen. Nevertheless, SP1683 could be used as a first line of defence in formulations combining several proteins.

Elucidating the impact of the pneumococcal conjugate vaccine programme on pneumonia, sepsis and otitis media hospital admissions in England using a composite control

BACKGROUND

The seven-valent pneumococcal conjugate vaccine (PCV) was introduced in England in September 2006, changing to the 13-valent vaccine in April 2010. PCV impact on invasive pneumococcal disease (IPD) has been extensively reported, but less described is its impact on the burden of pneumonia, sepsis and otitis media in the hospital.

METHODS

Using details on all admissions to hospitals in England, we compared the incidence of pneumococcal-specific and syndromic disease endpoints in a 24-month pre-PCV period beginning April 2004 to the 24-month period ending March 2015 to derive incidence rate ratios (IRRs). To adjust for possible secular trends in admission practice, IRRs were compared to the IRRs for five control conditions over the same period and the relative change assessed using the geometric mean of the five control IRRs as a composite, and individually for each control condition to give the min-max range. Relative changes were also compared with IRRs for IPD from the national laboratory database. The effect of stratifying cases into those with and without clinical risk factors for pneumococcal infection was explored.

RESULTS

Relative reductions in pneumococcal pneumonia were seen in all age groups and in those with and without risk factors; in children under 15 years old reductions were similar in magnitude to reductions in IPD. For pneumonia of unspecified cause, relative reductions were seen in those under 15 years old (maximum reduction in children under 2 years of 34%, min-max: 11-49%) with a relative increase in 65+ year olds most marked in those with underlying risk conditions (41%, min-max: 0-82%). Reductions in pneumococcal sepsis were seen in all age groups, with the largest reduction in children younger than 2 years (67%, min-max 56-75%). Reductions in empyema and lung abscess were also seen in under 15 year olds. Results for other disease endpoints were varied. For disease endpoints showing an increase in raw IRR, the increase was generally reduced when expressed as a relative change.

CONCLUSIONS

Use of a composite control and stratification by risk group status can help elucidate the impact of PCV on non-IPD disease endpoints and in vulnerable population groups. We estimate a substantial reduction in the hospitalised burden of pneumococcal pneumonia in all age groups and pneumonia of unspecified cause, empyema and lung abscess in children under 15 years of age since PCV introduction. The increase in unspecified pneumonia in high-risk 65+ year olds may in part reflect their greater susceptibility to develop pneumonia from less pathogenic serotypes that are replacing vaccine types in the nasopharynx.

Frequency of Acute Otitis Media in Children Under 24 Months of Age Before and After the Introduction of the 10-valent Pneumococcal Conjugate Vaccine Into the National Immunization Program in Chile

BACKGROUND

Streptococcus pneumoniae is the leading cause of acute otitis media (AOM). Ten-valent pneumococcal conjugated vaccine (PCV-10) was introduced to the Chilean National Immunization Program (NIP) in 2011. The aim of this study was to estimate the frequency of AOM in children <24 months of age attending the emergency department (ED) of Hospital Sótero del Río (HSR) 4 years before and 4 years after the introduction of PCV-10 in the Chilean NIP.

METHODS

Register-based nested case-control study. Cases (n = 1907) were all children <24 months of age with a clinical diagnosis discharge of AOM at the ED of HSR, and controls (n = 244,334) were all other children <24 months of age attended at the same ED in the same time period, with any other discharge diagnosis. The data were obtained through HSR Statistical Service.

RESULTS

In the study period, there was a mean of 30,695 children <24 months managed each year at the ED of HSR. The percentage with AOM in the prevaccine period was 0.94% and in the postvaccine period was 0.62%, respectively (P = 0.026). Exposure to the PCV-10 was associated with a decreased risk to develop AOM in children <24 months, with an odds ratio of 0.659 (95% confidence interval: 0.60-0.72).

CONCLUSIONS

Our study showed a significant decrease in the percentage and risk of AOM in children <24 months of age who visited the ED of HSR after implementation of PCV-10 in the NIP in Chile.

Impact of influenza vaccine on childhood otitis media in Taiwan: A population-based study

PURPOSE

Acute otitis media (AOM) is a common infectious disease in children and usually accompanied by a preceding viral respiratory tract infection, especially in the preschool-age population. The study aimed to evaluate impact of influenza vaccine on childhood otitis media.

METHODS

This retrospective cohort study included data for 803,592 children (<10 years old) recorded in Taiwan's National Health Insurance Research Database. AOM incidence and tympanostomy tube insertion incidence in each influenza season before and after the introduction of traditional injectable trivalent influenza vaccine (TIV) were compared using the Poisson regression analysis to estimate the incidence rate ratios (IRRs) and 95% confidence intervals (CIs).

RESULTS

In children < 2 years old, the age group eligible for free influenza vaccination, there was a significant reduction in seasonal AOM incidence after TIV introduction in 2004 (from 98.4 episodes/1000 person-seasons [95% CI: 96.4-100.5] to 66.1 episodes/1000 person-seasons [95% CI: 64-68.1]). In addition, with the increased vaccine coverage rate, the outpatient visits for AOM in the influenza season of 2005 and 2006 were significantly lower than that in 2004 (IRR = 0.85 and 0.80, respectively, p < 0.0001).

CONCLUSIONS

A significant reduction in primary care consultations for children <2 years old was observed after the introduction of the TIV in Taiwan in 2004. With the increased vaccine coverage, there was an additional decline in 2005 and 2006. In addition of the direct protection provided by the vaccination, we believe that TIV may have induced some herd immunity that further contributed to the reduction in influenza attack rates and the rates of associated AOM in that age group. These reductions were observed only in vaccine-eligible children, while older children, who were not enrolled in the influenza vaccination program during the study period, have experienced increases in the AOM incidence during the 2004-2006 period compared to the 2000-2003 period.

Community acquired pneumonia incidence among children less than 5 years of age in Concordia, Argentina: vaccination impact

Objective

To measure the effectiveness of pneumococcal conjugated vaccine (PCV13) against Community Acquired Pneumonia (CAP) and invasive pneumococcal disease, 2 years after the vaccine (2+1) was included into the National Immunization Program of Argentina, and to describe variables associated with bacterial pneumonia and hospitalization.

Methods

This was a prospective, population-based surveillance study of CAP incidence (ambulatory and hospitalized) among children less than 5 years of age in the Department of Concordia (Entre Rios, Argentina) from April 2014 – March 2016. The diagnosis of probable bacterial pneumonia (PBP) was determined following the standardized WHO protocol. Incidence during the post-vaccine introduction period was compared with the results from a previous study that used similar methodology for the pre-PCV13 introduction period from 2002 – 2005.

Results

During the study period, 330 patients had a clinical diagnosis of CAP, of which 92 were PBP (6 with pleural effusion). S. pneumoniae was not isolated from any sample. No factors associated with PBP were found in multivariable analysis. The decrease in PBP and pleural effusion was significant in relation to the previous study: 63% (P < 0.0001) and 80.9% (P < 0.003), respectively. PCV13 uptake was 97.3% for the 1st dose and 84.8% for the booster dose.

Conclusions

PCV13 was effective to reduce incidence of consolidated pneumonia and pleural effusion, among children less than 5 years of age in Concordia, Argentina. Vaccination is a very effective public health strategy for reducing vaccine preventable diseases, with impact on burden of disease and hospitalization.

Neutrophil evasion strategies by Streptococcus pneumoniae and Staphylococcus aureus

Humans are well equipped to defend themselves against bacteria. The innate immune system employs diverse mechanisms to recognize, control and initiate a response that can destroy millions of different microbes. Microbes that evade the sophisticated innate immune system are able to escape detection and could become pathogens. The pathogens Streptococcus pneumoniae and Staphylococcus aureus are particularly successful due to the development of a wide variety of virulence strategies for bacterial pathogenesis and they invest significant efforts towards mechanisms that allow for neutrophil evasion. Neutrophils are a primary cellular defense and can rapidly kill invading microbes, which is an indispensable function for maintaining host health. This review compares the key features of Streptococcus pneumoniae and Staphylococcus aureus in epidemiology, with a specific focus on virulence mechanisms utilized to evade neutrophils in bacterial pathogenesis. It is important to understand the complex interactions between pathogenic bacteria and neutrophils so that we can disrupt the ability of pathogens to cause disease.

Streptococcus pneumoniae and chronic endobronchial infections in childhood

Streptococcus pneumoniae (pneumococcus) is the main cause of bacterial pneumonia worldwide and has been studied extensively in this context. However, its role in chronic endobronchial infections and accompanying lower airway neutrophilic infiltration has received little attention. Severe and recurrent pneumonia are risk factors for chronic suppurative lung disease (CSLD) and bronchiectasis; the latter causes considerable morbidity and, in some populations, premature death in children and adults. Protracted bacterial bronchitis (PBB) is another chronic endobronchial infection associated with substantial morbidity. In some children, PBB may progress to bronchiectasis. Although nontypeable Haemophilus influenzae is the main pathogen in PBB, CSLD and bronchiectasis, pneumococci are isolated commonly from the lower airways of children with these diagnoses. Here we review what is known currently about pneumococci in PBB, CSLD and bronchiectasis, including the importance of pneumococcal nasopharyngeal colonization and how persistence in the lower airways may contribute to the pathogenesis of these chronic pulmonary disorders. Antibiotic treatments, particularly long-term azithromycin therapy, are discussed together with antibiotic resistance and the impact of pneumococcal conjugate vaccines. Important areas requiring further investigation are identified, including immune responses associated with pneumococcal lower airway infection, alone and in combination with other respiratory pathogens, and microarray serotyping to improve detection of carriage and infection by multiple serotypes. Genome wide association studies of pneumococci from the upper and lower airways will help identify virulence and resistance determinants, including potential therapeutic targets and vaccine antigens to treat and prevent endobronchial infections. Much work is needed, but the benefits will be substantial.

USE OF SCORE AND CEREBROSPINAL FLUID LACTATE DOSAGE IN DIFFERENTIAL DIAGNOSIS OF BACTERIAL AND ASEPTIC MENINGITIS

Objective:

To evaluate Bacterial Meningitis Score (BMS) on its own and in association with Cerebrospinal Fluid (CSF) lactate dosage in order to distinguish bacterial from aseptic meningitis.

Methods:

Children diagnosed with meningitis at a tertiary hospital between January/2011 and December/2014 were selected. All data were obtained upon admission. BMS was applied and included: CSF Gram staining (2 points); CSF neutrophil count ≥1,000 cells/mm³ (1 point); CSF protein ≥80 mg/dL (1 point); peripheral blood neutrophil count ≥10,000 cells/mm³ (1 point) and seizures upon/before arrival (1 point). Cutoff value for CSF lactate was ≥30 mg/dL. Sensitivity, specificity and negative predictive value of several BMS cutoffs and BMS associated with high CSF lactate were evaluated for prediction of bacterial meningitis.

Results:

Among 439 eligible patients, 94 did not have all data available to complete the score, and 345 patients were included: 7 in bacterial meningitis group and 338 in aseptic meningitis group. As predictive factors of bacterial meningitis, BMS ≥1 had 100% sensitivity (95%CI 47.3-100), 64.2% specificity (58.8-100) and 100% negative predictive value (97.5-100); BMS ≥2 or BMS ≥1 associated with high CSF lactate also showed 100% sensitivity (47.3-100); but 98.5% specificity (96.6-99.5) and 100% negative predictive value (98.3-100).

Conclusions:

2 point BMS in association with CSF lactate dosage had the same sensitivity and negative predictive value, with increased specificity for diagnosis of bacterial meningitis when compared with 1-point BMS.

Trends in Otitis Media Incidence After Conjugate Pneumococcal Vaccination: A National Observational Study

BACKGROUND

Pneumococcal conjugate vaccine (PCV) was introduced in 2000. The first 7-valent vaccine (PCV7) was followed by a 13-valent vaccine (PCV13) with the same conjugate, and a 10-valent vaccine (PCV10), conjugated to protein D from Haemophilus influenzae. The vaccines offer some protection against pneumococcal acute otitis media (AOM), and, with PCV10, possibly also some protection against H. influenzae AOM. PCV7 was introduced in Sweden in 2009, but from 2010, Swedish counties were free to use either PCV13 or PCV10. The purpose of this study was to investigate the incidence of AOM-related diagnoses and surgical procedures before and after the introduction of PCV in Sweden, but also to compare the areas using PCV13 and PCV10.

METHODS

Data showing the number of AOM diagnoses, ventilation tube insertions, myringotomies, acute mastoiditis cases and mastoidectomies between 2005 and 2014 were extracted from the National Board of Health and Welfare database. Yearly national incidences were calculated, and areas using PCV13 and PCV10 were compared.

RESULTS

AOM incidence decreased, both in outpatients (39%) and hospital admissions (42%). Ventilation tube insertions decreased by 18%, and myringotomies by 15%. The decline in outpatient AOM and ventilation tube insertions was more pronounced in areas that used PCV10, but geographical differences were large also before vaccine introduction.

CONCLUSION

Otitis media-related diagnoses have decreased in Sweden since the introduction of PCV. Though some decreases were more pronounced in areas where PCV10 were used, figures should be interpreted with great caution, because considerable geographical differences were obvious also before vaccine introduction.

Prophylactic antibiotics for preventing pneumococcal infection in children with sickle cell disease

BACKGROUND

Persons with sickle cell disease (SCD) are particularly susceptible to infection. Infants and very young children are especially vulnerable. The 'Co-operative Study of Sickle Cell Disease' observed an incidence rate for pneumococcal septicaemia of 10 per 100 person years in children under the age of three years. Vaccines, including customary pneumococcal vaccines, may be of limited use in this age group. Therefore, prophylactic penicillin regimens may be advisable for this population. This is an update of a Cochrane Review first published in 2002, and previously updated, most recently in 2014.

OBJECTIVES

To assess the effects of antibiotic prophylaxis against pneumococcus in children with SCD in relation to:1. incidence of infection;2. mortality;3. drug-related adverse events (as reported in the included studies) to the individual and the community;4. the impact of discontinuing at various ages on incidence of infection and mortality.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Haemoglobinopathies Trials Register, which is comprised of references identified from comprehensive electronic database searches and also two clinical trials registries: ClinicalTrials.gov and the WHO International Registry Platform. Additionally, we carried out handsearching of relevant journals and abstract books of conference proceedings.Date of the most recent search: 19 December 2016.

SELECTION CRITERIA

All randomised or quasi-randomised controlled trials comparing prophylactic antibiotics to prevent pneumococcal infection in children with SCD with placebo, no treatment or a comparator drug.

DATA COLLECTION AND ANALYSIS

Both authors independently extracted data and assessed trial quality. The authors used the GRADE criteria to assess the quality of the evidence.

MAIN RESULTS

Five trials were identified by the searches, of which three trials (880 children randomised) met the inclusion criteria. All of the included trials showed a reduced incidence of infection in children with SCD (SS or Sβ0Thal) receiving prophylactic penicillin. In trials which investigated initiation of penicillin on risk of pneumococcal infection, the odds ratio was 0.37 (95% confidence interval 0.16 to 0.86) (two trials, 457 children) (low-quality evidence), while for withdrawal the odds ratio was 0.49 (95% confidence interval 0.09 to 2.71) (one trial, 400 children) (low-quality evidence). Adverse drug effects were rare and minor. Rates of pneumococcal infection were found to be relatively low in children over the age of five.Overall, the quality of the evidence for all outcomes was judged to be low. The results from the risk of bias assessment undertaken identified two domains in which the risk of bias was considered to be high, these were incomplete outcome data (attrition bias) (two trials) and allocation concealment (selection bias) (one trial). Domains considered to have a low risk of bias for all three trials were selective reporting (reporting bias) and blinding (performance and detection bias).

AUTHORS' CONCLUSIONS

The evidence examined suggests that prophylactic penicillin significantly reduces risk of pneumococcal infection in children with homozygous SCD, and is associated with minimal adverse reactions. Further research may help to determine the ideal age to safely withdraw penicillin.

Biochemical and Structural Characterization of the Carbohydrate Transport Substrate-binding-protein SP0092

Development of new antimicrobials and vaccines for Streptococcus pneumoniae (pneumococcus) are necessary to halt the rapid rise in multiple resistant strains. Carbohydrate substrate binding proteins (SBPs) represent viable targets for the development of protein-based vaccines and new antimicrobials because of their extracellular localization and the centrality of carbohydrate import for pneumococcal metabolism, respectively. Described here is a rationalized integrated protocol to carry out a comprehensive characterization of SP0092, which can be extended to other carbohydrate SBPs from the pneumococcus and other bacteria. This procedure can aid the structure-based design of inhibitors for this class of proteins. Presented in the first part of this manuscript are protocols for biochemical analysis by thermal shift assay, multi angle light scattering (MALS), and size exclusion chromatography (SEC), which optimize the stability and homogeneity of the sample directed to crystallization trials and so enhance the probability of success. The second part of this procedure describes the characterization of the SBP crystals using a tunable wavelength anomalous diffraction synchrotron beamline, and data collection protocols for measuring data that can be used to resolve the crystallized protein structure.

Comparison of enterovirus detection in cerebrospinal fluid with Bacterial Meningitis Score in children

Objective

To measure the role of enterovirus detection in cerebrospinal fluid compared with the Bacterial Meningitis Score in children with meningitis.

Methods

A retrospective cohort based on analysis of medical records of pediatric patients diagnosed as meningitis, seen at a private and tertiary hospital in São Paulo, Brazil, between 2011 and 2014. Excluded were patients with critical illness, purpura, ventricular shunt or recent neurosurgery, immunosuppression, concomitant bacterial infection requiring parenteral antibiotic therapy, and those who received antibiotics 72 hours before lumbar puncture.

Results

The study included 503 patients. Sixty-four patients were excluded and 94 were not submitted to all tests for analysis. Of the remaining 345 patients, 7 were in the Bacterial Meningitis Group and 338 in the Aseptic Meningitis Group. There was no statistical difference between the groups. In the Bacterial Meningitis Score analysis, of the 338 patients with possible aseptic meningitis (negative cultures), 121 of them had one or more points in the Bacterial Meningitis Score, with sensitivity of 100%, specificity of 64.2%, and negative predictive value of 100%. Of the 121 patients with positive Bacterial Meningitis Score, 71% (86 patients) had a positive enterovirus detection in cerebrospinal fluid.

Conclusion

Enterovirus detection in cerebrospinal fluid was effective to differentiate bacterial from viral meningitis. When the test was analyzed together with the Bacterial Meningitis Score, specificity was higher when compared to Bacterial Meningitis Score alone.

Impact of pneumococcal conjugate vaccines on otitis media: A review of measurement and interpretation challenges

Acute otitis media (AOM) is among the most frequent childhood diseases and is caused by various bacterial and viral etiological agents. In this article, we provide an overview of published studies assessing the impact of higher-valent pneumococcal conjugate vaccines (PCVs) on AOM. In some instances, reports of PCV impact on complications of AOM have been included. While randomized controlled trials (RCTs) allow for the most precise assessment of vaccine efficacy against AOM, observational studies provide answers to questions regarding the public health value of these vaccines in real-life settings. We discuss the challenges that arise when measuring PCV impact on AOM in observational studies: the local variability of viral and bacterial etiology, differences in case ascertainment, care-seeking behavior, standards of care and diagnosis of AOM (e.g. use of incisions), as well as declining baseline AOM incidence that can already be in place before PCV introduction, and how these factors can impact the results and their interpretation.

Population genetic structure, antibiotic resistance, capsule switching and evolution of invasive pneumococci before conjugate vaccination in Malawi

INTRODUCTION

Pneumococcal infections cause a high death toll in Sub Saharan Africa (SSA) but the recently rolled out pneumococcal conjugate vaccines (PCV) will reduce the disease burden. To better understand the population impact of these vaccines, comprehensive analysis of large collections of pneumococcal isolates sampled prior to vaccination is required. Here we present a population genomic study of the invasive pneumococcal isolates sampled before the implementation of PCV13 in Malawi.

MATERIALS AND METHODS

We retrospectively sampled and whole genome sequenced 585 invasive isolates from 2004 to 2010. We determine the pneumococcal population genetic structure and assessed serotype prevalence, antibiotic resistance rates, and the occurrence of serotype switching.

RESULTS

Population structure analysis revealed 22 genetically distinct sequence clusters (SCs), which consisted of closely related isolates. Serotype 1 (ST217), a vaccine-associated serotype in clade SC2, showed highest prevalence (19.3%), and was associated with the highest MDR rate (81.9%) followed by serotype 12F, a non-vaccine serotype in clade SC10 with an MDR rate of 57.9%. Prevalence of serotypes was stable prior to vaccination although there was an increase in the PMEN19 clone, serotype 5 ST289, in clade SC1 in 2010 suggesting a potential undetected local outbreak. Coalescent analysis revealed recent emergence of the SCs and there was evidence of natural capsule switching in the absence of vaccine induced selection pressure. Furthermore, majority of the highly prevalent capsule-switched isolates were associated with acquisition of vaccine-targeted capsules.

CONCLUSIONS

This study provides descriptions of capsule-switched serotypes and serotypes with potential to cause serotype replacement post-vaccination such as 12F. Continued surveillance is critical to monitor these serotypes and antibiotic resistance in order to design better infection prevention and control measures such as inclusion of emerging replacement serotypes in future conjugate vaccines.

Cost-effectiveness of the 13-valent Pneumococcal Conjugate Vaccine in Children in Portugal

BACKGROUND

Pneumococcal infections are the leading cause of vaccine-preventable death in children. In June 2015, the 13-valent pneumococcal conjugate vaccine (PCV13) was introduced in the Portuguese Immunization Program. We evaluated the cost-effectiveness of children vaccinated with PCV13 versus no vaccination for preventing pneumococcal diseases.

METHODS

A cohort simulation model for 2014 Portuguese newborns was used, considering a lifetime horizon and existence of herd effect on adults. Model outcomes measured life years gained, direct and indirect healthcare costs and net benefits considering &OV0556;20,000 per life years gained. PCV13 clinical effectiveness rate by serotype covered was assumed similar to PCV7. Patients' resource use was based on 2014 diagnostic-related group database and experts' opinion, while national legislation and official drug cost database were the main sources for unitary costs. Univariate sensitivity analyses were conducted to assess results' effectiveness.

RESULTS

In base case scenario, PCV13 was a dominant strategy, being associated with better health outcomes and lower costs. In a lifetime, a total of 6238 infections (excluding acute otitis media) and 130 deaths were averted, with a total saving of &OV0556;397,217 ($432,966). Net benefits were estimated above &OV0556;28 million ($30 million). Results were robust in all sensitivity analyses, with positive net benefits, except when herd effect was excluded.

CONCLUSIONS

Vaccination of children with PCV13 starting in their first year of life is a cost-effective intervention with the potential to save costs to the Portuguese health system and to provide health gains by reducing the burden of pneumococcal disease in the vaccines and through the herd effect of this vaccine.

Pneumococcal conjugate vaccine induced IgG and nasopharyngeal carriage of pneumococci: Hyporesponsiveness and immune correlates of protection for carriage

•

We have confirmed hyporesponsiveness in an equatorial African setting in both infants and toddlers.

•

Responses to vaccination are likely to improve with reducing vaccine-serotypes prevalence.

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We have not found clear correlates of protection (CoP) against carriage acquisition.

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Assessing the potential of new vaccines through the use of CoP against carriage is still difficult.

Background

Prior studies have demonstrated hyporesponsiveness to pneumococcal conjugate vaccines (PCVs) when administered in the presence of homologous carriage. This may be substantially more important in Africa where carriage prevalence is high. Deriving a correlate of protection (CoP) for carriage is important in guiding the future use of extended PCVs as population control of pneumococcal disease by vaccination is now focused principally on its indirect effect. We therefore explored the complex relationship between existing carriage and vaccine responsiveness, and between serum IgG levels and risk of acquisition.

Methods

We undertook secondary analyses of data from two previously published clinical trials of the safety and immunogenicity of PCV in Kenya. We compared responses to vaccination between serotype-specific carriers and non-carriers at vaccination. We assessed the risk of carriage acquisition in relation to PCV-induced serum IgG levels using either a step- or continuous-risk function.

Results

For newborns, the immune response among carriers was 51–82% lower than that among non-carriers, depending on serotype. Among toddlers, for serotypes 6B, 14 and 19F the post-vaccination response among carriers was lower by between 29 and 70%. The estimated CoP against acquisition ranged from 0.26 to 1.93 μg/mL across serotypes, however, these thresholds could not be distinguished statistically from a model with constant probability of carriage independent of assay value.

Conclusion

We have confirmed hyporesponsiveness in an equatorial African setting in both infants and toddlers. Population responses to vaccination are likely to improve with time as carriage prevalence of vaccine serotypes is reduced. We have not found clear correlates of protection against carriage acquisition among toddlers in this population. Assessing the potential of new vaccines through the use of CoP against carriage is still difficult as there are no clear-cut serotype specific correlates.

Pneumococcal 7-Valent Conjugate Vaccine

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Sustained reduction in vaccine-type invasive pneumococcal disease despite waning effects of a catch-up campaign in Kilifi, Kenya: A mathematical model based on pre-vaccination data

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We predict a substantial decline in the carriage prevalence of vaccine serotypes.

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About a 56% reduction in invasive pneumococcal disease is also predicted.

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The decline is predicted to be sustainable ten years post-vaccination.

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The current vaccination schedule is unlikely to achieve elimination of vaccine serotypes.

Background

In 2011, Kenya introduced the 10-valent pneumococcal conjugate vaccine together with a catch-up campaign for children aged <5 years in Kilifi County. In a post-vaccination surveillance study based in Kilifi, there was a substantial decline in invasive pneumococcal disease (IPD). However, given the continued circulation of the vaccine serotypes it is possible that vaccine-serotype disease may re-emerge once the effects of the catch-up campaign wear off.

Methods

We developed a compartmental, age-structured dynamic model of pneumococcal carriage and invasive disease for three serotype groups: the 10-valent vaccine serotypes and two groups of non-vaccine serotypes based on their susceptibility to mutual competition. The model was calibrated to age- and serotype-specific data on carriage and IPD in the pre-vaccination era and used to predict carriage prevalence and IPD up to ten years post-vaccination in Kilifi. The model was validated against the observed carriage prevalence after vaccine introduction.

Results

The model predicts a sustained reduction in vaccine-type pneumococcal carriage prevalence from 33% to 8% in infants and from 30% to 8% in 1–5 year olds over the 10-year period following vaccine introduction. The incidence of IPD is predicted to decline across all age groups resulting in an overall reduction of 56% in the population, corresponding to 10.4 cases per 100,000 per year. The vaccine-type IPD incidence is estimated to decline by 83% while non-vaccine-type IPD incidence is predicted to increase by 52%. The model's predictions of carriage prevalence agrees well with the observed data in the first five years post-vaccination.

Conclusion

We predict a sustained and substantial decline in IPD through PCV vaccination and that the current regimen is insufficient to fully eliminate vaccine-serotype circulation in the model. We show that the observed impact is likely to be sustained despite waning effects of the catch-up campaign.

Vaccination ecosystem health check: achieving impact today and sustainability for tomorrow

BACKGROUND

Vaccination is a complex ecosystem with several components that interact with one another and with the environment. Today's vaccine ecosystem is defined by the pursuit of polio eradication, the drive to get as many of the new vaccines to as many people as possible and the research and development against immunologically challenging diseases. Despite these successes, vaccine ecosystem is facing keys issues with regard to supply/distribution and cost/profitability asymmetry that risk slowing its global growth. The conference "Vaccination ecosystem health check: achieving impact today and sustainability for tomorrow" held in Annecy-France (January 19-21, 2015) took stock of the health of today's vaccination ecosystem and its ability to reliably and sustainably supply high-quality vaccines while investing in tomorrow's needed innovation.

MAIN FINDINGS

Small and decreasing numbers of suppliers/manufacturing facilities; paucity of research-driven companies; regulatory pressures; market uncertainties; political prioritization; anti-vaccine movements/complacency; and technological and programmatic issues were acknowledged as the major challenges that could weaken today's vaccination ecosystem. The expert panel discussed also drivers and barriers to a sustainable vaccination ecosystem; the metrics of a vaccination ecosystem; and what should be added, removed, increased, or reduced to maintain the health of the vaccination ecosystem.

Streptococcus pneumoniae antimicrobial resistance decreased in the Helsinki Metropolitan Area after routine 10-valent pneumococcal conjugate vaccination of infants in Finland

Since the introduction of 10-valent pneumococcal conjugate vaccine (PCV10) into the Finnish national vaccination program in September 2010, the incidence of invasive pneumococcal disease in children has decreased steeply in Finland. We studied the antimicrobial susceptibility of invasive and non-invasive Streptococcus pneumoniae (pneumococcus) isolated in the Helsinki Metropolitan Area during 2009-2014. We divided the data into two age groups: isolates from patients <5 years old and ≥5 years old. We also studied the serotype distribution of invasive isolates and of a subset of non-invasive multidrug-resistant isolates. The invasive isolate numbers recovered from patients aged <5 years old declined from 33/228 (15%) in 2009 to 8/208 (4%) in 2014 (p < 0.001) and non-invasive isolate numbers declined during the same time period from 221/595 (37%) to 119/432 (28%) (p < 0.001). At the same time, the proportion of penicillin non-susceptible non-invasive isolates in this age group decreased from 25% (56/220) to 13% (15/119) (p = 0.001) and multidrug-resistant isolates from 22% (49/220) to 6% (7/119) (p < 0.001), respectively. The number of PCV10 serotype isolates also decreased among the serotyped multidrug-resistant non-invasive isolates. Among patients aged ≥5 years old, the isolate numbers did not show a similar decreasing trend compared to the younger group and, further, the number of non-PCV10 serotype isolates increased in invasive cases. To conclude, the antimicrobial non-susceptibility of pneumococcus has decreased markedly, especially among young patients (<5 years old), following PCV10 implementation in Finland.

Geographic variation in pneumococcal vaccine efficacy estimated from dynamic modeling of epidemiological data post-PCV7

Although mean efficacy of multivalent pneumococcus vaccines has been intensively studied, variance in vaccine efficacy (VE) has been overlooked. Different net individual protection across settings can be driven by environmental conditions, local serotype and clonal composition, as well as by socio-demographic and genetic host factors. Understanding efficacy variation has implications for population-level effectiveness and other eco-evolutionary feedbacks. Here I show that realized VE can vary across epidemiological settings, by applying a multi-site-one-model approach to data post-vaccination. I analyse serotype prevalence dynamics following PCV7, in asymptomatic carriage in children attending day care in Portugal, Norway, France, Greece, Hungary and Hong-Kong. Model fitting to each dataset provides site-specific estimates for vaccine efficacy against acquisition, and pneumococcal transmission parameters. According to this model, variable serotype replacement across sites can be explained through variable PCV7 efficacy, ranging from 40% in Norway to 10% in Hong-Kong. While the details of how this effect is achieved remain to be determined, here I report three factors negatively associated with the VE readout, including initial prevalence of serotype 19F, daily mean temperature, and the Gini index. The study warrants more attention on local modulators of vaccine performance and calls for predictive frameworks within and across populations.

Reduction in all-cause otitis media-related outpatient visits in children after PCV10 introduction in Brazil

Few studies have reported the effect of 10-valent pneumococcal conjugate vaccine (PCV10) on otitis media (OM) in infants. In particular, no population-based study in upper-middle income countries is available. In 2010, Brazil introduced PCV10 into its routine National Immunization Program using a 3+1 schedule. We measured the impact of PCV10 on all-cause OM in children. An interrupted time-series analysis was conducted in Goiânia/Brazil considering monthly rates (per 100,000) of all-cause OM outpatient visits in children aged 2–23 months. We used case-based data from the Outpatient Visits Information System of the Unified Health System coded for ICD-10 diagnosis for the period of August/2008 to July/2015. As a comparator, we used rates of outpatient visits due to all-other causes. The relative reduction of all-cause OM and all-other causes of outpatient visits were calculated as the difference between the predicted and observed cumulative rates of the PCV10 post-vaccination period. We then subtracted the relative reduction of all-other causes of outpatient visits from all-cause OM to obtain the impact of PCV10 on OM. In total, 6,401 OM outpatient visits were recorded in 4,793 children aged 2–23 months. Of these, 922 (19.2%) children had more than one OM episode. A significant reduction in all-cause OM visits was observed (50.7%; 95%CI: 42.2–59.2%; p = 0.013), while the reduction in visits due to all-other causes was 7.7% (95% CI 0.8–14.7%; p<0.001). The impact of PCV10 on all-cause OM was thus estimated at 43.0% (95%CI 41.4–44.5). This is the first study to show significant PCV10 impact on OM outpatient visits in infants in a developing country. Our findings corroborate the available evidence from developed countries.

Streptococcus pneumoniae Otitis Media Pathogenesis and How It Informs Our Understanding of Vaccine Strategies

PURPOSE OF REVIEW

This study aimed to review the literature regarding the mechanisms of transition from asymptomatic colonization to induction of otitis media and how the insight into the pathogenesis of otitis media has the potential to help design future otitis media-directed vaccines.

RECENT FINDINGS

Respiratory viruses have long been shown to predispose individuals to bacterial respiratory infections, such as otitis media. Recent information suggests that Streptococcus pneumoniae, which colonize the nasopharynx asymptomatically, can sense potentially "threatening" changes in the nasopharyngeal environment caused by virus infection by upregulating specific sets of genes involved in biofilm release, dissemination from the nasopharynx to other sites, and protection against the host immune system. Furthermore, an understanding of the transcriptional and proteomic changes occurring in bacteria during transition to infection has led to identification of novel vaccine targets that are disease-specific and will not affect asymptomatic colonization. This approach will avoid major changes in the delicate balance of microorganisms in the respiratory tract microbiome due to elimination of S. pneumoniae.

SUMMARY

Our recent findings are reviewed in the context of the current literature on the epidemiology and pathogenesis of otitis media. We also discuss how other otopathogens, such as Haemophilus influenzae and Moraxella catarrhalis, as well as the normal respiratory microbiome, can modulate the ability of pneumococci to cause infection. Furthermore, the unsatisfactory protection offered by the pneumococcal conjugate vaccines is highlighted and we review potential future strategies emerging to confer a more specific protection against otitis media.

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.

Pediatric Acute Otitis Media in the Era of Pneumococcal Vaccination

Objectives

(1) Describe longitudinal trends in annual prevalence of hospital admission for pediatric acute otitis media (AOM) and complications of AOM (CAOM) since introduction of pneumococcal vaccination in 2000 and (2) describe the longitudinal trend of prevalence of hospital admission for pneumococcal meningitis in children with AOM-related diagnoses in the postvaccination era.

Study Design

Retrospective analysis of Kids’ Inpatient Database from 2000 to 2012.

Setting

Community, nonrehabilitation hospitals.

Subjects and Methods

To determine annual prevalence of admission for AOM/CAOM, nationally weighted frequencies of children aged <21 years with acute suppurative otitis media, acute mastoiditis, suppurative labyrinthitis, and/or acute petrositis were collected. The frequency of coexisting pneumococcal meningitis diagnoses among these patients was also collected. Trend analysis of prevalences of admission for AOM/CAOM and for pneumococcal meningitis occurring in the setting of AOM/CAOM from 2000 to 2012 was performed.

Results

Between 2000 and 2012, annual prevalence of admission for AOM/CAOM decreased from 3.956 to 2.618 per 100,000 persons ( P < .0001) (relative risk reduction 34%). Declines in admission prevalence were most pronounced in children <1 year of age (from 22.647 to 8.715 per 100,000 persons between 2000 and 2012, P < .0001) and 1 to 2 years of age (from 13.652 to 5.554 per 100,000 persons between 2000 and 2012, P < .0001). For all ages, the admission prevalence for pneumococcal meningitis and concomitant AOM/CAOM decreased (from 1.760 to 0.717 per 1,000,000 persons, P < .0001) over the study period.

Conclusions

The prevalence of hospital admission for pediatric AOM/CAOM has declined since the advent of pneumococcal vaccination. Admission rates for pneumococcal meningitis with AOM/CAOM have similarly declined.

Etiology of Acute Otitis Media in Children Less Than 5 Years of Age: A Pooled Analysis of 10 Similarly Designed Observational Studies

BACKGROUND

Acute otitis media (AOM) is an important cause of childhood morbidity and antibiotic prescriptions. However, the relative importance of the well-known otopathogens, Streptococcus pneumoniae (Spn) and Haemophilus influenzae (Hflu), remains unclear because of a limited number of tympanocentesis-based studies that vary significantly in populations sampled, case definitions and heptavalent pneumococcal conjugate vaccine use.

METHODS

We conducted a pooled analysis of results from 10 AOM etiology studies of similar design, the protocols of which were derived from a common protocol and conducted in children 3 months to 5 years of age in different countries. Generalized estimating equations were used to account for within-study correlations.

RESULTS

The majority, 55.5% (95% confidence interval: 47.0%-65.7%) of 1124 AOM episodes, were bacterial pathogen positive: 29.1% (24.8%-34.1%) yielded Hflu and 23.6% (19.0%-29.2%) Spn. Proportions of Hflu and Spn were higher and lower, respectively, in heptavalent pneumococcal conjugate vaccine-vaccinated children. Hflu and Spn were each isolated from 20% to 35% of children in every 1-year age range. Hflu was less likely to be isolated from first (vs. subsequent) episodes [relative risk (RR): 0.71 (0.60-0.84)]. Spn was more often isolated from sporadic (vs. recurrent) cases [RR: 0.76 (0.61-0.97)]; the opposite was true for Hflu [RR: 1.4 (1.00-1.96)]. Spn cases were more likely to present with severe (vs. mild) symptoms [RR: 1.42 (1.01-2.01)] and Hflu cases with severe tympanic membrane inflammation [RR: 1.35 (1.06-1.71)].

CONCLUSIONS

Spn and Hflu remain the leading otopathogens in all populations examined. While associated with overlapping symptoms and severity, they exhibit some differences in their likelihood to cause disease in specific subpopulations.

Efficacy of 10-valent pneumococcal non-typeable Haemophilus influenzae protein D conjugate vaccine against acute otitis media and nasopharyngeal carriage in Panamanian children - A randomized controlled trial

We previously reported 10-valent pneumococcal non-typeable Haemophilus influenzae (NTHi) protein D conjugate vaccine (PHiD-CV) efficacy in a double-blind randomized trial (ClinicalTrials.gov: NCT00466947) against various diseases, including acute otitis media (AOM). Here, we provide further analyses. In the Panamanian subset, 7,359 children were randomized (1:1) to receive PHiD-CV or control vaccine at age 2/4/6 and 15–18 months. Of these, 2,000 had nasopharyngeal swabs collected. AOM cases were captured when parents sought medical attention for children with AOM symptoms; surveillance was enhanced approximately 2 y into the study through regular telephone calls or home visits by study personnel, who advised parents to visit the clinic if their child had AOM symptoms. Mean follow-up was 31.4 months. Clinical AOM (C-AOM) cases were assessed by physicians and confirmed by otorhinolaryngologists. Middle ear fluid samples, taken from children with C-AOM after specific informed consent, and nasopharyngeal samples were cultured for pathogen identification. For 7,359 children, 2,574 suspected AOM cases were assessed by a primary healthcare physician; 649 cases were C-AOM cases as per protocol definition. From the 503 MEF samples collected, 158 resulted in a positive culture. In the intent-to-treat cohort (7,214 children), PHiD-CV showed VE against first C-AOM (24.0% [95% CI: 8.7, 36.7]) and bacterial (B-AOM) episodes (48.0% [20.3, 66.1]) in children <24 months, which declined thereafter with age. Pre-booster VE against C-AOM was 30.7% [12.9, 44.9]; post-booster, −6.7% [−36.4, 16.6]. PHiD-CV VE was 17.7% [−6.1, 36.2] against moderate and 32.7% [−20.5, 62.4] against severe C-AOM. VE against vaccine-serotype pneumococcal NPC was 31.2% [5.3, 50.3] 3 months post-booster, and 25.6% [12.7, 36.7] across all visits. NTHi colonization rates were low and no significant reduction was observed. PHiD-CV showed efficacy against C-AOM and B-AOM in children younger than 24 months, and reduced vaccine-serotype NPC.

The global distribution and diversity of protein vaccine candidate antigens in the highly virulent Streptococcus pnuemoniae serotype 1

Serotype 1 is one of the most common causes of pneumococcal disease worldwide. Pneumococcal protein vaccines are currently being developed as an alternate intervention strategy to pneumococcal conjugate vaccines. Pre-requisites for an efficacious pneumococcal protein vaccine are universal presence and minimal variation of the target antigen in the pneumococcal population, and the capability to induce a robust human immune response. We used in silico analysis to assess the prevalence of seven protein vaccine candidates (CbpA, PcpA, PhtD, PspA, SP0148, SP1912, SP2108) among 445 serotype 1 pneumococci from 26 different countries, across four continents. CbpA (76%), PspA (68%), PhtD (28%), PcpA (11%) were not universally encoded in the study population, and would not provide full coverage against serotype 1. PcpA was widely present in the European (82%), but not in the African (2%) population. A multi-valent vaccine incorporating CbpA, PcpA, PhtD and PspA was predicted to provide coverage against 86% of the global population. SP0148, SP1912 and SP2108 were universally encoded and we further assessed their predicted amino acid, antigenic and structural variation. Multiple allelic variants of these proteins were identified, different allelic variants dominated in different continents; the observed variation was predicted to impact the antigenicity and structure of two SP0148 variants, one SP1912 variant and four SP2108 variants, however these variants were each only present in a small fraction of the global population (<2%). The vast majority of the observed variation was predicted to have no impact on the efficaciousness of a protein vaccine incorporating a single variant of SP0148, SP1912 and/or SP2108 from S. pneumoniae TIGR4. Our findings emphasise the importance of taking geographic differences into account when designing global vaccine interventions and support the continued development of SP0148, SP1912 and SP2108 as protein vaccine candidates against this important pneumococcal serotype.

Safety and Immunogenicity of Pneumococcal Conjugate Vaccine in Preterm Infants: A Meta-Analysis

OBJECTIVE

To assess the safety and immunogenicity of pneumococcal conjugate vaccine (PCVs) in preterm infants.

METHODS

In accordance with the PRISM (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement (as of May 2015), a meta-analysis was conducted to evaluate the safety and immunogenicity of PCVs in preterm infants.

RESULTS

Ten thousand nine hundred sixty full-term infants and 2131 preterm infants with 344 preterm infants of <2500 g birth weight [low-birth weight (LBW)] were included, and all the subjects were immunized with either PCV-7, PCV-10 or PCV-13 in this random-effects meta-analysis. For safety, the range of risk ratio (RRs) for local reaction was from 0.88 to 1.02 and from 0.94 to 1.24 for systematic reaction respectively. For immunogenicity, either post-primary or booster vaccination with PCV-7, PCV-10 or PCV-13, genomic mean concentration (GMC) of serotypes 4, 6B, 9 V, 19F and 23F was always less in preterm infants than in full-term infants, in which huge comparison of GMC was found in serotype 19F(SMD = -0.393, 95%CI:-0.612 ~ 0.175). After primary vaccination, the combined risk ratio (RRs) of immune response against seven common serotypes and additional serotype 1 was approximated to 1.00 with narrow 95 % confidence interval (CI) between preterm infants and full-term infants, and at least 91 % sero-conversion of two additional serotypes, 5 and 7F in two cohorts was observed. Furthermore, between very-low-birth-weight (VLBW) infants of <1500 g and 1501 ~ 2500 g, overall RRs of immune response to PCV-7 administration was 0.98 (95%CI: 0.96 ~ 1.00).

CONCLUSIONS

Preterm infants have a great tolerance to PCV-7, PCV-10 or PCV-13 vaccination. PCV-7 could elicit optimal immune response post vaccination in preterm infants, even in VLBW infants.

Etiology of acute otitis media and serotype distribution of Streptococcus pneumoniae and Haemophilus influenzae in Chilean children <5 years of age

The impact of bacterial conjugate vaccines on acute otitis media (AOM) is affected by several factors including population characteristics, bacterial etiology and vaccine conjugation method, carrier, and coverage. This study estimated the baseline etiology, distribution, and antibiotic susceptibility of bacterial serotypes that causes AOM in children aged <5 years in a public setting in Santiago, Chile.Children aged ≥3 months and <5 years referred to the physician for treatment of AOM episodes (with an onset of symptoms <72 h) were enrolled between September 2009 and September 2010. Middle ear fluid (MEF) was collected by tympanocentesis or by otorrhea for identification and serotyping of bacteria. Antibacterial susceptibility was tested using E-test (etrack: 112671).Of 160 children (mean age 27.10 ± 15.83 months) with AOM episodes, 164 MEF samples (1 episode each from 156 children; 2 episodes each from 4 children) were collected. Nearly 30% of AOM episodes occurred in children aged 12 to 23 months. Streptococcus pneumoniae (41.7% [58/139]) and Haemophilus influenzae (40.3% [56/139]) were predominant among the cultures that showed bacterial growth (85% [139/164]). All Streptococcus pneumoniae positive episodes were serotyped, 19F (21%) and 14 (17%) were the predominant serotypes; all Haemophilus influenzae strains were nontypeable. Streptococcus pneumoniae were resistant to penicillin (5%) and erythromycin (33%); Haemophilus influenzae were resistant to ampicillin (14%) and cefuroxime and cefotaxime (2% each).AOM in Chilean children is predominantly caused by Streptococcus pneumoniae and nontypeable Haemophilus influenzae. Use of a broad spectrum vaccine against these pathogens might aid the reduction of AOM in Chile.

Naturally Acquired Human Immunity to Pneumococcus Is Dependent on Antibody to Protein Antigens

Naturally acquired immunity against invasive pneumococcal disease (IPD) is thought to be dependent on anti-capsular antibody. However nasopharyngeal colonisation by Streptococcus pneumoniae also induces antibody to protein antigens that could be protective. We have used human intravenous immunoglobulin preparation (IVIG), representing natural IgG responses to S. pneumoniae, to identify the classes of antigens that are functionally relevant for immunity to IPD. IgG in IVIG recognised capsular antigen and multiple S. pneumoniae protein antigens, with highly conserved patterns between different geographical sources of pooled human IgG. Incubation of S. pneumoniae in IVIG resulted in IgG binding to the bacteria, formation of bacterial aggregates, and enhanced phagocytosis even for unencapsulated S. pneumoniae strains, demonstrating the capsule was unlikely to be the dominant protective antigen. IgG binding to S. pneumoniae incubated in IVIG was reduced after partial chemical or genetic removal of bacterial surface proteins, and increased against a Streptococcus mitis strain expressing the S. pneumoniae protein PspC. In contrast, depletion of type-specific capsular antibody from IVIG did not affect IgG binding, opsonophagocytosis, or protection by passive vaccination against IPD in murine models. These results demonstrate that naturally acquired protection against IPD largely depends on antibody to protein antigens rather than the capsule.

Streptococcus pneumoniae is a major global killer. Invasive pneumococcal disease (IPD) is the most severe form of infection. Surprisingly, the natural mechanisms of immunity to IPD in healthy individuals are unclear. The success of vaccines stimulating anti-capsular antibodies have led to the belief that the same mechanism lies behind natural protection. Using studies with pooled human immunoglobulin, we demonstrate that this is not the case and instead IgG recognising the bacterial surface proteins appears to have the dominant functional role. This finding supports efforts towards protein antigen-based vaccines, and opens the possibility of stratifying potential risk for individuals of IPD.

Burden of Pneumococcal Disease in Northern Togo before the Introduction of Pneumococcal Conjugate Vaccine

Background

S. pneumoniae is a leading cause of meningitis morbidity and mortality in the African meningitis belt, but little is known of its contribution to the burden of pneumonia in the region. We aimed to estimate the incidence of pneumococcal disease in children and adults in northern Togo, before the introduction of pneumococcal conjugate vaccine (PCV).

Methods and findings

From May 1st 2010 to April 30th 2013, we systematically enrolled all hospitalized patients meeting a case definition of suspected meningitis or clinical pneumonia, residing in Tone or Cinkasse districts, northern Togo and providing informed consent. We collected clinical data and tested biological specimens according to standardized procedures, including bacteriology and PCR testing of cerebro-spinal fluid for meningitis patients and blood cultures and whole blood lytA PCR for pneumonia patients. Chest X-rays (CXR) were interpreted using the WHO methodology. We included 404 patients with meningitis (104 <5 years of age) and 1550 with pneumonia (251 <5 years) over the study period. Of these, 78 (19%) had pneumococcal meningitis (13 <5 years), 574 (37%) had radiologically-confirmed pneumonia (83 <5 years) and 73 (5%) had culture-confirmed pneumococcal pneumonia (2 <5 years). PCV13 serotypes caused 79% (54/68) of laboratory-confirmed pneumococcal meningitis and 83% (29/35) of culture-confirmed pneumococcal pneumonia. Serotype 1 predominated in meningitis (n = 33) but not in pneumonia patients (n = 1). The incidence of pneumococcal disease was 7.5 per 100,000 among children <5 years of age and 14.8 in persons 5 years of age and above in the study area. When considering CXR-confirmed and blood PCR-positive pneumonia cases as likely pneumococcal, incidence estimates increased to 43.7 and 66.0 per 100,000 in each of these age groups, respectively. Incidence was at least 3-fold higher when we restricted the analysis to the urban area immediately around the study hospitals.

Conclusions

Our findings highlight the important role of S. pneumoniae as a meningitis and pneumonia-causing pathogen in the African meningitis belt. Pneumococcal disease incidence in our population was substantially lower than expected from global models; we hypothesize that poor access to hospital care led us to substantially underestimate the burden of disease. Surveillance is ongoing and will enable an evaluation of PCV impact, providing novel, high quality data from the region.

Racial and Ethnic Differences in Receipt of Pressure Equalization Tubes Among US Children, 2014

OBJECTIVE

Pressure equalization tube (PET) placement (also referred to as tympanostomy tube placement) is among the most common ambulatory surgical procedures performed on US children. More than 20 years ago, differences according to race/ethnicity in the national prevalence of having had PETs placed were documented. Whether these differences persist is unknown.

METHODS

We used data from the 2014 National Health Interview Survey to examine the percentage of children 0 to 17 years of age who have ever undergone PET placement. Unadjusted logistic regression with predictive margins was used to assess the relationship between having received PETs and race/ethnicity, as well as other clinical, socioeconomic, and geographic factors. Multivariable logistic regression was used to determine whether other factors could account for any observed differences according to race/ethnicity.

RESULTS

Overall, 8.9% of children 0 to 17 years of age had undergone PET surgery. By race/ethnicity, 12.6% of non-Hispanic white children received PETs, which was significantly greater than the 4.8% of non-Hispanic black, 4.4% of Hispanic, and 5.6% of non-Hispanic other/multiple race children who had this surgery (P < .001 for all comparisons). In multivariable analysis, the adjusted prevalence for non-Hispanic white children (10.8%) was greater than for non-Hispanic black (5.4%) and Hispanic (5.8%) children (P < .001 for both comparisons).

CONCLUSIONS

Nearly 9% of US children have had PETs placed. Non-Hispanic white children still have a greater prevalence of PET placement compared with non-Hispanic black and Hispanic children. These differences could not be fully explained by other demographic, clinical, socioeconomic, or geographic differences between racial/ethnic groups.

Bronchiectasis in Children: Current Concepts in Immunology and Microbiology

Bronchiectasis is a complex chronic respiratory condition traditionally characterized by chronic infection, airway inflammation, and progressive decline in lung function. Early diagnosis and intensive treatment protocols can stabilize or even improve the clinical prognosis of children with bronchiectasis. However, understanding the host immunologic mechanisms that contribute to recurrent infection and prolonged inflammation has been identified as an important area of research that would contribute substantially to effective prevention strategies for children at risk of bronchiectasis. This review will focus on the current understanding of the role of the host immune response and important pathogens in the pathogenesis of bronchiectasis (not associated with cystic fibrosis) in children.