The burden of invasive pneumococcal disease in children with underlying risk factors in North America and Europe

Control and Prevention of Invasive Pneumococcal Disease: A Current and Historical Perspective

Although significant progress has been made in reducing the incidence of invasive pneumococcal disease (IPD) in children, IPD remains a continued threat. Since the introduction of pneumococcal conjugate vaccines (PCVs), rates of IPD and non-IPD have substantially decreased. However, serotype replacement reversed some of the benefits of PCV7 and, more recently, PCV13. Several replacement serotypes are antibiotic resistant, which is a cause of concern for providers. The introduction of the higher-valency conjugate vaccines PCV15 and PCV20 is expected to provide greater serotype coverage; unfortunately, these vaccines do not include some of the recently emerged serotypes. Recommendations for the use of the 23-valent polysaccharide vaccine in high-risk populations may be modified because of the effectiveness of the newer PCVs. Pediatricians must be aware of the new vaccine strategies for the prevention of IPD and the manifestations of IPD so that prompt empirical therapy can be initiated when treatment is required. [Pediatr Ann. 2023;52(3):e96-e101.].

Invasive Pneumococcal Disease in High-risk Children: A 10-Year Retrospective Study

BACKGROUND

Despite the availability of conjugate pneumococcal vaccines, children with high-risk conditions remain vulnerable to invasive pneumococcal disease (IPD). This study sought to describe IPD prevalence, vaccination and outcomes among high-risk children.

METHODS

We used International Classification of Disease10 discharge and microbiology codes to identify patients hospitalized for IPD at a large pediatric hospital from January 1, 2009, to December 31, 2018. Patients were considered high-risk if they had: primary immunodeficiency, asplenia, transplant, active malignancy, sickle cell disease, cochlear implant, nephrotic syndrome, chronic lung disease, cerebrospinal fluid leak, HIV or used immunosuppressive therapy.

RESULTS

In total 94 high-risk patients were hospitalized for IPD. The most common high-risk conditions included malignancy (n = 33, 35%), solid-organ or bone marrow transplant (n = 17, 18%) and sickle cell disease (n = 14, 15%). Bacteremia was the most common presentation (n = 81, 86%) followed by pneumonia (n = 23, 25%) and meningitis (n = 9, 10%). No deaths occurred. Of 66 patients with known pneumococcal vaccination status, 15 (23%) were unvaccinated, and 51 (77%) received at least one dose of a pneumococcal vaccine; 20 received all four recommended pneumococcal conjugate vaccine (PCV) doses. Only three children received PPSV23. Of 20 children with no or partial (<3 doses) immunization, 70% (14) of IPD episodes were due to vaccine-preventable serotypes. Of 66 known IPD serotypes, 17% (n = 11) were covered by PCV13, 39% (n = 26) were covered by PPSV23 and 39% (n = 26) were nonvaccine serotype.

CONCLUSIONS

Despite the availability of effective pneumococcal vaccines, IPD persists among children with high-risk conditions. Improving PCV13 and PPSV23 vaccination could significantly reduce IPD; most episodes were due to vaccine-preventable serotypes in incompletely immunized patients.

Improving Pneumococcal Vaccination Rates in High-risk Children in Specialty Clinics

BACKGROUND AND OBJECTIVES

Pediatric patients with immunocompromising or certain chronic medical conditions have an increased risk of acquiring invasive pneumococcal disease (IPD). The 23-valent pneumococcal polysaccharide vaccine (PPSV23) is recommended for patients ≥2 years at high risk for IPDs. The aim of this project was to improve PPSV23 vaccination rates for children at high risk for IPD who were seen in 3 specialty clinics from ∼20% to 50% over a 12-month period.

METHODS

The project team included quality improvement champions from the divisions of rheumatology, infectious diseases, and pulmonology in addition to leaders from our population health management subsidiary. Several initiatives were implemented, starting with review of patient inclusion criteria per the vaccination recommendations, that led to the design and deployment of an automated weekly previsit planning report. Additionally, we implemented a process to stock pneumococcal vaccines and shared best practices among the divisions. We monitored improvement through times series and run charts of PPSV23 vaccination rates.

RESULTS

The initial PPSV23 vaccination rate for applicable high-risk patients was ∼20%. There was an increase in vaccination rate to ∼60%. All 3 divisions showed improvements in their individual PPSV23 vaccination rates.

CONCLUSIONS

Using quality improvement methodology, we increased PPSV23 vaccination rates in 3 pediatric specialty clinics, and this improvement was sustained. We will continue to identify best practices and actively recruit additional divisions because we have the opportunity to reach >9000 high-risk patients.

Estimating pneumococcal vaccine coverage among Australian Indigenous children and children with medically at-risk conditions using record linkage

BACKGROUND

Risk-based recommendations are common for pneumococcal vaccines but little is known about their uptake. In Australia, pneumococcal conjugate vaccine (PCV) was funded only for Aboriginal or Torres Strait Islander (Indigenous) children and those with underlying medical conditions in 2001, and then there were different booster dose recommendations depending on risk after the introduction of universal PCV vaccination in 2005.

METHODS

We measured coverage of PCV dose 3 and additional PCV and 23-valent pneumococcal polysaccharide vaccine (PPV23) doses by risk group among children born in July 2001-December 2012 in two Australian states using linked immunisation and hospitalisation data (available until December 2013). We ascertained medical risk conditions using hospitalisation diagnosis codes and Indigenous status using an established algorithm, comparing coverage for children born pre (2001-2004) and post (2005-2012) universal PCV funding.

RESULTS

Among 1.3 million children, 63,897 (4.9%) were Indigenous and 32,934 (2.5%) had at least one medically at-risk condition identified by age 6 months. For births in 2001-2004, coverage for PCV dose 3 by 1 year of age was 37% for Indigenous, 15% for medically at-risk and 11% in other children, increasing to 83%, 91% and 92%, respectively for births in 2005-2012. In children with medically at-risk conditions, PCV dose 4 coverage by 2 years was 1% for 2001-2004 births, increasing to 9% for 2005-2012 births, with PPV23 coverage by 6 years 3% in both cohorts. Among eligible Indigenous children, PPV23 coverage by 3 years was 45% for 2001-2004 births and 51% for 2005-2012 births.

CONCLUSIONS

Coverage with additional recommended booster doses was very low among children with medical conditions, and only modest among Indigenous children. If additional PCV doses are recommended for some risk groups, especially in the context of routine schedules with reduced doses (e.g. 2 + 1 and 1 + 1), measures to improve implementation will be required.

Immunization coverage among asplenic patients and strategies to increase vaccination compliance: a systematic review and meta-analysis

BACKGROUND

Asplenic or splenectomized patients have a higher risk (ranging from 10 to 50-fold) than the general population of developing an overwhelming post-splenectomy infection (OPSI). Thus, they should receive specific vaccinations to prevent bacterial infections and influenza. The aim of this meta-analysis was to estimate vaccination coverage (VC) with the recommended vaccines among splenectomized patients; strategies recommended in those studies to improve VC worldwide are considered as well.

RESEARCH DESIGN AND METHODS

Scopus, MEDLINE/PubMed, Google Scholar and ISI Web of Knowledge databases were searched. Research papers, short reports, reviews, and meta-analyses published between January 1, 2010 and July 18, 2020 were included; no geographic restrictions were included. Twenty-four studies were included in the meta-analysis.

RESULTS

For anti-pneumococcal vaccination, coverage was 55.1% (95%CI = 41.0-69.2%), for anti-Hib 48.3% (95%CI = 34.3-52.3%), for anti-meningococcal C/ACYW135 33.7% (95%CI = 23.6-43.9%), for anti-meningococcal B 13.3% (95%CI = 7.0-19.5%) and for anti-influenza 53.2% (95%CI = 22.0-84.4%). Most studies determined a lack of adherence to international guidelines by healthcare workers and suggested the need to better educate health professionals in the management of post-splenectomy patients.

CONCLUSIONS

The meta-analysis showed the suboptimal immunization coverage for the vaccines recommended for asplenic patients. Greater efforts must be made by public health professionals to increase VC in this group of patients at risk. Introducing specific prophylaxis protocols in the clinical routine seems to guarantee better immunization compliance in those patients.

Thirteen-Valent Pneumococcal Conjugate Vaccine in Children With Acute Lymphoblastic Leukemia: Protective Immunity Can Be Achieved on Completion of Treatment

BACKGROUND

Children with acute lymphoblastic leukemia (ALL) are at increased risk of developing invasive pneumococcal disease. This study describes the immunogenicity of 13-valent pneumococcal conjugate vaccine (PCV13) during and after chemotherapy.

METHODS

Children with ALL were allocated to study groups and received a single dose of PCV13: group 1, maintenance chemotherapy; group 2, end of chemotherapy; group 3, 6 months after chemotherapy. A protective vaccine response was defined as at least 10 of 12 serotypes (or >83% of serotypes with data) achieving postvaccination serotype-specific immunoglobulin G ≥0.35 µg/mL and ≥4-fold rise, compared to prevaccination at 1 and 12 months.

RESULTS

One hundred eighteen children were recruited. Only 12.8% (5/39; 95% confidence interval [CI], 4.3%-27.4%) of patients vaccinated during maintenance (group 1) achieved a protective response at 1 month postvaccination and none had a protective response at 12 months. For group 2 patients, 59.5% (22/37; 95% CI, 42.1%-75.3%) achieved a response at 1 month and 37.9% (11/29; 95% CI, 20.7%-57.7%) maintained immunity at 12 months. For group 3 patients, 56.8% (21/37; 95% CI, 39.5%-72.9%) achieved a protective response at 1 month and 43.3% (13/30; 95% CI, 25.5%-62.6%) maintained immunity at 12 months.

CONCLUSIONS

This study demonstrated that the earliest time point at which protective immunity can be achieved in children with ALL is on completion of chemotherapy. This is earlier than current recommendations and may improve protection during a period when children are most susceptible to infection.

CLINICAL TRIALS REGISTRATION

EudraCT 2009-011587-11.

Prevalence of Immunodeficiency in Children With Invasive Pneumococcal Disease in the Pneumococcal Vaccine Era: A Systematic Review

IMPORTANCE

Despite increasing access to vaccination, invasive pneumococcal disease (IPD) is responsible for approximately 826 000 deaths worldwide in children younger than 5 years each year. To allow early identification and prevention, an improved understanding of risk factors for IPD is needed.

OBJECTIVES

To review the literature on the prevalence of primary immunodeficiency (PID) in children younger than 18 years presenting with IPD without another predisposing condition and to inform guidelines for immunologic evaluation after the first episode of IPD based on published evidence.

EVIDENCE REVIEW

A literature search of PubMed, Embase (inception [1974] to February 28, 2019), and MEDLINE (inception [1946] to February 28, 2019) was conducted using the terms Streptococcus pneumonia, Streptococcus pneumoniae, pneumococcal infection, Streptococcus infection, pneumococcal meningitis, immunodeficiency, immune response, immunocompromised, susceptib*, precursor, predispose*, recurren*, newborn, neonat*, infan*, toddler, child, preschooler, adolescen*, and pediatric. Publications reporting original data on immunodeficiency in children with microbiologically confirmed primary or recurrent IPD were included. Strength of clinical data was graded according to the 5-point scale of the Oxford Centre for Evidence-Based Medicine.

FINDINGS

In 6022 unique children with primary IPD, 5 of 393 (1.3%) to 17 of 162 (10.5%) of all children and 14 of 53 (26.4%) of those older than 2 years had a PID identified. Higher rates of PID, up to 10 of 15 (66.7%), were found in children with recurrent IPD. Antibody deficiency was the most common immunodeficiency, followed by complement deficiency, asplenia, and rarer defects in T-cell signaling. The site of infection was a key indicator for the risk of underlying PID, with the greatest risk of PID in children with meningitis or complicated pneumonia.

CONCLUSIONS AND RELEVANCE

Results of this study suggest that invasive pneumococcal disease, and particularly recurrent IPD, is an important marker of underlying PID in children without other risk factors. The findings also suggest that children older than 2 years with pneumococcal meningitis or complicated pneumonia and all children with recurrent IPD should be referred for an immune evaluation.

TRIAL REGISTRATION

PROSPERO identifier: CRD42017075978.

Long-term Vaccine Impact on Invasive Pneumococcal Disease Among Children With Significant Comorbidities in a Large Australian Birth Cohort

BACKGROUND

Little is known about long-term invasive pneumococcal disease (IPD) incidence in children with risk factors (RFs) in populations with high coverage pneumococcal conjugate vaccine (PCV) programs. We measured IPD burden and changes with PCV use in children by RF status.

METHODS

A retrospective cohort of all live births in 2001-2012 in New South Wales, Australia was linked to IPD, hospitalization and death data. RFs were identified from International Classification of Diseases codes in linked hospitalizations. For each RF adjusted hazard ratios (aHRs, using Cox models), population attributable fractions (PAFs) and changes post-PCV relative to baseline for IPD were calculated.

RESULTS

One-thousand two-hundred fifty-one IPD cases occurred in ~1.1 million children in 12-year study cohort. The 75,404 children (6.8% of cohort) with RFs accounted for 255 (20.4%) IPD cases [rate (per 100,000 person-years) of 61 compared with 14 in no RFs]. Asthma was most common RF (n = 41,074; 3.6%) but highest IPD risk was in 2452 children (0.2%) with immunosuppression, splenic dysfunction or breach in cerebrospinal fluid barrier (aHR~20; PAF 0.7-1.8%) versus asthma (aHR 5.3; PAF 14.8%). Compared with 2001-2004 birth cohort (baseline), IPD incidence in PCV-eligible 2009-2012 birth cohort was 78% (95% confidence interval: -72% to -82%) less in children without RFs. IPD declined nonsignificantly (13%; 95% confidence interval: -70% to +138%) in highest IPD risk group, but by 67% (-43% to -82%) in children with other RFs.

CONCLUSIONS

By 8 years of universal PCV, IPD incidence reduced significantly in all children except in the 0.2% at highest risk, for whom antibiotic prophylaxis and additional vaccine doses are recommended but compliance and effectiveness remain uncertain.

[Clinical characteristics and drug sensitivity in children with invasive pneumococcal disease: a multicenter study]

OBJECTIVE

To study the clinical characteristics, drug sensitivity of isolated strains, and risk factors of drug resistance in children with invasive pneumococcal disease (IPD).

METHODS

The clinical characteristics and drug sensitivity of the isolated strains of 246 hospitalized children with IPD in nine grade A tertiary children's hospitals from January 2016 to June 2018 were analyzed.

RESULTS

Of the 246 children with IPD, there were 122 males and 124 females. Their ages ranged from 1 day to 14 years, and among them, 68 (27.6%) patients were less than 1 year old, 54 (22.0%) patients were 1 to 2 years old, 97 (39.4%) patients were 2 to 5 years old, and 27 (11.0%) patients were 5 to 14 years old. Pneumonia with sepsis was the most common infection type (58.5%, 144/246), followed by bloodstream infection without focus (19.9%, 49/246) and meningitis (15.0%, 37/246). Forty-nine (19.9%) patients had underlying diseases, and 160 (65.0%) had various risk factors for drug resistance. The isolated Streptococcus pneumoniae strains were 100% sensitive to vancomycin, linezolid, moxifloxacin, and levofloxacin, 90% sensitive to ertapenem, ofloxacin, and ceftriaxone, but had a low sensitivity to erythromycin (4.2%), clindamycin (7.9%), and tetracycline (6.3%).

CONCLUSIONS

IPD is more common in children under 5 years old, especially in those under 2 years old. Some children with IPD have underlying diseases, and most of the patients have various risk factors for drug resistance. Pneumonia with sepsis is the most common infection type. The isolated Streptococcus pneumoniae strains are highly sensitive to vancomycin, linezolid, moxifloxacin, levofloxacin, ertapenem, and ceftriaxone in children with IPD.

[Clinical characteristics and drug sensitivity in children with invasive pneumococcal disease: a multicenter study]

OBJECTIVE

To study the clinical characteristics, drug sensitivity of isolated strains, and risk factors of drug resistance in children with invasive pneumococcal disease (IPD).

METHODS

The clinical characteristics and drug sensitivity of the isolated strains of 246 hospitalized children with IPD in nine grade A tertiary children's hospitals from January 2016 to June 2018 were analyzed.

RESULTS

Of the 246 children with IPD, there were 122 males and 124 females. Their ages ranged from 1 day to 14 years, and among them, 68 (27.6%) patients were less than 1 year old, 54 (22.0%) patients were 1 to 2 years old, 97 (39.4%) patients were 2 to 5 years old, and 27 (11.0%) patients were 5 to 14 years old. Pneumonia with sepsis was the most common infection type (58.5%, 144/246), followed by bloodstream infection without focus (19.9%, 49/246) and meningitis (15.0%, 37/246). Forty-nine (19.9%) patients had underlying diseases, and 160 (65.0%) had various risk factors for drug resistance. The isolated Streptococcus pneumoniae strains were 100% sensitive to vancomycin, linezolid, moxifloxacin, and levofloxacin, 90% sensitive to ertapenem, ofloxacin, and ceftriaxone, but had a low sensitivity to erythromycin (4.2%), clindamycin (7.9%), and tetracycline (6.3%).

CONCLUSIONS

IPD is more common in children under 5 years old, especially in those under 2 years old. Some children with IPD have underlying diseases, and most of the patients have various risk factors for drug resistance. Pneumonia with sepsis is the most common infection type. The isolated Streptococcus pneumoniae strains are highly sensitive to vancomycin, linezolid, moxifloxacin, levofloxacin, ertapenem, and ceftriaxone in children with IPD.

Prevalence of Nasopharyngeal Carriage, Serotype Distribution, and Antimicrobial Resistance of Streptococcus pneumoniae among Children with Chronic Diseases

The aim of this study was to evaluate the prevalence of nasopharyngeal (NP) carriage and the serotype distribution and antimicrobial resistance of Streptococcus pneumoniae in children with chronic diseases, which predisposes them to invasive pneumococcal disease in comparison with that in healthy children. A cross-sectional prevalence study was performed between February 2015 and February 2016 in Istanbul, Turkey. We enrolled 1,024 children with chronic diseases and 394 healthy children aged 0-18 years. The overall prevalence of S. pneumoniae NP (SPNP) carriage was 9.8%, with 8.4% in healthy children and 10.3% in children with chronic diseases. The prevalence rates of SPNP carriage were 17.5%, 13.5%, 10.5%, 9.3%, 8.6%, 8.6%, 8%, 6.7%, and 4%, respectively, in each of the following risk groups: primary immunodeficiency, asthma, chronic renal failure, congenital heart disease, chronic lung disease, leukemia, nephrotic syndrome, solid organ tumors, and type 1 diabetes mellitus. In the multivariate analysis, a history of otitis media within the last year, a history of pneumonia within the last year, and more than one sibling under 8 years of age were found to be independent risk factors for SPNP carriage.

Preterm Children Have Higher Risk Than Full-term Children of Invasive Pneumococcal Disease During the First 2 Years of Life

BACKGROUND

A few previous studies have reported an increased risk of invasive pneumococcal disease (IPD) in children born preterm, but this has not been investigated in a cohort study. The impact of 7-valent pneumococcal conjugate vaccine (PCV7) on IPD incidence rates in preterm children is unknown.

METHODS

Data from the Medical Birth Registry of Norway (2002-2010) were linked to other national registries. In total, 628,138 children were included in our study and followed until 2 years of age. Incidence rate ratios (IRRs) and confidence intervals (CIs) were estimated with Poisson regression.

RESULTS

We identified 411 cases of IPD. We observed higher rates of IPD in preterm than in full-term children for the intervals 0-23, 0-5 and 6-23 months of age, IRRs = 1.83 (95 % CI: 1.36-2.47), 2.95 (95% CI: 1.44-6.06) and 1.69 (95% CI: 1.22-2.34), respectively. The risk for IPD was reduced in the PCV7-period (2007-2010) compared with that of the pre PCV7-period (2002-2005) for children 6-23 months of age, IRRs = 0.20 (95% CI: 0.08-0.53) for preterm children and 0.28 (95% CI: 0.21-0.38) for full-term children, but not for those 0-5 months of age, IRRs = 1.94 (95% CI: 0.48-7.80) and 0.71 (95% CI: 0.38-1.33).

CONCLUSIONS

Preterm children had an increased risk of IPD. After introduction of PCV7, the rate of IPD was reduced among preterm and full-term children from 6 months of age.

Comparative incidence dynamics and serotypes of meningitis, bacteremic pneumonia and other-IPD in young children in the PCV era: Insights from Israeli surveillance studies

INTRODUCTION

Widespread introduction of pneumococcal conjugated vaccines (PCVs) impacted on invasive pneumococcal disease (IPD). However, IPD reduction may not be similar in all outcomes within IPD. We assessed PCV7/PCV13 impact on pneumococcal meningitis, bacteremic pneumonia (BP) and other (non-meningitis, non-pneumonia) IPD episodes in children <5years in Israel.

METHODS

A prospective, population-based, active nationwide surveillance. All pneumococcal invasive episodes with positive blood/CSF cultures, July 2000 through June 2016, were included. Three sub-periods were defined: pre-PCV (2000-2008), PCV7 (2009-2011) and PCV13 (2014-2016). Incidence rate ratios (IRRs) were calculated.

RESULTS

Overall, 4321 episodes were recorded; 456 (10.6%) meningitis, 1478 (34.2%) pneumonia and 2387 (55.2%) other-IPD. In the pre-PCV period, proportion of serotypes in PCV13, but not in PCV7 (mainly serotypes 1, 5 and 19A) was higher in BP (43.3%) compared with other-IPD episodes (32.8%, p<0.001) and similar to that of meningitis (37.6%, p=0.1). The proportion of episodes in children <12months was higher in meningitis (52.1%) compared with pneumonia (23.2%) and other-IPD episodes (39.5%; p<0.001 for both). The declines of the 3 entities were not similar; Meningitis rate non-significantly declined by 24% (IRR=0.76; 95% CI 0.57-1.01), while BP and other-IPD rates significantly declined by 57% and 70%, respectively. In contrast to other entities, BP did not decline significantly after PCV7 introduction but started to decline only after PCV13 introduction. Rates of meningitis, pneumonia and other-IPD caused by PCV13-serotypes (VT13) substantially declined by 88%, 95% and 97%, respectively, comparing PCV13 and the pre-PCV periods. However, diseases caused by non-VT13 increased by 256%, 302% in meningitis and pneumonia, respectively, but only 116% in other-IPD.

CONCLUSIONS

Following PCV7/PCV13 introduction, rates of episodes caused by VT13 were substantially reduced in all 3 groups. However, differences in age distribution, serotype replacement and specific serotype decrease suggest different pathogenesis and host susceptibility between the 3 entities.

Streptococcus pneumoniae pharyngeal colonization in school-age children and adolescents with cancer

Patients with cancer, particularly those with hematologic malignancies, are at an increased risk of invasive pneumococcal disease (IPD) and they are included in the list of subjects for whom pneumococcal vaccination is recommended. The main aim of this study was to evaluate Streptococcus pneumoniae colonization in school-aged children and adolescents with cancer to determine the potential protective efficacy of 13-valent pneumococcal conjugate vaccine (PCV13). An oropharyngeal swab was obtained from 277 patients (age range 6-17 years) with cancer during routine clinical visits and analyzed for S. pneumoniae using real-time polymerase chain reaction. S. pneumoniae was identified in 52 patients (18.8%), including 47/235 (20.0%) with hematologic malignancies and 5/42 (11.9%) with solid tumors. Colonization declined significantly with an increase in age (odds ratio [OR] 0.34, 95% confidence interval [CI] 0.16-0.71, and OR 0.30, 95% CI 0.11-0.82 in children aged 10-14 and ≥15 years, respectively, as compared to those <10 years). Carriage was more common among patients with leukemia or lymphoma than in children with solid tumors. Co-trimoxazole prophylaxis was significantly associated with reduced pneumococcal carriage (OR 0.41, 95% CI 0.19-0.89). A total of 15/58 (25.9%) and 26/216 (12.0%) children were colonized by PCV13 serotypes among cancer patients previously vaccinated and not vaccinated with 7-valent pneumococcal conjugate vaccine (PCV7), respectively. In conclusion, this study indicates that children and adolescents with cancer are frequently colonized by S. pneumoniae. Because most of the carried serotypes are included in PCV13, this vaccine is presently the best solution to reduce the risk of IPD in these patients.

Comparative impact of pneumococcal conjugate vaccines on pneumococcal meningitis according to underlying conditions

BACKGROUND

Several underlying conditions increase the risk of pneumococcal meningitis (PM) in childhood. Patients with these diseases are initially considered as an important target of pneumococcal conjugate vaccines (PCVs). Limited data are available for PM in children with underlying conditions. To understand the benefits of PCV7 followed by PCV13 in this vulnerable population, we analyzed the data for a large cohort of pediatric patients with PM in France from 2001 to 2014.

METHODS

We conducted hospital-based active surveillance with 227 pediatric wards working with 168 microbiology departments throughout France. Standardized inclusion criteria for PM were used and data were analyzed by a pre-PCV7, post-PCV7 and post-PCV13 period.

RESULTS

From 2001 to 2014, among the 1582 cases of PM, 62.5% were reported in children less than 2years old. Underlying conditions (n=255, 16.1%) accounted for 7.3% of the cases in these young children versus 30.8% for children ⩾2-18years old (p<0.001). After PCV13 implementation, PM cases decreased by 44.0% from 2009 to 2014, mainly in children without underlying conditions. Though the number of children with underlying conditions remained stable, their proportion among overall PM cases increased by 79.1%. Among children with underlying conditions, PCV7 serotypes, 6 additional PCV13 serotypes, additional 11 serotypes in PPV23 and other serotypes accounted for 24.5%, 14.7%, 25.0% and 35.8%, respectively (p<0.001). After PCV13 implementation, 50.0% of PM cases with underlying conditions and 37.9% without underlying conditions were caused by serotypes included in neither PCV13 nor PPV23.

CONCLUSION

Besides the reduced numbers of PM, its profile has changed, with an increase in cases in proportion of children with underlying conditions accompanied by a striking change in serotype distribution. This underlines the importance of detecting underlying conditions in children with PM in the PCV13 era.

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 vaccination: what have we learnt so far and what can we expect in the future?

Individuals <2 years and ≥50 years of age, as well as those with other specific risk factors, are especially vulnerable to invasive pneumococcal disease (IPD). Conjugate vaccines have been developed against encapsulated bacteria such as Streptococcus pneumoniae to provide improved immune responses. The 7-valent pneumococcal conjugate vaccine (PCV7) has significantly reduced the burden of vaccine-type pneumococcal diseases in children, including invasive disease and pneumonia and acute otitis media. There have also been significant declines in antimicrobial resistance in 7-valent vaccine serotypes and carriage of S. pneumoniae in the post-PCV7 era. Two to three years after the introduction of PCV13, there is emerging, global evidence of a reduced burden of pneumococcal diseases in children, including declines in IPD (UK and Germany) and nasopharyngeal carriage of PCV13 serotypes (Portugal and France). The functional immunogenicity of PCV13 in individuals ≥50 years of age has been demonstrated in clinical trials in comparison with the 23-valent pneumococcal polysaccharide vaccine and for children and adults 6 to 49 years of age. Between 2011 and 2013, PCV13 received market authorisation by the European Medicines Agency (EMA) for these additional age groups and is now available in Europe for the prevention of pneumococcal disease in all age groups.

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.