Trends of pneumococcal meningitis in children after introduction of the 13-valent pneumococcal conjugate vaccine in France

Global Case Fatality of Bacterial Meningitis During an 80-Year Period: A Systematic Review and Meta-Analysis

Importance

The impact of vaccination, antibiotics, and anti-inflammatory treatment on pathogen distribution and outcome of bacterial meningitis over the past century is uncertain.

Objective

To describe worldwide pathogen distribution and case fatality ratios of community-acquired bacterial meningitis.

Data Sources

Google Scholar and MEDLINE were searched in January 2022 using the search terms bacterial meningitis and mortality.

Study Selection

Included studies reported at least 10 patients with bacterial meningitis and survival status. Studies that selected participants by a specific risk factor, had a mean observation period before 1940, or had more than 10% of patients with health care-associated meningitis, tuberculous meningitis, or missing outcome were excluded.

Data Extraction and Synthesis

Data were extracted by 1 author and verified by a second author. The study followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. Random-effects models stratified by age (ie, neonates, children, adults), Human Development Index (ie, low-income or high-income countries), and decade and meta-regression using the study period's year as an estimator variable were used.

Main Outcome and Measure

Case fatality ratios of bacterial meningitis.

Results

This review included 371 studies performed in 108 countries from January 1, 1935, to December 31, 2019, describing 157 656 episodes. Of the 33 295 episodes for which the patients' sex was reported, 13 452 (40%) occurred in females. Causative pathogens were reported in 104 598 episodes with Neisseria meningitidis in 26 344 (25%) episodes, Streptococcus pneumoniae in 26 035 (25%) episodes, Haemophilus influenzae in 22 722 (22%), other bacteria in 19 161 (18%) episodes, and unidentified pathogen in 10 336 (10%) episodes. The overall case fatality ratio was 18% (95% CI, 16%-19%), decreasing from 32% (95% CI, 24%-40%) before 1961 to 15% (95% CI, 12%-19%) after 2010. It was highest in meningitis caused by Listeria monocytogenes at 27% (95% CI, 24%-31%) and pneumococci at 24% (95% CI, 22%-26%), compared with meningitis caused by meningococci at 9% (95% CI, 8%-10%) or H influenzae at 11% (95% CI, 10%-13%). Meta-regression showed decreasing case fatality ratios overall and stratified by S pneumoniae, Escherichia coli, or Streptococcus agalactiae (P < .001).

Conclusions and Relevance

In this meta-analysis with meta-regression, declining case fatality ratios of community-acquired bacterial meningitis throughout the last century were observed, but a high burden of disease remained.

Cost-effectiveness analysis of PCV20 to prevent pneumococcal disease in the Canadian pediatric population

This study assessed the cost-effectiveness of the 20-valent pneumococcal conjugate vaccine (PCV20) in Canadian infants aged <2 years versus the standard of care (SoC), a 13-valent pneumococcal conjugate vaccine (PCV13), or a potential 15-valent pneumococcal conjugate vaccine (PCV15). A decision-analytic Markov model was developed to compare PCV20 with PCV13 or PCV15 in a 2 + 1 schedule over 10 years. Vaccine effect estimates (direct and indirect) across all ages were informed by PCV13 clinical effectiveness and impact studies as well as PCV7 efficacy studies. Epidemiologic, clinical, health state utilities, utility decrements, cost per event, and list price data were from Canadian sources where available. Clinical and economic outcomes related to invasive pneumococcal disease (IPD), hospitalized and non-hospitalized pneumonia, and simple and complex otitis media (OM) were calculated for each strategy. Cost-effectiveness was evaluated from the publicly funded healthcare system perspective. Over 10 years, PCV20 versus PCV13 was estimated to avert over 11,000 IPD cases, 316,000 hospitalized and non-hospitalized pneumonia cases, 335,000 simple and complex OM cases, and 15,000 deaths, resulting in cost savings of over 3.2 billion Canadian dollars (CAD) and 47,000 more quality-adjusted life years (i.e. dominant strategy). Compared with PCV15, PCV20 was estimated to result in over 1.4 billion CAD in cost savings and 21,000 more QALYs (i.e. dominant strategy). PCV20 was dominant over both PCV13 and PCV15. Given broader serotype coverage, substantial incremental benefits and cost-savings, PCV20 should be considered as a replacement for the SoC in the publicly funded Canadian infant immunization program.

Addition of daptomycin for the treatment of pneumococcal meningitis: protocol for the AddaMAP study

BACKGROUND

The leading cause of acute bacterial meningitis in adults is Streptococcus pneumoniae. This infection is associated with high rates of mortality and morbidity related, among other factors, to the excessive host response to the pneumococcal lysis. Experimental in vitro and in vivo data show that the combination of corticosteroids/third-generation cephalosporins and the non-lytic antibiotic, daptomycin, has synergistic effects with (1) a rapid cerebrospinal fluid sterilisation, (2) less brain damages and (3) less loss of cognitive performances. Despite these encouraging results, daptomycin has never been evaluated in adult patients with pneumococcal meningitis.

METHODS AND ANALYSIS

The AddaMAP trial is a phase II, open-label, Simon's two-stage, multicentre trial that has been designed to assess the efficacy and safety of adding daptomycin (10 mg/kg/d for 8 days) to the recommended treatment (corticosteroids+third generation cephalosporin) in adults with confirmed pneumococcal meningitis. The main endpoint is the disability-free survival (defined as modified Rankin Scale mRS≤2) at day 30. Secondary outcomes are overall mortality, disability at D30 and D90 (mRS, Glasgow Coma Scale and Glasgow Outcome Scales, mini-mental score), hearing loss (Hearing Handicap Inventory Test at D30 and D90, routine audiometric test and Hearing-it test at D30), and quality of life (12-item Short Form Survey and WHO QOL BREF). Seventy-two analysable patients are required.

ETHICS AND DISSEMINATION

The study protocol was approved by the Institutional Review Board of the IDF 1 of the ethics committee on 16 January 2018, and authorisation was obtained from the Agence Nationale de Securité des Médicaments et des Produits de Santé on 22 September 2017. The results will be submitted for publication in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

NCT03480191.

Recognition and Outcomes of Pneumococcal Meningitis in 2 Tertiary Pediatric Hospitals Since the Introduction of the 13-Valent Pneumococcal Conjugate Vaccine

OBJECTIVES

The aims of the study were to analyze the demographics, presentation, laboratory findings, and complications of pediatric Streptococcus pneumoniae meningitis since the introduction of the 13-valent pneumococcal conjugate vaccine, to improve recognition, and to minimize patient morbidity and mortality.

METHODS

This study used a retrospective analysis of pediatric pneumococcal meningitis cases at 2 tertiary healthcare systems in the Southeastern United States from 2010 to 2018.

RESULTS

We describe 21 cases of pneumococcal meningitis. All patients presented with fever, 95% had altered mental status by history or examination, and 48% had meningeal signs. Forty-three percent had seen another provider within 48 hours of admission. Forty-eight percent had delay in lumbar puncture (LP) of more than 6 hours after antibiotic administration, decreasing rates of positive cerebrospinal fluid cultures from 100% to 40% (P < 0.001). Decision to delay LP was due to either low suspicion for meningitis (n = 4) or clinical instability (n = 6) and was associated with lower rates of meningeal signs (P = 0.014) and higher rates of altered mental status on examination (P = 0.031). Fourteen patients (67%) were up-to-date on pneumococcal immunization. Serotypes were determined in 16 cases, with 2 patients (13%) immunized against the strain that infected them. Primary outcomes included seizures (48%), hearing loss (48%), cranial nerve palsy (33%), and death (5%). Delay in LP with low suspicion for meningitis was associated with longer hospital length of stay approaching statistical significance (P = 0.053).

CONCLUSIONS

Pneumococcal meningitis remains a relevant and potentially fatal disease despite widespread use of 13-valent pneumococcal conjugate vaccine. Its diagnosis is often delayed during interactions with physicians, which may put patients at increased risk for poor clinical outcomes.

Divergent serotype replacement trends and increasing diversity in pneumococcal disease in high income settings reduce the benefit of expanding vaccine valency

Streptococcus pneumoniae is a significant cause of otitis media, pneumonia, and meningitis. Only seven of the approximately 100 serotypes were initially included in the pneumococcal polysaccharide conjugate vaccine (PCV) in 2000 before it was expanded in subsequent years. Although the invasive pneumococcal disease (IPD) incidence due to vaccine serotypes (VT) has declined, partial replacement by non-vaccine serotypes (NVT) was observed following widespread vaccine uptake. We conducted a trend analysis assembling the available evidence for PCV impact on European, North American and Australian national IPD. Significant effectiveness against VT IPD in infants was observed, although the impact on national IPD incidence varied internationally due to serotype replacement. Currently, NVT serotypes 8, 9N, 15A and 23B are increasing in the countries assessed, although a variety of other NVTs are affecting each country and age group. Despite these common emerging serotypes, there has not been a dominant IPD serotype post-vaccination as there was pre-vaccination (serotype 14) or post-PCV7 (serotype 19A), suggesting that future vaccines with additional serotypes will be less effective at targeting and reducing IPD in global populations than previous PCVs. The rise of diverse NVTs in all settings’ top-ranked IPD-causing serotypes emphasizes the urgent need for surveillance data on serotype distribution and serotype-specific invasiveness post-vaccination to facilitate decision making concerning both expanding current vaccination programmes and increasing vaccine valency.

New Strategy Is Needed to Prevent Pneumococcal Meningitis

BACKGROUND

Polysaccharide conjugate vaccines (PCVs) target the pneumococcal capsular types that most commonly cause fatal pneumonia and sepsis. Because these types were eliminated by the vaccines, it became apparent that in immunized populations, most invasive pneumococcal diseases, including bacteremia, sepsis and complicated pneumonia, were greatly reduced. However, the protective effects of PCVs against another invasive disease, meningitis, has shown much less or no decrease in disease incidence.

METHODS

References were identified through searches of PubMed for articles published from January 1930 to the present by use of specific search terms. Relevant articles were also identified through searches in Google and Google Scholar. Relevant references cited in those articles were also reviewed.

RESULTS

Even in the presence of the PCVs, meningitis rates in children have been reported globally to be as high as 13 per 100,000 annually. Widespread use of vaccines resulted in the emergence of a broad diversity of replacement non-PCV type strains. These strains generally failed to cause sepsis, but caused meningitis of comparable severity and levels similar to, or in excess of, prior pneumococcal meningitis rates. This is probably because these non-PCV type strains do not survive well in the blood, therefore possibly entering the brain through nonhematogenous routes.

CONCLUSIONS

Because virtually all cases of pneumococcal meningitis lead to either permanent neurologic sequelae or death, it would be well worth the effort to develop a new vaccine capable of preventing pneumococcal meningitis regardless of capsular type. Such a vaccine would need to protect against colonization with most, if not all, pneumococci.

Evolution of Different Bacterial Mningoencephalitis: Series of Case Presentations and Literature Review

Bacterial meningitis is one of the most important medical emergencies, a life-threatening condition that leads to death in all the cases in untreated patients. In infants and young children, especially under 5 years old, the most encountered and severe forms are caused by Streptococcus pneumoniae, Neisseria meningitidis and Hemophilus influenzae type b. The risk of neurological impairment after an acute episode of bacterial meningitis is relatively high. Worldwide, prevention through vaccination decreased dramatically incidence and mortality related to these disease. In Romania vaccination for Neisseria meningitides is optional available for just 6 months, vaccination for Streptococcus pneumoniae by one year, and for Haemophylus influenzae type B is available over 10 years.

We present evolution of a series of three cases with different bacterial meningoencephalitis with severe evolution and prolonged hospitalization. All these cases were reported in unvaccinated children for germs that cause meningitis.

Pneumococcal Vaccines

Streptococcus pneumoniae is a Gram-Positive pathogen that is a major causative agent of pneumonia, otitis media, sepsis and meningitis across the world. The World Health Organization estimates that globally over 500,000 children are killed each year by this pathogen. Vaccines offer the best protection against S. pneumoniae infections. The current polysaccharide conjugate vaccines have been very effective in reducing rates of invasive pneumococcal disease caused by vaccine type strains. However, the effectiveness of these vaccines have been somewhat diminished by the increasing numbers of cases of invasive disease caused by non-vaccine type strains, a phenomenon known as serotype replacement. Since, there are currently at least 98 known serotypes of S. pneumoniae, it may become cumbersome and expensive to add many additional serotypes to the current 13-valent vaccine, to circumvent the effect of serotype replacement. Hence, alternative serotype independent strategies, such as vaccination with highly cross-reactive pneumococcal protein antigens, should continue to be investigated to address this problem. This chapter provides a comprehensive discussion of pneumococcal vaccines past and present, protein antigens that are currently under investigation as vaccine candidates, and other alternatives, such as the pneumococcal whole cell vaccine, that may be successful in reducing current rates of disease caused by S. pneumoniae.

The impact of routine childhood immunization with higher-valent pneumococcal conjugate vaccines on antimicrobial-resistant pneumococcal diseases and carriage: a systematic literature review

Introduction: The introduction of 7-valent pneumococcal conjugate vaccine (PCV7) in childhood immunization programs reduced antimicrobial-resistant pneumococcal infections by vaccine serotypes. However, emerging antimicrobial-resistant non-vaccine serotypes, particularly serotype 19A, attenuated the overall effect. In 2010, higher-valent PCVs became available containing serotypes that are prone to become antimicrobial-resistant, like serotype 7F in PCV10 and PCV13, and serotype 19A in PCV13.Areas covered: This review evaluated literature published between June 1, 2008 and June 1, 2017 reporting on the effect of PCV10 or PCV13 implementation in routine infant immunization schedules on antimicrobial-resistant invasive pneumococcal disease (IPD), otitis media (OM), and nasopharyngeal carriage (NPC) in children and adults.Expert opinion: In countries with relatively high prior pneumococcal antimicrobial resistance (AMR), PCV13 childhood vaccination programs have reduced antimicrobial-resistant IPD, OM, and NPC in children and IPD in adults. The effectiveness of PCV13 against serotype 19A is likely an important contributing factor. Only few studies have documented the impact of PCV10 on AMR. Multiple factors may influence observed decreases in pneumococcal AMR including antimicrobial stewardship, case definition, time since PCV10/13 introduction, and pre-PCV10/13 AMR levels. This review emphasizes the importance of including impact on AMR when evaluating the full public health of pneumococcal vaccination programs.

Recurrent Pneumococcal Meningitis in Children: A Multicenter Case-control Study

BACKGROUND

Pneumococcal meningitis (PM) is a serious disease that can rarely recur at a later time after the initial episode.

METHODS

A retrospective multicenter case-control study was conducted with data for children 18 years of age or younger obtained from the National Observatory of Bacterial Meningitis in Children between January 2001 and September 2015. Cases were all patients with RPM. Each case was matched with 2 randomized controls with a single PM episode in the year of the first episode of PM in the case and born the same year. Case and control data were compared.

RESULTS

Among the 1634 PM episodes in children 18 years of age or younger, 24 (1.5%) children had RPM. RPM cases were significantly less frequent than single PM cases in winter (27% vs. 48%; P=0.03) and showed significantly less concomitant ear, nose and throat infections when considering the first episode (30% vs. 56%, P = 0.04) and all episodes (28% vs. 56%, P < 0.01). Cerebrospinal fluid leakage was frequent in RPM cases versus controls (83% vs. 10%, P < 0.01), including 25% discovered after the third PM episode. Immune deficiency was absent in cases and present in 15% of controls. Cases and controls did not differ in death rate or neurologic outcome.

CONCLUSIONS

RPM is rare in children. Cerebrospinal fluid leakage must be considered.

Association of Pneumococcal Conjugate Vaccine Coverage With Pneumococcal Meningitis: An Analysis of French Administrative Areas, 2001-2016

Geographic variations of invasive pneumococcal disease incidence and serotype distributions were observed after pneumococcal conjugate vaccine introduction at regional levels and among French administrative areas. The variations could be related to regional vaccine coverage (VC) variations that might have direct consequences for vaccination-policy impact on invasive pneumococcal disease, particularly pneumococcal meningitis (PM) incidence. We assessed vaccine impact from 2001 to 2016 in France by estimating the contribution of regional VC differences to variations of annual local PM incidence. Using a mixed-effect Poisson model, we showed that, despite some variations of VC among administrative areas, vaccine impact on vaccine-serotype PM was homogeneously confirmed among administrative areas. Compared with the prevaccine era, the cumulative VC impact on vaccine serotypes led, in 2016, to PM reductions ranging among regions from 87% (25th percentile) to 91% (75th percentile) for 7-valent pneumococcal conjugate vaccine serotypes and from 58% to 63% for the 6 additional 13-valent pneumococcal conjugate vaccine serotypes. Nonvaccine-serotype PM increases from the prevaccine era ranged among areas from 98% to 127%. By taking into account the cumulative impact of growing VC and VC differences, our analyses confirmed high vaccine impact on vaccine-serotype PM case rates and suggest that VC variations cannot explain PM administrative area differences.

Prognostic factors in pediatric pneumococcal meningitis patients in mainland China: a retrospective multicenter study

Background: Prognosis of pneumococcal meningitis (PM) remains very poor, especially in less developed countries. Currently, few multi-centric studies on pediatric PM have been reported in mainland China.

Objectives: This study aimed to explore the correlation of clinical and laboratory findings with complications and prognosis in pediatric PM.

Methods: The pediatric PM patients were retrospectively recruited from ten pediatric tertiary hospitals across China between January 2013 and June 2018. Clinical, biochemical, and microbiological data and follow-up information were collected. Predictive factors for complications and prognostic factors for overall survival (OS) and sequelae-free survival (SFS) were analyzed.

Results: A total of 132 pediatric PM patients were included. Seventy-one patients had complications, 25 patients died, and 39 patients had neurological sequelae. Multivariate logistic regression suggested that age less than 28 months (adjusted OR=2.654, 95%CI=1.067–6.600, P=0.036) and lower white blood cells in blood (aOR=3.169, 95%CI=1.395–7.202, P=0.006) were associated with high risk of complications. Multivariate Cox’s proportional hazard regression suggested that age less than 28 months (aHR=6.479, 95%CI=1.153–36.404, P=0.034), coma (aHR=9.808, 95%CI=2.802–34.323, P=0.000), and non-adjuvant steroid therapy (aHR=4.768 95%CI=1.946–11.678, P=0.001) were independent prognostic factors for poor OS; coma (aHR=5.841, 95%CI=2.652–12.864, P=0.000), septic shock on admission (aHR=2.949, 95%CI=1.049–8.290, P=0.040), and lower glucose level in cerebrospinal fluid (CSF) (aHR=2.523, 95%CI=1.336–4.765, P=0.004) were independent prognostic factors for poor SFS.

Conclusion: Age, coma, and adjuvant steroid therapy were independent factors for OS, while coma, septic shock on admission, and lower glucose level in CSF were independent factors for SFS in pediatric PM patients. These factors might be used to identify PM patients with poor prognosis and guide individual treatment.

High Concentration of C-Reactive Protein Is Associated With Serious Bacterial Infection in Previously Healthy Children Aged 3 to 36 Months With Fever and Extreme Leukocytosis

OBJECTIVES

The aim of the study was to investigate the diagnostic efficacy of C-reactive protein (CRP) in predicting serious bacterial infection (SBI) in febrile children aged 3 to 36 months with extreme leukocytosis (EL), defined as a peripheral white blood cell count of 25,000 to 49,999/mm.

METHODS

The presence of SBI was reviewed in previously healthy children aged 3 to 36 months with a fever of 39°C or higher and EL, who visited a tertiary care hospital emergency department between September 2010 and August 2015. We measured cutoff values of CRP with corresponding likelihood ratios (LRs) and posttest probabilities (PPs).

RESULTS

Of 9989 febrile children, 4252 (42.6%) underwent assays for white blood cell and CRP. Of 233 (5.5%) children with EL, 133 (3.1%) were enrolled, of whom 43 (32.3%; 95% confidence interval [CI], 25.0%-40.7%) had SBI, including 33 pyelonephritis, 5 deep abscesses, 3 lobar pneumonia, and 2 soft tissue infections. With the cutoff of 7.8 mg/dL, the sensitivity of CRP in predicting SBI was 81.4% (95% CI, 67.4%-90.3%); the specificity, 80.0% (95% CI, 70.6%-87.0%); the positive predictive value, 66.0% (95% CI, 52.6%-77.3%); the negative predictive value, 90.0% (95% CI, 81.5%-94.9%); the positive LR, 4.1; and the PP, 66.0% (95% CI, 55.6%-75.0%). A CRP concentration of 16.1 mg/dL or higher yielded an LR of 11.2 and a PP of 84.2% (95% CI, 62.1%-94.5%). A CRP concentration of lower than 3.4 mg/dL yielded an LR of 0.05 and a PP of 2.4% (95% CI, 0.3%-14.6%).

CONCLUSIONS

High concentration of CRP is strongly associated with the presence of SBI in febrile children with EL.

Pneumococcal meningitis before the introduction of 10-valent pneumococcal conjugate vaccine into the National Childhood Immunization Program in Poland

BACKGROUND

Poland introduced the 10-valent conjugate pneumococcal vaccine (PCV10) into the childhood immunization program in January 2017. During previous decades, considerable changes had occurred in the surveillance system for invasive pneumococcal disease. Therefore, to provide baseline data on pneumococcal diseases before PCV10 introduction, we evaluated the epidemiology of pneumococcal meningitis (PM), the only syndrome monitored consistently since 1970.

METHODS

Based on laboratory-confirmed cases reported during 2005-2015, we calculated the reported rates, serotypes distribution and antimicrobial resistance of pneumococcal meningitis isolates. Data from the mandatory national surveillance system was linked with data on cerebrospinal fluid isolates submitted to the National Reference Centre for Bacterial Meningitis. We used negative binomial regression with Newey West method to test for trend in rates of pneumococcal meningitis notified during 2005-2015 and Chi-squared test to assess changes in the serotype distribution from 2008-2011 to 2012-2015.

RESULTS

From 2005 to 2015, the overall reported incidence of PM increased from 0.21 to 0.47 cases per 100,000 population, average yearly increase of 7% (rate ratio 1.07; 95% CI 1.06-1.08). The increase was primarily due to annual increase of 3% (1.02-1.05) among 15-49 years of age, 12% (95% CI: 1.10-1.13) among 50-64 years of age, 18% (95% CI: 1.16-1.19) among persons 65-74 years of age and 9% (95% CI 1.07-1.10) among persons ≥75 years of age. In children <5 years of age, serotypes included in PCV10 and PCV13 accounted for 75% and 80% of reported isolates, respectively. From 2008-2011 to 2012-2015, the proportion of PM cases caused by PCV10 serotypes decreased from 52% to 41% (p < 0.01). Overall, 28% of isolates were resistant to penicillin and 13% were non-susceptible to cefotaxime.

CONCLUSIONS

The introduction of PCV10 into national immunization program may have considerable impact on disease burden, especially on number of cases caused by isolates non-susceptible to antimicrobials.

An assessment of PCV13 vaccine coverage using a repeated cross-sectional household survey in Malawi

Background: The 13-valent pneumococcal conjugate vaccine (PCV13) was introduced in Malawi from November 2011 using a three dose primary series at 6, 10, and 14 weeks of age to reduce Streptococcus pneumoniae-related diseases. To date, PCV13 paediatric coverage in Malawi has not been rigorously assessed.  We used household surveys to longitudinally track paediatric PCV13 coverage in rural Malawi. Methods: Samples of 60 randomly selected children (30 infants aged 6 weeks to 4 months and 30 aged 4-16 months) were sought in each of 20 village clinic catchment 'basins' of Kabudula health area, Lilongwe, Malawi between March 2012 and June 2014. Child health information was reviewed and mothers interviewed to determine each child's PCV13 dose status and vaccine timing. The survey was completed six times in 4-8 month intervals. Survey inference was used to assess PCV13 dose coverage in each basin for each age group. All 20 basins were pooled to assess area-wide vaccination coverage over time, by age in months, and adherence to the vaccination schedule. Results: We surveyed a total of 8,562 children in six surveys; 82% were in the older age group. Overall, in age-eligible children, two-dose and three-dose coverage increased from 30% to 85% and 10% to 86%, respectively, between March 2012 and June 2014.  PCV13 coverage was higher in the older age group in all surveys. Although it varied by basin, PCV13 coverage was consistently delayed: median ages at first, second and third doses were 9, 15 and 21 weeks, respectively. Conclusion: In our rural study area, PCV13 introduction did not meet the Malawi Ministry of Health one-year three-dose 90% coverage target, but after 2 years reached levels likely to reduce the prevalence of both invasive and non-invasive paediatric pneumococcal diseases. Better adherence to the PCV13 schedule may reduce pneumococcal disease in younger Malawian children.

Incidence of paediatric pneumococcal meningitis and emergence of new serotypes: a time-series analysis of a 16-year French national survey

BACKGROUND

Successive implementation of seven-valent then 13-valent pneumococcal conjugate vaccines (PCVs) led to a marked decrease in pneumococcal disease burden, including pneumococcal meningitis. We assessed the long-term effect of implementation of PCVs on incidence of pneumococcal meningitis in children in France over a 16-year period.

METHODS

We did a quasi-experimental, population-based interrupted time-series analysis with a nationwide prospective survey over 16 years in France, recruiting children aged younger than 15 years from 227 paediatric wards from January, 2001, to December, 2016. The main outcome by the time-series model was the estimated incidence of pneumococcal meningitis per 100 000 children (of a population of 12·6 million children in 2017) before and after PCV7 and PCV13 implementation. The time-series model was based on segmented regression with autoregressive error.

FINDINGS

We enrolled 1778 children with pneumococcal meningitis. PCV13 implementation led to a significant reduction in monthly incidence of pneumococcal meningitis from 0·12 per 100 000 children before PCV13 to a nadir of 0·07 in December, 2014 (-38%, 95% CI -56·1 to -20·4; p<0·0001). A sharp increase occurred during 2015 and 2016, (+2·3% per month, incidence of 0·13 per 100 000 children at the end of the study period, p=0·0002), mainly related to an increase of serotype 24F, which was frequently penicillin resistant.

INTERPRETATION

The early effect of PCV13 implementation greatly reduced the incidence of pneumococcal meningitis in children less than 15 years old. However, a sharp rebound in incidence linked to the emergence of serotype 24F compromised the long-term PCV efficacy. If confirmed in future studies and in other countries, pneumococcal meningitis incidence rebound and 24F emergence should be considered when developing next-generation PCVs.

FUNDING

The French Pediatric Infectious Diseases Group, Association Clinique et Thérapeutique Infantile du Val de Marne, Pfizer, and for the National Reference Centre for Pneumococci, the French National Health Agency.

Childhood Deaths Attributable to Invasive Pneumococcal Disease in England and Wales, 2006-2014

Background

Pneumococcal conjugate vaccines (PCVs) are highly effective in preventing invasive pneumococcal disease (IPD), but deaths due to IPD still occur. We aimed to describe children who died of IPD since PCV introduction in England and Wales.

Methods

Public Health England conducts enhanced IPD surveillance in England and Wales. IPD cases in PCV-eligible children aged <5 years (born since 4 September 2004 and diagnosed between 4 September 2006 and 3 September 2014) were actively followed up by postal questionnaires and, for fatal cases, detailed information was requested prospectively from multiple sources.

Results

During the 8-year period, there were 3146 IPD cases and 150 IPD-related deaths (case fatality rate, 4.8%). Overall, 132 isolates from fatal cases were serotyped (88%) and 35 distinct serotypes were identified, with no serotype predominance. Most deaths occurred in children aged <1 year (88/150 [59%]) and 1-year-olds (36/150 [24%]). One-third (53/150 [35%]) had a known risk factor for IPD. Clinical presentation varied with age but not by serotypes in the different conjugate vaccines. Meningitis was diagnosed in nearly half the fatal cases (71/150 [47%]). The IPD-related mortality rate declined after 7-valent PCV introduction from 1.25/100000 children in 2006-2007 to 0.60/100000 in 2009-2010, with a further reduction following 13-valent PCV introduction from April 2010 to 0.39/100000 in 2013-2014 (14 deaths; incidence rate ratio, 0.31 [95% confidence interval, .16-.61]; P = .0003), when most deaths were due to nonvaccine serotypes or in neonates.

Conclusions

Most fatal IPD cases are currently not vaccine-preventable. Additional strategies will be required to reduce childhood pneumococcal deaths in countries with established pneumococcal vaccination programs.

Case-control study shows that neonatal pneumococcal meningitis cannot be distinguished from group B Streptococcus cases

AIM

Streptococcus pneumoniae (S. pneumoniae) is sometimes implicated in neonatal bacterial meningitis. This study described the demographic, clinical and biological features of neonatal S. pneumoniae meningitis and compared pneumococcal and group B streptococcal (GBS) neonatal meningitis.

METHODS

We conducted a case-control study that compared neonates, aged one to 28 days with S. pneumoniae meningitis or GBS meningitis. Each case with S. pneumoniae was randomly matched to four control patients with GBS by age group and study year.

RESULTS

From 2001 to 2013, the national French paediatric network, which comprises 227 paediatric wards, recorded 831 neonatal cases of meningitis. S. pneumoniae (n = 18, 2.2%) was the fifth infection cause after GBS (n = 464, 55.8%), Escherichia coli (n = 232, 27.9%), Neisseria meningitidis (n = 23, 2.8%) and Listeria monocytogenes (n = 20, 2.4%). Neonatal pneumococcal and GBS meningitis did not differ in demographic data or clinical and biological characteristics. All S. pneumoniae strains were fully susceptible to cefotaxime, and we observed a decrease of 13-valent pneumococcal conjugate vaccine (PCV13) serotypes (88.9%-20.0%) after PCV13 implementation.

CONCLUSION

Clinically and biologically, neonatal pneumococcal meningitis could not be distinguished from GBS cases. A herd effect of PCV13 implementation was suggested by the decrease in the prevalence of vaccine serotypes.

Impact of pneumococcal conjugate vaccine (PCV7 and PCV13) on pneumococcal invasive diseases in Italian children and insight into evolution of pneumococcal population structure

BACKGROUND

The use of PCV7 for children immunization was gradually implemented in the Italian regions starting from 2006 and was replaced by PCV13 in 2010-2011. In this study we aimed to assess the PCV impact on invasive pneumococcal diseases (IPD) incidence, serotype distribution and antibiotic resistance in Italian children under 5years old.

METHODS

All IPD cases in children from 5 Italian regions (Emilia-Romagna, Lombardia, A. P. Bolzano, A. P. Trento, and Piemonte) reported through the nationwide surveillance system during 2008-2014 were included in this study. Pneumococcal isolates were subjected to serotyping, antibiotic susceptibility testing, and clonal analysis according to standard methods.

RESULTS

During the study period overall IPD incidence decreased from 7.8 cases/100,000 inhabitants in 2008 to 3.0 cases/100,000 in 2014 (61% decrease, P<0.001). In particular, from 2008 to 2014, PCV7-type IPD decreased from 2.92 to 0.13 cases/100,000 inhabitants (95% decrease, P<0.001) while PCV13-non-PCV7 type IPD decreased from 3.2 to 0.89 cases/100,000 inhabitants (72% decrease, P=0.008). Conversely, non-vaccine serotype (NVS) IPD increased overtime, becoming more common than PCV13 serotype IPD in 2013-2014. Emergent NVS 24F and 12F were the most prevalent in 2014. Antibiotic resistance testing revealed an overall increasing trend in penicillin resistance, from 14% in 2008 to 23% in 2014. Erythromycin resistance showed a downward trend, from 38% in 2008 to 27% in 2014. While in 2008 PCV13 serotypes were the major responsible for antibiotic resistance, during the following years antimicrobial resistance due to NVS increased, mainly as a result of expansion of pre-existing clones.

CONCLUSIONS

Both PCVs led to a substantial decrease in vaccine-related IPD incidence in the children population. However NVS-related IPD increased, becoming the most prevalent in the last two-years period. Continuous surveillance is an essential tool to monitor evolution of pneumococcal population causing IPD in children.

Serotype distribution of Streptococcus pneumoniae causing invasive disease in children in the post-PCV era: A systematic review and meta-analysis

BACKGROUND

Routine immunisation with pneumococcal conjugate vaccines (PCV7/10/13) has reduced invasive pneumococcal disease (IPD) due to vaccine serotypes significantly. However, an increase in disease due to non-vaccine types, or serotype replacement, has been observed. Serotypes' individual contributions to IPD play a critical role in determining the overall effects of PCVs. This study examines the distribution of pneumococcal serotypes in children to identify leading serotypes associated with IPD post-PCV introduction.

METHODS

A systematic search was performed to identify studies and surveillance reports (published between 2000 and December 2015) of pneumococcal serotypes causing childhood IPD post-PCV introduction. Serotype data were differentiated based on the PCV administered during the study period: PCV7 or higher valent PCVs (PCV10 or PCV13). Meta-analysis was conducted to estimate the proportional contributions of the most frequent serotypes in childhood IPD in each period.

RESULTS

We identified 68 studies reporting serotype data among IPD cases in children. We analysed data from 38 studies (14 countries) where PCV7 was administered and 20 (24 countries) where PCV10 or PCV13 have been introduced. Studies reported early and late periods of PCV7 administration (range: 2001∓13). In these settings, serotype 19A was the most predominant cause of childhood IPD, accounting for 21.8% (95%CI 18.6∓25.6) of cases. In countries that have introduced higher valent PCVs, study periods were largely representative of the transition and early years of PCV10 or PCV13. In these studies, the overall serotype-specific contribution of 19A was lower (14.2% 95%CI 11.1∓18.3). Overall, non-PCV13 serotypes contributed to 42.2% (95%CI 36.1∓49.5%) of childhood IPD cases. However, regional differences were noted (57.8% in North America, 71.9% in Europe, 45.9% in Western Pacific, 28.5% in Latin America, 42.7% in one African country, and 9.2% in one Eastern Mediterranean country). Predominant non-PCV13 serotypes overall were 22F, 12F, 33F, 24F, 15C, 15B, 23B, 10A, and 38 (descending order), but their rank order varied by region.

CONCLUSION

Childhood IPD is associated with a wide number of serotypes. In the early years after introduction of higher valent PCVs, non-PCV13 types caused a considerable proportion of childhood IPD. Serotype data, particularly from resource-limited countries with high burden of IPD, are needed to assess the importance of serotypes in different settings. The geographic diversity of pneumococcal serotypes highlights the importance of continued surveillance to guide vaccine design and recommendations.

Risk Factors in Children Older Than 5 Years With Pneumococcal Meningitis: Data From a National Network

BACKGROUND

The occurrence of meningitis in children >5 years old may be associated with specific predisposing factors that can be anatomic, such as cerebrospinal fluid fistula or breach, or related to genetic susceptibility or N inborn or acquired immunologic defect. This study aimed to assess the anatomical and immunologic risk factors in children >5 years old with pneumococcal meningitis and prospectively enrolled in the French national meningitis network.

METHODS

We analyzed all data for children who were 5-15 years old with a diagnosis of pneumococcal meningitis between 2001 and 2013. We describe the frequency and typology of the anatomic or immunologic risk factors, the clinical features and the pneumococcal serotypes.

RESULTS

Among the 316 patients with pneumococcal meningitis, the mortality rate was 9.5% and 23.1% of cases presented complications (abscess, coma, hemodynamic failure, thrombophlebitis cerebral or deafness). In total, 108 children (34%) showed risk factors, the most frequent being anatomic: 70 cases (22.8%) were related to a cerebrospinal fluid breach or fistula and 55 (17.9%) to immunodeficiency, primary or acquired. Serotype data were available for 207 pneumococcal isolates (65.5%). The most frequent serotypes were as follows: 3, 18C, 19A and 19F between 2001 and 2009 and 19F, 3, 19A, 12F, 22F, 17F and 24F after 2009.

CONCLUSIONS

We describe the largest cohort of children >5 years old with pneumococcal meningitis. One third of the children had risk factors justifying a complete immunologic and radiologic work-up.

Risk factors for community-acquired bacterial meningitis

BACKGROUND

Bacterial meningitis is a significant burden of disease and mortality in all age groups worldwide despite the development of effective conjugated vaccines. The pathogenesis of bacterial meningitis is based on complex and incompletely understood host-pathogen interactions. Some of these are pathogen-specific, while some are shared between different bacteria.

METHODS

We searched the database PubMed to identify host risk factors for bacterial meningitis caused by the pathogens Streptococcus pneumoniae, Neisseria meningitidis and Haemophilus influenzae type b, because they are three most common causative bacteria beyond the neonatal period.

RESULTS

We describe a number of risk factors; including socioeconomic factors, age, genetic variation of the host and underlying medical conditions associated with increased susceptibility to invasive bacterial infections in both children and adults.

CONCLUSIONS

As conjugated vaccines are available for these infections, it is of utmost importance to identify high risk patients to be able to prevent invasive disease.

Of the Phrensy: an update on the epidemiology and pathogenesis of bacterial meningitis in the pediatric population

In the past century, advances in antibiotics and vaccination have dramatically altered the incidence and clinical outcomes of bacterial meningitis. We review the shifting epidemiology of meningitis in children, including after the implementation of vaccines that target common meningitic pathogens and the introduction of intrapartum antibiotic prophylaxis offered to mothers colonized with Streptococcus agalactiae. We also discuss what is currently known about the pathogenesis of meningitis. Recent studies of the human microbiome have illustrated dynamic relationships of bacterial and viral populations with the host, which may potentiate the risk of bacterial meningitis.

Impact of pneumococcal conjugate vaccines on pneumococcal meningitis cases in France between 2001 and 2014: a time series analysis

BACKGROUND

Pneumococcal meningitis (PM) is a major invasive pneumococcal disease. Two pneumococcal conjugate vaccines (PCVs) have been introduced in France: PCV7 was recommended in 2003 and replaced in 2010 by PCV13, which has six additional serotypes. The impact of introducing those vaccines on the evolution of PM case numbers and serotype distributions in France from 2001 to 2014 is assessed herein.

METHODS

Data on 5166 Streptococcus pneumoniae strains isolated from cerebrospinal fluid between 2001 and 2014 in the 22 regions of France were obtained from the National Reference Center for Pneumococci. The effects of the different vaccination campaigns were estimated using time series analyses through autoregressive moving-average models with exogenous variables ("flu-like" syndromes incidence) and intervention functions. Intervention functions used 11 dummy variables representing each post vaccine epidemiological period. The evolution of serotype distributions was assessed for the entire population and the two most exposed age groups (<5 and > 64 years old).

RESULTS

For the first time since PCV7 introduction in 2003, total PM cases decreased significantly after starting PCV13 use: -7.1 (95% CI, -10.85 to -3.35) cases per month during 2013-2014, and was confirmed in children < 5 years old (-3.5; 95% CI, -4.81 to -2.13) and adults > 64 years old (-2.0; 95% CI, -3.36 to -0.57). During 2012-2014, different non-vaccine serotypes emerged: 12F, 24F in the entire population and children, 6C in the elderly; serotypes 3 and 19F persisted in the entire population.

CONCLUSIONS

Unlike other European countries, the total PM cases in France declined only after introduction of PCV13. This suggests that vaccine pressure alone does not explain pneumococcal epidemiological changes and that other factors could play a role. Serotype distribution had changed substantially compared to the pre-vaccine era, as in other European countries, but very differently from the US. A highly reactive surveillance system is thus necessary not only to monitor evolutions due to vaccine pressure and to verify the local serotypic appropriateness of new higher-valent pneumococcal vaccines, but also to recognise and prevent unexpected changes due to other internal or external factors.

The multifaceted impact of pneumococcal conjugate vaccine implementation in children in France between 2001 to 2014

In 2003, France was the first European country to recommend 7-valent pneumococcal conjugate vaccine (PCV7) for a large proportion of healthy children. With complicated recommendations, the vaccine coverage during the first 4 y of implementation was low, then progressively increased to reach 90% in 2008. The aim of this review was to describe the particular impact of PCVs in a country where the vaccine coverage was initially suboptimal. After PCV7 implementation, the PCV7 serotypes nearly disappeared among pneumococci isolated from meningitis (-73%), other invasive pneumococcal disease (IPD; -90%) and pneumococcal carriage (-97%). Consequently, the rates of penicillin-resistant strains declined. However, because of important serotype replacement, the global effect on the incidence of meningitis (-31%) or other IPD (-14%) was modest and observed only in young children < 2 y old. After PCV13 transition, with immediate high vaccine coverage, the vaccine had an important impact on all pneumococcal disease: reduction of -20% for pneumococcal meningitis, -36% for non-meningitis IPD, -32% for community acquired pneumonia and -15% for S. pneumoniae carriage. These findings underline the complexity of pneumococcal epidemiology and the importance of high and fast vaccination coverage to obtain the optimal effect of PCVs.

Complications of Pneumococcal Bacteremia After Thirteen-valent Conjugate Vaccine Withdrawal

BACKGROUND

In the Region of Madrid, universal immunization with the 13-serotypes pneumococcal conjugate vaccine (PCV13) started in May 2010. In July 2012, public funding ceased. Vaccination coverage decreased from >95% to 82% in 2013 and to 67% in 2014. Our aim was to investigate the impact of PCV13 withdrawal from Madrid Region universal immunization program on the incidence of complicated pneumococcal bacteremia.

METHODS

We performed a multicenter retrospective cohort study, from 2009 to 2014. Participants were children aged <14 years with Streptococcus pneumoniae bacteremia. Complications were defined as any condition requiring intensive care or surgery. Sequelae were conditions lasting ≥90 days.

RESULTS

A total of 168 patients were recruited. One-fourth of both immunized and nonimmunized patients had complications. Global complications increased after PCV13 withdrawal. About 28% of PCV13 serotypes presented complications. Complications caused by PCV13 serotypes did not increase after July 2012. Non-PCV13 serotypes increased progressively from 2009 on, and 23% presented complications. A significant risk of complications was found for patients with meningitis, empyema, C-reactive protein >100 mg/L and serotype 1. A multivariate analysis indicated that complications were associated with meningitis and hospital admission after July 2012. Sequelae were significantly associated with children <2 years of age, meningitis and non-PCV13 serotypes.

CONCLUSIONS

The incidence of complications caused by PCV13 serotypes did not increase 2 years after PCV13 withdrawal. Nevertheless, all-serotypes complications increased. The likely cause was that non-PCV13 serotypes (associated with meningitis) are on the rise.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Epidemiology of Invasive Pneumococcal Disease in Czech Children under 5 Years of Age after Routine Immunisation

BACKGROUND

The introduction of the surveillance of invasive pneumococcal diseases (IPD) in 2007 has helped to monitor changes in serotype occurrence in the Czech population and assess the impact of routine immunisation against IPD on the child population under 5 years of age.

METHODS

Observational study of childhood IPD in the Czech Republic based on the state public health surveillance data comparing pre-immunisation (2007-2008) and post-immunisation (2012-2013) periods.

RESULTS

In the child population there was an overall decline in IPD occurrence of 46.6% (95% CI 63.4-21.9) observed during the post-immunisation period. There was even greater decrease of 71.6% (95% CI 50.4-83.8) in vaccinated children. In the post-immunisation period, Prevenar 13 (PCV13) and Synflorix (PCV10) contributed to a vaccine-type IPD reduction of 95.4% (95% CI 67.0-99.4) and 76.9% (95% CI 36.0-91.7), respectively, compared to unimmunised children. The occurrence of 10 serotypes contained in both commercial vaccines also decreased in unvaccinated children by 61.4% (95% CI 14.5-82.6). However, a rise in the risk of non-vaccine and unspecified serotype acquisition by up to 153% was revealed in unimmunised children when comparing post-immunisation and pre-immunisation periods.

CONCLUSIONS

The findings suggest a shift in IPD caused either by vaccine or non-vaccine serotypes between immunised and unimmunised populations of children, which could result in increased incidence of IPD caused by non-vaccine serotypes. Therefore, routine immunisation using only one vaccine with broader serotype coverage together with a higher vaccination rate could raise hopes of further decrease in IPD in the child population.

Population structure of invasive Streptococcus pneumoniae isolates among Alaskan children in the conjugate vaccine era, 2001 to 2013

Here we describe the relationships between serotypes, genotypes, and antimicrobial susceptibility among isolates causing invasive pneumococcal disease in Alaskan children during the pneumococcal conjugate vaccine (PCV) era. From 2001 to 2013 we received 271 isolates representing 33 serotypes. The most common serotypes were 19A (29.5%, n= 80), 7F (12.5%, n= 34), 15B/C (6.3%, n= 17), and 22F (4.8%, n= 13). Multilocus sequence typing identified 11 clonal complexes (CC) and 45 singletons. Five CCs accounted for 52% (141/271) of the total: CC199 (21% [n= 57], serotypes 19A, 15B/C), CC191 (12.2% [n= 33], serotype 7F), CC172 (10.3% [n= 28], serotypes 19A, 23A, 23B), CC433 (4.4% [n= 12], serotype 22F), and CC100 (4.4% [n= 12], serotype 33F). The proportion of isolates nonsusceptible to erythromycin and tetracycline increased after 13-valent PCV use (14% [n= 30] versus 29% [n= 14]; P= 0.010) and (4% [n= 9] versus 22% [n= 11]; P< 0.001), respectively. The genetic diversity also increased after 13-valent PCV use (Simpson's diversity index =0.95 versus 0.91; P= 0.022).

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

Vaccines reduced invasive infections due to PCV7 serotypes.

Insight Into Resistance Phenotypes of Emergent Non 13-valent Pneumococcal Conjugate Vaccine Type Pneumococci Isolated From Invasive Disease After 13-valent Pneumococcal Conjugate Vaccine Implementation in France

Background.  In 2010, the pneumococcal 13-valent conjugate vaccine (PCV13), containing 6 additional serotypes including the multidrug-resistant 19A, replaced the PCV7 in France. This study aimed at analyzing trends in antibiotic resistance in invasive pneumococcal disease (IPD) isolates in France after PCV13 introduction. Methods.  A total of 5243 pneumococci isolated from IPD in 2008-2009 (late PCV7 era) and 2011-2012 (PCV13 era) were studied according to their serotype and antibiotic resistance profile. Multilocus sequence typing analysis was performed on strains of the predominant serotypes (12F and 24F) isolated from young children. Results.  Overall, the prevalence of antibiotic resistance decreased in France (-21.5% for penicillin from 2008-2009 to 2011-2012), mainly driven by the decline of the 19A serotype. Among non-PCV13 serotypes that concomitantly emerged, serotypes 12F, 24F, 15A, and 35B were consistently associated with resistance to 1 or more antibiotics. In children under 2 years, serotypes 15A, 35B, and 24F accounted together for 37.8% and 31.9% of penicillin-nonsusceptible and erythromycin-resistant isolates, respectively. Chloramphenicol and cotrimoxazole resistance were mainly associated with serotypes 12F and 24F, respectively. Genetic analysis showed that although emergence of serotype 12F pneumococci resulted from the expansion of various pre-existing lineages, increase in serotype 24F was related to the clonal expansion of the ST162 penicillin-susceptible cotrimoxazole-resistant lineage. Conclusions.  We showed that decline of PCV13-related IPD was associated with a decline in antibiotic resistance in France, but that it likely favored the spread of several resistant nonvaccine serotypes. However, antibiotic resistance does not seem to be the only element that may drive this phenomenon.

Racial and Regional Differences in Rates of Invasive Pneumococcal Disease

BACKGROUND AND OBJECTIVES

Invasive pneumococcal disease (IPD) remains an important cause of illness in US children. We assessed the impact of introduction of the 13-valent pneumococcal conjugate vaccine (PCV13) on pediatric IPD rates, as well as changes in racial and regional differences in IPD, in Tennessee.

METHODS

Data from active laboratory and population-based surveillance of IPD were used to compare IPD rates in the early-PCV7 (2001-2004), late-PCV7 (2005-2009), and post-PCV13 (2011-2012) eras. IPD rates were further stratified according to age, race, and region (east and middle-west TN).

RESULTS

Among children aged <2 years, IPD rates declined by 70% from 67 to 19 per 100 000 person-years in the early-PCV7 era and post-PCV13 era, respectively. Similar decreasing trends in IPD rates were observed in older children aged 2 to 4 years and 5 to 17 years. In the late-PCV7 era, IPD rates in children aged <2 years were higher in black children compared with white children (70 vs 43 per 100 000 person-years); however, these racial differences in IPD rates were no longer significant after PCV13 introduction. Before PCV13, IPD rates in children aged <2 years were also higher in east Tennessee compared with middle-west Tennessee (91 vs 45 per 100 000 person-years), but these differences were no longer significant in the post-PCV13 era.

CONCLUSIONS

PCV13 introduction led to substantial declines in childhood IPD rates and was associated with reduced regional and racial differences in IPD rates in Tennessee.

Invasive disease potential of pneumococci before and after the 13-valent pneumococcal conjugate vaccine implementation in children

BACKGROUND

Changes in serotype distribution have been induced after pneumococcal conjugate vaccines (PCV) implementation, and non-vaccine serotypes are now circulating. Among these latter serotypes, we aimed to distinguish those with high invasive disease potential before (2008-2009) and after PCV13 implementation (2012-2013).

METHODS

Invasive pneumococcal disease (IPD) serotypes isolated from children 6 to 24 months were compared with nasopharyngeal-colonizing serotypes in healthy children. To assess the invasive potential of a given serotype, odds ratios (ORs) were calculated. For each serotype, OR >1 indicated increased probability of association with IPD and OR <1 decreased probability.

RESULTS

In 2008/2009 and 2012/2013, 355 pneumococci were isolated from 1212 healthy children and from 569 IPD, including 166 meningitis, 114 pneumonia, and 289 other IPDs. In period 1, serotypes 7F, 3, 1, 24F, and 19A showed highly significant invasive disease potential whereas in period 2, only serotype 24F was associated with a significant high OR (6.6 [95% CI 2.6; 16.2]). Of note, for serotype 12F, OR could not be calculated because of no carrier recorded, however, if there had been a single 12F carrier, the OR would be among the highest, in period 2, 15.7 [95% 3.4; 73.0]). Only two serotypes appeared negatively associated with IPD, 11A and 23B in the period 2 as compared with nine in period 1. In the second period, pneumococcal penicillin non-susceptible isolates were mostly represented by serotypes 19A, 15A, 19F, 35B and 24F both in carriers and IPD. Only one strain was resistant to penicillin with MIC=4 μg/ml (serotype 19A) during the first period.

CONCLUSION

In children <2 years old, compared to the previous period, the number of serotypes having a high disease potential decreased after PCV13 implementation, only two non-vaccine serotypes, 24F and 12F, had high invasive disease potential.

Pneumococcal Meningitis Vaccine Breakthroughs and Failures After Routine 7-Valent and 13-Valent Pneumococcal Conjugate Vaccination in Children in France

We collected cases of pneumococcal meningitis vaccine breakthrough (VBT) and vaccine failure (VF) from 2003 to 2013 after the implementation of pneumococcal conjugate vaccines (PCVs) in France. VBT accounted for 3.2% of the cases (PCV7 era: 24 of 943, PCV13 era: 15 of 290) and VF 0.6% (PCV7 era: 6 of 943, PCV13 era: 2 of 290). VBT and VF are rare and occur in most cases in children younger than 2 years. The serotype 19F was the most frequent cause even after the introduction of PCV13.

Impacts of the 13-Valent Pneumococcal Conjugate Vaccine in Children

Applications of the heptavalent pneumococcal conjugate vaccine (PCV7) in the pediatric immunization schedule have dramatically reduced the incidence of pneumococcal diseases in both vaccinated children and unvaccinated individuals of all ages. However, increased infections caused by non-PCV7 serotypes have been reported by several groups. To overcome this problem, new vaccines covering more serotypes including the emerging serotypes have been developed. The 13-valent pneumococcal conjugate vaccine (PCV13) currently covers the 7 PCV7 serotypes (4, 6B, 9V, 14, 18C, 19F, and 23F) and 6 additional serotypes 1, 3, 5, 6A, 7F, and 19A. After the first year of PCV13 applications in the immunization schedule in young children, global evaluation studies demonstrated that PCV13 provided a wider coverage and more effective prevention than PCV7 against invasive pneumococcal diseases (IPDs), mucosal pneumococcal diseases, and pneumococcal carriage. We reviewed the effects of PCV13 in the control of pneumococcal diseases in children based on previous studies.

Impact of the 13-valent pneumococcal conjugate vaccine on the incidence of pneumococcal meningitis in children

The impact of the 13-valent pneumococcal conjugate vaccine (PCV13) on the incidence of pneumococcal meningitis (PM) in children is unknown. To determine this impact, a descriptive multicentre retrospective cohort study was conducted from 2008 to 2013 in northern France. All laboratory-confirmed PM in children aged <18 years in all hospitals of the area with paediatric units were included. Two independent databases were used for exhaustive identification of cases: medical plus laboratory records at each hospital and discharge codes. The corrected incidence of PM was determined by a capture-recapture analysis using these two databases. Sixty-two cases were found over the 6-year period. A decrease of the PM corrected incidence was observed in the global population (P = 0·07), significant only for children aged <2 years, from 11·9/100 000 in 2008 in 1·9/100 000 in 2013 [6·4 fold-decrease, 95% confidence interval (CI) 1·4-41, P = 0·01] between years 2008 and 2013. When comparing the pre- and post-PCV13 periods, this decrease was still statistically significant for children aged <2 years [7·32/100 000 (95% CI 4·39-10·25) to 2·78/100 000 (95% CI 0·96-4·60), P = 0·01]. Only three (5%) cases of PM caused by vaccine serotypes could have been prevented. After the introduction of the PCV13 vaccine, a decrease in the incidence of PM cases in children in northern France was observed.

Effects of Infant Pneumococcal Conjugate Vaccination on Serotype Distribution in Invasive Pneumococcal Disease among Children and Adults in Germany

This study describes the effects of the introduction of universal infant pneumococcal conjugate vaccination in 2006 on invasive pneumococcal disease (IPD) among children and adults in Germany with a focus on the dynamics of serotype distribution in vaccinated and non-vaccinated age groups. Over a period of 22 years (1992-2014), microbiological diagnostic laboratories from all over Germany have been sending isolates of IPD cases to the German National Reference Center for Streptococci on a voluntary basis. Streptococcus pneumoniae isolates were serotyped using Neufeld's Quellung method. Among children <16 years, the proportion of PCV7 serotypes among isolates from IPD cases decreased from 61.8% before vaccination (1997-2006) to 23.5% in the early vaccination period (2007-2010; p = 1.30E-72) and sank further to 5.2% in the late vaccination period (2010-2014; p = 4.59E-25). Similar reductions were seen for the separate age groups <2 years, 2-4 years and 5-15 years. Among adults, the proportion of PCV7 serotypes decreased from 43.4% in the pre-vaccination period (1992-2006) to 24.7% (p = 3.78E-88) in the early vaccination period and 8.2% (p = 5.97E-161) in the late vaccination period. Both among children and among adults, the non-PCV7 serotypes 1, 3, 7F and 19A significantly increased in the early vaccination period. After the switch from PCV7 to PVC10/PCV13 for infant vaccination in 2010, serotypes 1, 6A and 7F significantly decreased. A decrease in serotype 19A was only observed in 2013-2014, as compared to 2010-2011 (children p = 4.16E-04, adults p = 6.98E-06). Among adults, serotype 3, which strongly increased in the early vaccination period (p = 4.44E-15), remained at a constant proportion in the late vaccination period. The proportion of non-PCV13 vaccine serotypes increased over the whole vaccination period, with serotypes 10A, 12F, 23B, 24F and 38 most significantly increasing among children and serotypes 6C, 12F, 15A, 22F and 23B increasing among adults. Eight years of childhood pneumococcal conjugate vaccination have had a strong effect on the pneumococcal population in Germany, both among the target group for vaccination as well as among older children and adults.

Trends in antibiotic resistance of Streptococcus pneumoniae and Haemophilus influenzae isolated from nasopharyngeal flora in children with acute otitis media in France before and after 13 valent pneumococcal conjugate vaccine introduction

BACKGROUND

After the implementation of pneumococcal conjugate vaccines (PCVs), the marked shift in Streptococcus pneumoniae (Pnc) serotype distribution led to a modification in pneumococcal antibiotic susceptibility. In 2011, the pattern of antibiotic prescription in France for acute otitis media in infants was greatly modified, with decreased use of third-generation cephalosporins and amoxicillin-clavulanate replaced by amoxicillin alone. To assess antibiotic strategies, here we measured the antibiotic susceptibility of Pnc and Haemophilus influenzae (Hi) isolated from nasopharyngeal flora in infants with acute otitis media in the 13-valent PCV (PCV13) era in France.

METHODS

From November 2006 to June 2013, 77 pediatricians obtained nasopharyngeal swabs from infants (6 to 24 months old) with acute otitis media. The swabs were sent for analysis to the national reference centre for pneumococci in France. Demographics, medical history, and physical examination findings were recorded.

RESULTS

We examined data for 7200 children, 3498 in the pre-PCV13 period (2006-2009) and 3702 in the post-PCV13 period (2010-2013). The Pnc carriage rate decreased from 57.9% to 54.2% between the 2 periods, and the proportion of pneumococcal strains with reduced susceptibility to penicillin or resistant to penicillin decreased from 47.1% to 39% (P < 0.0001). The Hi carriage rate increased from 48.2% to 52.4%, with the proportion of ß-lactamase-producing strains decreasing from 17.1% to 11.9% and the proportion of ß-lactamase-nonproducing, ampicillin-resistant strains remaining stable, from 7.7% to 8.2%. We did not identify any risk factor associated with carriage of ß-lactamase-producing Hi strains (such as daycare center attendance, otitis-prone condition or recent antibiotic use).

CONCLUSION

In France, the nasopharyngeal carriage rate of reduced-susceptibility pneumococcal strains and ß-lactamase-producing Hi strains decreased in children with acute otitis media after 2010, the year the PCV13 was introduced. Accordingly, amoxicillin as the first-line drug for acute otitis media requiring antibiotics remains a valid choice.

Impact of the 13-Valent Pneumococcal Conjugate Vaccine on Pneumococcal Meningitis in US Children

BACKGROUND

The impact of 13-valent pneumococcal conjugate vaccine (PCV13) on pneumococcal meningitis (PM) in US children is unknown. We compared the serotype distribution, antibiotic susceptibility, hospital course, and outcomes of children with PM 3 years before and 3 years after the introduction of PCV13.

METHODS

We identified patients ≤ 18 years of age with PM at 8 children's hospitals in the United States. Pneumococcal isolates were collected prospectively. Serotyping and antibiotic susceptibility were performed in a central laboratory. Clinical data were abstracted from medical records. Patients were divided into 3 subgroups: pre-PCV13 (2007-2009), transitional year (2010), and post-PCV13 (2011-2013). Categorical variables were analyzed by the χ(2) test and continuous variables by the Mann--Whitney U test.

RESULTS

During the study period, 173 of 1207 episodes (14%) of invasive pneumococcal disease were identified as PM; 76 of 645 (12%) were during 2007-2009 and 69 of 394 (18%) during 2011-2013 (50% increase; P = .03). The proportion of PCV13 serotype cases decreased from 54% in 2007-2009 to 27% in 2011-2013 (P = .001). Non-PCV13 serotype cases represented 73% of the isolates in 2011-2013. Isolates with ceftriaxone minimum inhibitory concentration ≥ 1 µg/mL decreased (13% to 3%) from 2007-2009 to 2011-2013 (P = .03). No significant differences were identified for hospital course or outcome, with the exception that a greater proportion of patients had subdural empyema and hemiparesis in 2011-2013.

CONCLUSIONS

After the introduction of PCV13, the number of cases of PM in children remained unchanged compared with 2007-2009, although the proportion of PCV13 serotypes decreased significantly. Serotype 19A continued to be the most common serotype in 2011-2013. Antibiotic resistance decreased significantly. Morbidity and case-fatality rate due to PM remain substantial.

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

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

Increase in the nasopharyngeal carriage of non-vaccine serogroup 15 Streptococcus pneumoniae after introduction of children pneumococcal conjugate vaccination in Hong Kong

This study assessed pneumococcal carriage in the early periods after routine use of 13-valent pneumococcal conjugate vaccine (PCV13) in Hong Kong. Nasopharyngeal swabs were obtained from 1110 children (<5 years) admitted with acute illness during September 2010-August 2013. Pneumococcal carriage rate was 13.5% in unvaccinated children, 14.1% in children who had ≥1 PCV dose and 15.3% in children who had ≥3 PCV doses. Nonv-PCV13 serotypes comprised 56.4% of all isolates. The most common serogroup/types were 15 (15A, 5.1%; 15B, 10.3%; 15C, 9.6%; 15F, 0.6%), 19F (17.9%), 6A (7.1%) and 6C (7.1%). Carriage of serogroup 15 was more common among vaccinated children (4.1% versus 0.6%, P = 0.033). Molecular typing revealed that expansion of several clones (clonal complex, CC63, CC199, CC1262, CC3397) was responsible for the increase in serogroup 15. Almost all CC63 and CC3397 isolates were nonsusceptible to both penicillin and erythromycin. The finding highlights the emergence of serogroup 15 following PCV13 use.