Pneumococcal meningitis in the era of pneumococcal conjugate vaccine implementation

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

BACKGROUND

Streptococcus pneumoniae remains an important cause of bacterial meningitis in children younger than 2 years. Here, we analyzed data from an active surveillance network established 12 years ago by the Pediatric Infectious Disease Group and the Pediatric Clinical and Therapeutical Association to analyze the impact of pneumococcal conjugate vaccine (PCV7 implemented in 2002 and PCV13 in 2010) on pneumococcal meningitis (PM).

METHODS

Two hundred twenty-seven pediatric wards working with 168 microbiology departments throughout France were asked to report all cases of PM.

RESULTS

From 2001 to 2012, among 4808 bacterial meningitis cases, 1406 cases of PM (29.2%) were reported. After PCV13 implementation, from 2009 to 2012, the number of cases significantly decreased by 27.4% (P = 0.041, Cuzick trend test). For children younger than 2 years, the decrease was 28.2% (P = 0.039, Cuzick trend test). In the same period, the decrease was 66.7% in cases due to 6 additional PCV13 types, and the number of cases due to nonvaccine types remained stable. In 2012, the non-PCV13 serotype represented 67.6% of cases and were mainly represented by 12F (15%), 24F (15%), 22F (7%) and 15B/C (7%). For 88.6% of cases, initial antibiotic treatment was vancomycin with a third-generation cephalosporin. Overall mortality was 10.6%, most deaths (86.4%) occurred before day 15.

CONCLUSIONS

Two years after the PCV13 implementation, we found an impact on PM cases particularly for children younger than 2 years.

Trends in asymptomatic nasopharyngeal colonization with streptococcus pneumoniae after introduction of the 13-valent pneumococcal conjugate vaccine in Calgary, Canada

BACKGROUND

We previously reported serotype-specific trends in pneumococcal nasopharyngeal colonization soon after introduction of the 7-valent pneumococcal conjugate vaccine (PCV7) in mid-2002. Our current aim is to describe later trends after PCV7 and early trends after PCV13 vaccine introduction in 2010.

METHODS

The Calgary Area Streptococcus pneumoniae Epidemiology Research team conducted 10 point-prevalence surveys of pneumococcal nasopharyngeal colonization in healthy children aged 12 and 18 months and 4.5 years biannually from 2003 to 2005 (previously reported) and annually in 2006, 2010, 2011 and 2012.

RESULTS

For surveys conducted during 2010-2012, the proportion colonized was 13.2% compared with 19.9% in surveys conducted during 2003-2006 (P < 0.001). Vaccination with 2 or more doses of PCV7 or PCV13, older age and recent antibiotic use reduced the odds of colonization with any pneumococcus. By 2012, 94% of all isolates were nonvaccine serotypes with 11A, 15A/B/C, 22F, 23A/B and 35B/F representing 75% of all isolates.

CONCLUSIONS

Pneumococcal nasopharyngeal colonization has changed profoundly since the introduction of conjugate vaccines and overall colonization by pneumococcus has declined in recent years. By 2012, nonvaccine serotypes have nearly completely replaced vaccine serotypes. The impact on clinical disease remains to be seen.

Optimising assessments of the epidemiological impact in The Netherlands of paediatric immunisation with 13-valent pneumococcal conjugate vaccine using dynamic transmission modelling

This work is the first attempt to quantify the overall effects of a 13-valent pneumococcal conjugate vaccine (PCV13) vaccination programme in the Dutch population taking into account all the direct and indirect effects of the vaccine on invasive pneumococcal disease. Using available Dutch data, a dynamic transmission model for the spread of pneumococci and potential subsequent invasive pneumococcal disease has been adapted to the Dutch setting. Overall, invasive pneumococcal disease cases in the Netherlands are predicted to decrease from a pre-vaccination level of 2623 cases annually to 2475, 2289, 2185, 2179, and 2178 cases annually 5-, 10-, 20-, 30-, and 40-years, respectively, post-vaccination. Therefore, vaccination with PCV13 in the Netherlands is predicted to lower invasive pneumococcal disease cases per year by up to 445 cases in the medium- to long-term. The results are quite robust for the sensitivity analyses performed on the parameters that regulate herd immunity and competition between vaccine and non-vaccine types.

Pneumococcal meningitis in children: epidemiology, serotypes, and outcomes from 1997-2010 in Utah

BACKGROUND

After licensure of the 7-valent pneumococcal conjugate vaccine (PCV7) in the United States in 2000, the incidence of pediatric pneumococcal meningitis decreased significantly. However, cases continue to occur. It is unknown whether meningitis due to PCV7 and non-PCV7 serotypes causes similar morbidity and mortality.

METHODS

We performed a retrospective cohort study of laboratory-confirmed pneumococcal meningitis among Utah children from 1997 to 2010. We reviewed medical records and obtained clinical data during the acute illness and follow-up data on neurologic sequelae.

RESULTS

Sixty-eight cases of meningitis were identified. PCV7 serotypes caused 64% of cases before and 25% of cases after licensure of PCV7 (P < .01). The age range was similar before and after PCV7 licensure (P = .5). The overall case fatality rate was 13% and was similar among cases caused by PCV7 and non-PCV7 serotypes (P = .7). Children with PCV7 serotypes were more likely to require mechanical ventilation (68% vs 34%; P < .01). Of all survivors, 63% had neurologic sequelae, and the proportion was similar after infection with PCV7 or non-PCV7 serotypes (P = .1). More than one-half (54%) of all children who developed pneumococcal meningitis in the PCV7 period were eligible for PCV7 and had not been immunized.

CONCLUSIONS

Pneumococcal meningitis continues to be associated with high mortality and morbidity; death and neurologic sequelae are common with both PCV7 and non-PCV7 serotype meningitis. The substantial burden of this disease and continued cases among unimmunized children reinforce the need for more effective immunization strategies and continued surveillance in the era of PCV13.

Pediatric invasive pneumococcal disease caused by vaccine serotypes following the introduction of conjugate vaccination in Denmark

A seven-valent pneumococcal conjugate vaccine (PCV7) was introduced in the Danish childhood immunization program (2+1 schedule) in October 2007, followed by PCV13 starting from April 2010. The nationwide incidence of IPD among children younger than 5 years nearly halved after the introduction of PCV7 in the program, mainly due to a decline in IPD caused by PCV7-serotypes. We report the results from a nationwide population-based cohort study of laboratory confirmed IPD cases in children younger than 5 years during October 1, 2007 to December 31, 2010 and describe the characteristics of children suspected to present with a vaccine failure. The period between April 19 and December 31, 2010 was considered a PCV7/PCV13 transitional period, where both vaccines were offered. We identified 45 episodes of IPD caused by a PCV7 serotype (23% of the total number) and 105 (55%) caused by one of the 6 additional serotypes in PCV13. Ten children had received at least one PCV7 dose before the onset of IPD caused by a PCV7 serotype. Seven children were considered to be incompletely vaccinated before IPD, but only three cases fulfilled the criteria of vaccine failure (caused by serotypes 14, 19F and 23F). One case of vaccine failure was observed in a severely immunosuppressed child following three PCV7 doses, and two cases were observed in immunocompetent children following two infant doses before they were eligible for their booster. None of the IPD cases caused by the additional PCV13 serotypes had been vaccinated by PCV13 and there were therefore no PCV13-vaccine failures in the first 8-months after PCV13 introduction in Denmark.

Eradication of invasive pneumococcal disease due to the seven-valent pneumococcal conjugate vaccine serotypes in Calgary, Alberta

BACKGROUND

The seven-valent pneumococcal conjugate vaccine (PCV7) was licensed in Canada in 2001. Routine infant vaccination programs in Alberta began in 2002. Several years after PCV7 introduction, the routine use of PCV7 in infants and high-risk children has led to near elimination of invasive pneumococcal disease (IPD) caused by vaccine serotypes.

METHODS

Prospective, population-based surveillance of all IPD cases was conducted from January 1998 to December 2010. Demographic, clinical and microbiologic data were collected.

RESULTS

There were 1462 IPD cases over 13 years. Comparing PCV7 serotype IPD incidence in the prevaccine period (1998-2001) to the late postvaccine period (2007-2010), there were declines in children 0-5 months (100%), 6-23 months (98%), 2-4 years (97%), 5-15 years (100%) as well as in adults 16-64 years (73%), 65-84 years (90%) and ≥85 years of age (100%). From 2008 to 2010, there were no cases of PCV7 serotype IPD in children under 2 years of age. There have been increases in non-PCV7 serotype IPD; notably, serotypes 5 and 19A have increased significantly in adults and 19A in children.

CONCLUSIONS

PCV7 serotype IPD has been eliminated in vaccine-eligible young children and nearly eliminated in all other age groups. Serotype 19A increased significantly at all ages before the introduction of an expanded valency pneumococcal conjugate vaccine.

Pneumococcal vaccines for children: a global public health priority

Pneumococcal conjugated vaccines have been recommended in children for over a decade in many countries worldwide. Here we review the development of pneumococcal vaccines with a focus on the two types currently available for children and their safety record. We discuss also the effect of vaccines, including the 13-valent pneumococcal conjugate vaccine, on invasive pneumococcal diseases in children, particularly bacteraemia, pneumonia and meningitis, as well as on mucosal disease and carriage. In regions where immunization was implemented in young children, the number of invasive pneumococcal diseases decreased significantly, not only in the target age group, but also in younger and much older subjects. Challenges and future perspectives regarding the development of new 'universal' vaccines, which could bypass the current problem of serotype-specific protection in a context of serotype replacement, are also discussed.

Four years of universal pneumococcal conjugate infant vaccination in Germany: impact on incidence of invasive pneumococcal disease and serotype distribution in children

INTRODUCTION

Vaccination with pneumococcal conjugate vaccine (PCV) for all children <2 years was recommended in Germany in July 2006. Initially PCV7 was exclusively used; PCV10 became available from April 2009 and PCV7 was replaced by PCV13 in December 2009.

OBJECTIVE

To compare the incidence and serotype distribution of invasive pneumococcal disease (IPD) for pneumococcal meningitis and non-meningitis IPD in children from 2007 to 2010 with reference to the pre-vaccination period from 1997 to 2001.

METHODS

Nationwide surveillance of IPD for children <16 years in Germany was based on two independent reporting sources: active surveillance in paediatric hospitals and passive web-based surveillance through microbiological laboratories. Serotyping was performed using the Neufeld Quellung reaction.

CASE DEFINITION

isolation of Streptococcus pneumoniae from a normally sterile body site. IPD incidence was estimated by capture-recapture analysis. Rate ratios comparing post- to pre-vaccination incidence were calculated as well as PCV7 and non-PCV7 serotype specific incidences.

RESULTS

While PCV7 incidence decreased by 88% (95%CI: 83 to 91) in children <16 years both in pneumococcal meningitis and non-meningitis IPD, an increase in Non-PCV7 serotypes was observed which was more pronounced in non-meningitis cases (168%; 95%CI: 140-257) than in pneumoccocal meningitis (65%; 95%CI: 23-123). The changes in incidence after four years were: <16 years: -35% (95%CI: -49 to -19), <2 years: -46% (95%CI: -61 to -27) for pneumococcal meningitis and+11% (95%CI: -4 to +29) and -26% (95%CI: -41 to -7) for non-meningitis IPD respectively.

CONCLUSION

Infant PCV7 vaccination in Germany prompted a decrease in the incidence of pneumococcal meningitis similar to that observed in England/Wales. In non-meningitis IPD the decrease was smaller and confined to the age group <2 years with no change or an increase in incidence in other age groups pointing to potential ascertainment bias due to increased blood-culturing.

Pneumococcal disease manifestation in children before and after vaccination: what's new?

Pneumococcal infections remain a relevant cause of morbidity and mortality in children, especially in countries where vaccination has not been introduced. In contrast to the common belief by many pediatricians, the most important pneumococcal infections are of the respiratory tract and not invasive diseases. The recent pandemic of the H1N1 virus prompted studies to better understand the interaction between the influenza virus, Streptococcus pneumoniae, and pneumonia outcomes. Radiological findings of bacteremic pneumonia have been well investigated and besides the typical alveolar consolidation, a broad spectrum of atypical patterns has been reported. Molecular techniques, such as real-time polymerase chain reaction (PCR), can improve the detection of S. pneumoniae in sterile fluids, mainly in regions where previous antibiotic therapy is a common practice. In the post vaccination era, new manifestations of pneumococcal invasive disease, such as hemolytic uremic syndrome, have increased in association with parapneumonic empyema. Moreover, serotypes not included in PCV7, particularly serotypes 1, 3, 5, 7F, and 19A, have been among the most common isolates in pneumococcal disease. In Latin America, pneumococcal primary peritonitis has been described as an important clinical syndrome in a growing proportion of patients, mainly in girls. The development of newer and more specific diagnostic markers to distinguish bacterial and viral pneumonia are urgently sought, and will be especially pertinent after the introduction of pneumococcal conjugate vaccines with expanded serotypes. Such markers would minimize inappropriate diagnosis of false positive cases and treatment with antibacterial agents, while increasing positive predictive values for diagnosis of bacterial pneumonia. The extension of serotype coverage with the new conjugate vaccines is promising for pneumococcal infections and coverage against antibiotic-resistant strains.

Serotype replacement in disease after pneumococcal vaccination

Vaccination with heptavalent pneumococcal conjugate vaccine (PCV7) has significantly reduced the burden of pneumococcal disease and has had an important public health benefit. Because this vaccine targets only seven of the more than 92 pneumococcal serotypes, concerns have been raised that non-vaccine serotypes (NVTs) could increase in prevalence and reduce the benefits of vaccination. Indeed, among asymptomatic carriers, the prevalence of NVTs has increased substantially, and consequently, there has been little or no net change in the bacterial carriage prevalence. In many populations, pneumococcal disease caused by NVT has increased, but in most cases this increase has been less than the increase in NVT carriage. We review the evidence for serotype replacement in carriage and disease, and address the surveillance biases that might affect these findings. We then discuss possible reasons for the discrepancy between near-complete replacement in carriage and partial replacement for disease, including differences in invasiveness between vaccine serotypes. We contend that the magnitude of serotype replacement in disease can be attributed, in part, to a combination of lower invasiveness of the replacing serotypes, biases in the pre-vaccine carriage data (unmasking), and biases in the disease surveillance systems that could underestimate the true amount of replacement. We conclude by discussing the future potential for serotype replacement in disease and the need for continuing surveillance.

The burden of pneumococcal disease in children less than 5 years of age in Abu Dhabi, United Arab Emirates

BACKGROUND AND OBJECTIVE

Streptococcus pneumoniae is a major cause of mortality and morbidity in both developing and industrialized countries, especially among young children and in both immunocompromised and immunocompetent individuals. It is implicated in both invasive (e.g. meningitis and septicemia) as well as noninvasive disease (community-acquired pneumonia and otitis media). The objective of the current study was to describe the overall epidemiology of both invasive and noninvasive pneumococcal disease in Abu Dhabi over a 5-year period.

DESIGN AND SETTING

Retrospective review of all pediatric (≤ 5 year old) pneumococcal disease admissions to Shaikh Khalifa Medical City (SKMC) and Mafraq Hospital in Abu Dhabi from 1 January 2001 till 31 December 2005.th

METHODS

We retrieved computerized data from the health information management systems (International Classification of Diseases, 9th Revision (ICD9) diagnosis codes) as well as manual surveillance in the laboratory record of pneumococcal isolates.

RESULTS

The incidence of invasive pneumococcal disease was 13.6/100, 000 per year (95% CI, 6.5-24.9) and the incidence of noninvasive pneumococcal disease was 172.5/100,000 per year (95% CI, 143.8-205.2). The total incidence rate was 186.0/100, 000 per year (95% CI, 156.2-219.9).

CONCLUSION

This epidemiological survey indicates that the incidence rates in the United Arab Emirate are higher than in Western countries where conjugate pneumococcal vaccine has been introduced. This study is important as it documents the incidence of pneumococcal disease in the era before introduction of the conjugate pneumococcal vaccine and allows for future research to document the impact of a new vaccine considering the geographic variation of pneumococcal serotypes.

Global prevailing and emerging pediatric pneumococcal serotypes

Streptococcus pneumoniae is the leading cause of vaccine-preventable deaths among children younger than 5 years of age worldwide. The 7-valent pneumococcal conjugate vaccine (PCV7) is currently licensed in more than 90 countries and has contributed to significant declines in the incidence of invasive pneumococcal disease (IPD). Recent studies report an increased incidence of IPD caused by non-PCV7 vaccine serotypes (NVTs). Seroepidemiology of IPD caused by NVTs following the introduction of PCV7 is of interest, and this article provides a comprehensive global summary of the prevailing and emerging serotypes causing IPD in children. Currently, globally emerging or persistent NVTs include serotypes 1, 3, 5, 6A, 7F and 19A. Serotypes included in the recently licensed 10-valent pneumococcal Haemophilus influenzae protein D conjugate vaccine (PCV10) and 13-valent pneumococcal conjugate vaccine (PCV13) account for pneumococcal disease burdens in most developed countries of 65-85% and 80-90%, respectively. The seroprevalence of NVTs after widespread use of PCV10 and PCV13 requires ongoing monitoring.

[Nasopharyngeal carriage, antibiotic susceptibility and serotyping of Streptococcus pneumoniae and Haemophilus influenzae in children attending day care centers]

The aim of this study was to investigate the nasal carriage of Streptococcus pneumoniae (SP) and Haemophilus influenzae (HI) in children.

METHODS

Nasal samples were swabbed from children 3 months to 3 years of age, between December 2006 and April 2007, in 10 day-care centers in Dijon.

RESULTS

Three hundred and eighty-five children, 22.7 ± 8.4 months, were included. All were vaccinated against H1 and 92% had received at least one dose of PCV7 vaccine. HI colonization (55%) was associated with young age and concomitant pneumococcal carriage (52.4% vs. 39%). Amoxicillin/clavulanate and cefotaxime resistance rates were 17% and 0.5%. Pneumococcal carriage (48%) was increased in case of prior hospitalization. The rate of PDSP, 50%, was increased in case of recent infection (91% vs. 81%), previous antibiotherapy (64% vs. 41%), and decreased if PCV7 was completed (40.2% vs. 61,8%). There was no resistance to amoxicillin. The erythromycin resistance rate was 50.5%. 15% of the strains were vaccinal serotypes. Thirty-six and 41% of the strains were related and non-related to vaccine serotypes. Twenty-four and 11.6% of the strains were serotypes 19A and 6A respectively.

CONCLUSION

Over the last 10 years the global antibiotic resistance in children decreased for SP (22.9%) but nasal colonization remained stable due to the increase of some serotypes, such as 19A, most often resistant to antibiotics. The vaccine effectiveness against HI is optimal since no HIb serotypes were detected; resistance to betalactam is currently due equally to enzymatic mechanism and alteration of protein binding penicillin.

PneumococcaL meningitis in french children before and after the introduction of pneumococcal conjugate vaccine

In France, despite a high rate of pneumococcal conjugate vaccine coverage, the number of cases of pneumococcal meningitis in children did not decline significantly between 2001–2002 (n = 264) and 2007–2008 (n = 244). A decline was observed among children < 2 years old (185 [70.1%] to 134 [54.9%] cases; P = 0.0004), but was counterbalanced by an increase among children ≥ 2 years old (79 [29.9%] to 110 [45.1%] cases). Mean age increased significantly, from 2.3 (median 0.8) to 3.8 (median 1.5) years. After pneumococcal conjugate vaccine 7 implementation, a wide diversity of serotypes implicated in pneumococcalmeningitis was observed; serotypes 19A and 7F were the most frequent.

Rebound in the incidence of pneumococcal meningitis in northern France: effect of serotype replacement

AIM

To determine whether the recent emergence of nonvaccine pneumococcal serotypes has affected the incidence of pneumococcal meningitis in children a few years after the introduction of the heptavalent pneumococcal conjugate vaccine.

METHODS

We conducted a multicentre retrospective cohort study from 2005 to 2008 in all hospitals with paediatric units in northern France. It included all patients < 18 years of age who were admitted for laboratory-confirmed pneumococcal meningitis during the study period. Data were collected from medical files and laboratory records at each hospital and compared with the regional hospital discharge codes. We assessed global and age-specific incidence rates of pneumococcal meningitis from 2005 through 2008, compared them with those from the prevaccine era (2000-2002) and evaluated pneumococcal serotypes.

RESULTS

In all, 41 cases were found during the study period. The incidence rate of pneumococcal meningitis varied from 0.8/100,000 children < 18 years in 2005 to 1.8/100,000 children in 2008 (2.2-fold increase, p = 0.06); and from 1.8 to 11.9/100,000 children < 2 years (6.5-fold increase, p = 0.004). This increase was caused by nonvaccine pneumococcal serotypes.

CONCLUSION

The incidence of pneumococcal meningitis in infants has rebounded in northern France during the pneumococcal conjugate vaccine programme, with the emergence of nonvaccine pneumococcal serotypes.

Re-emergence of the type 1 pilus among Streptococcus pneumoniae isolates in Massachusetts, USA

Pneumococcal type 1 pilus proteins have been proposed as potential vaccine candidates. Following conjugate pneumococcal vaccination, the prevalence of the pneumococcal type 1 pilus declined dramatically, a decline associated with the elimination of vaccine-type (VT) strains. Here we show that between 2004 and 2007, there has been a significant increase in pilus prevalence, now exceeding rates from the pre-conjugate vaccine era. This increase is primarily due to non-VT strains. These emerging piliated non-VT strains are mostly novel clones, with some exceptions. The rise in pilus type 1 frequency across multiple distinct genetic backgrounds suggests that the pilus may confer an intrinsic advantage.

Early effectiveness of heptavalent conjugate pneumococcal vaccination on invasive pneumococcal disease after the introduction in the Danish Childhood Immunization Programme

We evaluated the effectiveness of the heptavalent pneumococcal conjugate vaccine (PCV7) on invasive pneumococcal disease (IPD) 1 year after PCV7's introduction in the childhood immunization programme through a nationwide cohort study based on laboratory surveillance data. There was a decline in the overall incidence of IPD from 19.4 to 17.1 cases per 100,000 population (incidence rate ratios (IRR) 0.87; 95% confidence interval (CI) [0.81-0.96]), and of meningitis from 1.56 to 1.16 (IRR 0.74; 95% CI [0.57-0.97]) comparing pre-PCV7 (years 2000-2007) and PCV7 (year 2008) periods. In children <2 years, the incidence decreased from 54 to 23 cases per 100,000 (IRR 0.43; 95% CI [0.29-0.62]) and for vaccine-serotypes from 36.7 to 7.7 (IRR 0.20; 95% CI [0.09-0.38]). The incidence of IPD declined approximately 10% (IRR 0.90; 95% CI [0.84-0.97]) in patients aged >or=2 years. The case fatality was 17% in both periods. The administration of PCV7 was followed by a marked decline in the incidence of IPD in both vaccinated and non-vaccinated individuals.

[Serotype 19F pneumococcal meningitis in an imunocompetent infant immunized with heptavalent pneumococcal conjugated vaccine Prevenar]

INTRODUCTION

Seven cases of pneumococcal meningitis caused by serotypes covered by the available vaccine occurred in France in vaccinated children, 4 of which were caused by serotype 19F.

CASE REPORT

A 3-year-old child, who had received 3 doses of the 7-valent pneumococcal conjugate vaccine Prevenar but not the 4th injection, presented with bacterial meningitis after acute media otitis. The identified bacterium was a 19F serotype of Streptococcus pneumoniae.

COMMENTS

This vaccine failure was characterized by an immune memory installation defect and underscores the necessity of the booster dose of vaccine during the 2nd year of life to acquire rates of protective and lasting antibodies. Serotype 19F of S. pneumoniae is particular since, despite good immunogenecity, it induces antibodies with weak avidity. We describe a case of pneumococcal meningitis caused by 19F serotype S. pneumoniae, which is included in the vaccine, in an immunocompetent child. Such events should be inventoried. They can reveal rates of antibodies that are very weak defenders, in spite of the vaccination, reflecting the absence of implementation of immunizing memory. Furthermore, an underlying immune deficit must be ruled out.

Reduction in the incidence of invasive pneumococcal disease after general vaccination with 7-valent pneumococcal conjugate vaccine in Germany

General vaccination with the 7-valent pneumococcal conjugate vaccine was recommended in Germany in July 2006 for all children <2 years. The proportion of reported invasive pneumococcal disease (IPD) caused by vaccine serotypes before vaccine introduction was considerably lower than in the US. We report data from nationwide surveillance of IPD in children with two reporting sources, pediatric hospitals and microbiological laboratories in Germany. Incidence rates with regard to age groups and pneumococcal serotypes are based on capture recapture estimates combining the two reporting sources. Between July 1, 1997 and June 30, 2003, 2680 cases (an average 447 yearly cases) of IPD were observed in children <16 years in Germany compared to 223 cases between July 1, 2007 and June 30, 2008. A significant reduction in overall incidence (4/100,000-3.2/100,000) was attributed to significant reductions in children younger than 2 years (20.0/100,000-11.0/100,000). While the incidence of all serotypes included in the vaccine was reduced in the age group <2 years, the incidence of non-vaccine serotypes remained stable. These data show a first success of the pneumococcal vaccination program in Germany. Further changes in incidence and serotype distribution of IPD are subject to future surveillance.

[First and second line antibiotic therapy for bacterial meningitis in infants and children]

The potential severity of meningitis in infants and children requires an optimized initial empirical therapy, mainly based on direct cerebro spinal fluid (CSF) examination, and rapid therapeutic adaptation according to bacterial identification and susceptibility. Combination treatment including cefotaxim (300 mg/kg per day) or ceftriaxone (100mg/kg per day) and vancomycine (60 mg/kg per day) remains the standard first line if pneumococcal meningitis cannot be ruled out. A simple treatment with third generation cephalosporin can be used for Neisseria meningitidis or Haemophilus influenzae meningitis, aminoglycosides must be added in case of Enterobacteriacae, mainly before 3 months of age. Second line antibiotic therapy is adapted according to the clinical and bacteriological response on Day 2. When the minimal inhibitory concentration (MIC) of pneumococcal strain is less than 0.5mg/L, third generation cephalosporin should be continued alone for a total of 10 days. In other cases, a second lumbar puncture is necessary and the initial regimen, with or without rifampicin combination, should be used for 14 days. Amoxicillin during 3 weeks, associated with gentamycin or cotrimoxazole is recommended for listeriosis.

[Corticosteroids in children with bacterial meningitis: indications and administration]

The use of dexamethasone (DXM) as adjunctive therapy for bacterial meningitis (BM) in infants and children has remained controversial for 20 years. In spite of solid pathophysiological arguments, the limited number of patients, methodological flaws in clinical studies taken individually and pooled into meta-analyses, and the emergence of pneumococcal cephalosporin-resistance did not allow to reach a consensus on the effectiveness of DXM in the prevention of neurological sequelae, in the course of non Haemophilus influenzae b (Hib) BM. A recent meta-analysis conducted with an adequate number of patients (2,750 patients including 2,074 infants and children below 15 years of age) demonstrated that DXM prevented mortality and sequelae in adults with pneumococcal meningitis and suggested that this efficacy could also apply to infants and children. Data from the active surveillance networks of pediatric BM and pneumococcal resistance in France suggested that DXM anti-inflammatory effect on antibiotic CSF penetration would not have a significant impact on the bactericidal efficacy if recommended dosages of cefotaxime (300 mg/kg per day) and vancomycin (60 mg/kg per day) were used. DXM could be considered in the early treatment of pneumococcal BM in infants and children in industrialized countries. But there is no proven efficacy of DXM in meningococcal meningitis in infants and children.

Association of serotype of Streptococcus pneumoniae with risk of severe and fatal outcome

BACKGROUND

Invasive pneumococcal disease (IPD) in children may manifest as bacteremia/sepsis, bacteremic pneumonia, or meningitis, with serious outcomes that include hospitalization, neurologic sequelae, or death. The risk of severe or fatal outcome of disease is associated with host-related factors, such as age or comorbid conditions. Furthermore, there is an ongoing discussion about organism-related factors, such as the pneumococcal serotype.

METHODS

Data on 494 children aged <16 years hospitalized for IPD between 1997 and 2003 in pediatric hospitals in Germany were analyzed. Serotype specific case-fatality rates and rates of severe outcome were compared using standardized mortality ratios (SMR). The risk of severe or fatal outcome for the serotype with the highest case-fatality rate was further analyzed using multivariate logistic regression adjusting for age younger than 1 year, meningitis, sex, and immunocompromised status as potential confounders.

RESULTS

The overall case-fatality rate was 5.3% and the rate of severe outcome was 17.0%. Serotype 7F had the highest case-fatality rate (14.8%, SMR 3.1), followed by serotypes 23F (8.3%, SMR 1.7) and 3 (8.3%, SMR 1.7). The highest rate of severe outcome was also observed for 7F (40.7%, SMR 2.4). Multivariate analysis showed an odds ratio of 4.3 (1.3-14.7) for fatal outcome and 4.0 (1.6-10.4) for severe outcome comparing 7F to all other serotypes.

CONCLUSIONS

In this study population, serotype 7F accounted for a higher risk of severe and fatal outcome than other serotypes of Streptococcus pneumoniae. In describing the epidemiology of IPD, the serotype-specific risk for severe or fatal outcome is an important complement to other serotype-specific aspects like incidence and antibiotic resistance pattern.

Invasive Streptococcus pneumoniae infections in children and older adults in the north of Spain before and after the introduction of the heptavalent pneumococcal conjugate vaccine

In the last two decades, an increasing trend in the incidence of pneumococcal disease in Europe has been reported. We investigated the effect of the use of the heptavalent pneumococcal conjugate vaccine (PCV7) in an area of northern Spain, where all recorded cases of invasive pneumococcal diseases (IPD) were included (n = 450; 91 between 1996-2007 in children aged <5 years and 359 between 1998-2007 in adults aged >64 years). All isolates were serotyped. In children, the overall IPD incidence did not significantly decrease after the introduction, in late 2001, of PCV7. However, the incidence of PCV7 serotypes significantly decreased by 137.2% from 31.59 cases/100,000 population in 1996-2001 to 13.42 in 2002-2007 (95% confidence interval [CI] -27.2 to -342.4%), as did the overall rates of penicillin resistance (from 45.6 to 18.6%) and multiresistance (from 30.3 to 11%). In older adults, the overall IPD incidence showed a non-significant increase due to non-PCV7 serotypes, which seemed to continue a previous trend in our region.

Effect of pneumococcal conjugate vaccine on pneumococcal meningitis

BACKGROUND

Invasive pneumococcal disease declined among children and adults after the introduction of the pediatric heptavalent pneumococcal conjugate vaccine (PCV7) in 2000, but its effect on pneumococcal meningitis is unclear.

METHODS

We examined trends in pneumococcal meningitis from 1998 through 2005 using active, population-based surveillance data from eight sites in the United States. Isolates were grouped into PCV7 serotypes (4, 6B, 9V, 14, 18C, 19F, and 23F), PCV7-related serotypes (6A, 9A, 9L, 9N, 18A, 18B, 18F, 19B, 19C, 23A, and 23B), and non-PCV7 serotypes (all others). Changes in the incidence of pneumococcal meningitis were assessed against baseline values from 1998-1999.

RESULTS

We identified 1379 cases of pneumococcal meningitis. The incidence declined from 1.13 cases to 0.79 case per 100,000 persons between 1998-1999 and 2004-2005 (a 30.1% decline, P<0.001). Among persons younger than 2 years of age and those 65 years of age or older, the incidence decreased during the study period by 64.0% and 54.0%, respectively (P<0.001 for both groups). Rates of PCV7-serotype meningitis declined from 0.66 case to 0.18 case (a 73.3% decline, P<0.001) among patients of all ages. Although rates of PCV7-related-serotype disease decreased by 32.1% (P=0.08), rates of non-PCV7-serotype disease increased from 0.32 to 0.51 (an increase of 60.5%, P<0.001). The percentages of cases from non-PCV7 serotypes 19A, 22F, and 35B each increased significantly during the study period. On average, 27.8% of isolates were nonsusceptible to penicillin, but fewer isolates were nonsusceptible to chloramphenicol (5.7%), meropenem (16.6%), and cefotaxime (11.8%). The proportion of penicillin-nonsusceptible isolates decreased between 1998 and 2003 (from 32.0% to 19.4%, P=0.01) but increased between 2003 and 2005 (from 19.4% to 30.1%, P=0.03).

CONCLUSIONS

Rates of pneumococcal meningitis have decreased among children and adults since PCV7 was introduced. Although the overall effect of the vaccine remains substantial, a recent increase in meningitis caused by non-PCV7 serotypes, including strains nonsusceptible to antibiotics, is a concern.

Population snapshot of Streptococcus pneumoniae serotype 19A isolates before and after introduction of seven-valent pneumococcal Vaccination for French children

Serotype 19A Streptococcus pneumoniae strains are now more frequent in French children than before the introduction of a seven-valent conjugate vaccine (PCV7). By applying multilocus sequence typing to 144 serotype 19A isolates collected before and after beginning PCV7 vaccination, we detected clonal expansion of the preexisting penicillin-intermediate sequence type 276.