Streptococcus pneumoniae in children in Spain: 1990-1999

PCV15, a pneumococcal conjugate vaccine, for the prevention of invasive pneumococcal disease in infants and children

INTRODUCTION

Streptococcus pneumoniae is a causative agent of pneumonia and acute otitis media (AOM), as well as invasive diseases such as meningitis and bacteremia. PCV15 (V114) is a new 15-valent pneumococcal conjugate vaccine (PCV) approved for use in individuals ≥6 weeks of age for the prevention of pneumonia, AOM, and invasive pneumococcal disease.

AREAS COVERED

This review summarizes the V114 Phase 3 development program leading to approval in infants and children, including pivotal studies, interchangeability and catch-up vaccination studies, and studies in at-risk populations. An integrated safety summary is presented in addition to immunogenicity and concomitant use of V114 with other routine pediatric vaccines.

EXPERT OPINION

Across the development program, V114 demonstrated a safety profile that is comparable to PCV13 in infants and children. Immunogenicity of V114 is comparable to PCV13 for all shared serotypes except serotype 3, where V114 demonstrated superior immunogenicity. Higher immune responses were demonstrated for V114 serotypes 22F and 33F. Results of the ongoing study to evaluate V114 efficacy against vaccine-type pneumococcal AOM and anticipated real-world evidence studies will support assessment of vaccine effectiveness and impact, with an additional question of whether higher serotype 3 immunogenicity translates to better protection against serotype 3 pneumococcal disease.

Epidemiology of pneumococcal diseases in Spain after the introduction of pneumococcal conjugate vaccines

In Spain, the use of pneumococcal conjugate vaccines (PCVs) has led to a decrease in the incidence of vaccine serotypes causing invasive and non-invasive disease in vaccinated and unvaccinated children and adults. Further, the coverage of most of the resistant serotypes by vaccines resulted in an overall decline in antibiotic resistance. As an undesirable effect, there was an increase in the non-vaccine serotypes causing infection, especially serotypes 1, 7F and 19A after PCV7 and serotype 8 after PCV13 approval, this making the beneficial effect of vaccination less apparent. The inclusion of PCVs in childhood vaccination schedules, its approval for use in healthy adults and the increasing number of serotypes covered by the vaccines in development are strong strategies in the fight against pneumococcal disease. Nonetheless, the epidemiology of Streptococcus pneumoniae infections must be still under surveillance to detect new changes, given the high capacity for recombination and adaptability of this always-surprising microorganism.

Upper respiratory tract microbial communities, acute otitis media pathogens, and antibiotic use in healthy and sick children

The composition of the upper respiratory tract microbial community may influence the risk for colonization by the acute otitis media (AOM) pathogens Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis. We used culture-independent methods to describe upper respiratory tract microbial communities in healthy children and children with upper respiratory tract infection with and without concurrent AOM. Nasal swabs and data were collected in a cross-sectional study of 240 children between 6 months and 3 years of age. Swabs were cultured for S. pneumoniae, and real-time PCR was used to identify S. pneumoniae, H. influenzae, and M. catarrhalis. The V1-V2 16S rRNA gene regions were sequenced using 454 pyrosequencing. Microbial communities were described using a taxon-based approach. Colonization by S. pneumoniae, H. influenzae, and M. catarrhalis was associated with lower levels of diversity in upper respiratory tract flora. We identified commensal taxa that were negatively associated with colonization by each AOM bacterial pathogen and with AOM. The balance of these relationships differed according to the colonizing AOM pathogen and history of antibiotic use. Children with antibiotic use in the past 6 months and a greater abundance of taxa, including Lactococcus and Propionibacterium, were less likely to have AOM than healthy children (odds ratio [OR], 0.46; 95% confidence interval [CI], 0.25 to 0.85). Children with no antibiotic use in the past 6 months, a low abundance of Streptococcus and Haemophilus, and a high abundance of Corynebacterium and Dolosigranulum were less likely to have AOM (OR, 0.51; 95% CI, 0.31 to 0.83). An increased understanding of polymicrobial interactions will facilitate the development of effective AOM prevention strategies.

Relationship between serotypes, age, and clinical presentation of invasive pneumococcal disease in Madrid, Spain, after introduction of the 7-valent pneumococcal conjugate vaccine into the vaccination calendar

To assess invasive pneumococcal disease (IPD) clinical presentations and relationships with age and serotype in hospitalized children (<15 years) after PCV7 implementation in Madrid, Spain, a prospective 2-year (May 2007 to April 2009) laboratory-confirmed (culture and/or PCR) IPD surveillance study was performed (22 hospitals). All isolates (for serotyping) and culture-negative pleural/cerebrospinal fluids were sent to the reference laboratory for pneumolysin (ply) and autolysin (lyt) gene PCR analysis. A total of 330 IPDs were identified: 263 (79.7%) confirmed by culture and 67 (20.3%) confirmed by PCR. IPD distribution by age (months) was as follows: 23.6% (<12), 15.8% (12 to 23), 15.5% (24 to 35), 22.4% (36 to 59), and 22.7% (>59). Distribution by clinical presentation was as follows: 34.5% bacteremic pneumonia, 30.3% pediatric parapneumonic empyema (PPE), 13.6% meningitis, 13.3% primary bacteremia, and 8.2% others. Meningitis and primary bacteremia were the most frequent IPDs in children <12 months old, and bacteremic pneumonia and PPE were most frequent in those >36 months old. Frequencies of IPD-associated serotypes were as follows: 1, 26.1%; 19A, 18.8%; 5, 15.5%; 7F, 8.5%; 3, 3.9%; nontypeable/other 30 serotypes, 27.3%. Serotype 1 was linked to respiratory-associated IPD (38.6% in bacteremic pneumonia and 38.0% in PPE) and children of >36 months (51.4% for 36 to 59 months and 40.0% for >59 months), while serotype 19A was linked to nonrespiratory IPDs (31.1% in meningitis, 27.3% in primary bacteremia, and 51.9% in others) and children of <24 months (35.9% for children of <12 months and 36.5% for those 12 to 23 months old), with high nonsusceptibility rates for penicillin, cefotaxime, and erythromycin. After PCV7 implementation, non-PCV7 serotypes caused 95.5% of IPDs. The new 13-valent conjugate vaccine would provide 79.1% coverage of serotypes responsible for IPDs in this series.

Pediatric parapneumonic pleural effusion: epidemiology, clinical characteristics, and microbiological diagnosis

BACKGROUND

In recent years an increase in the incidence and severity of parapneumonic pleural effusion (PPE) in pediatric populations has been observed. Streptococcus pneumoniae remains the main causal agent. New molecular and antigen techniques have increased the microbiological diagnosis of this pathology.

OBJECTIVES

To describe the epidemiology and clinical characteristics of PPE in our population.

PATIENTS AND METHODS

Prospective study of patients under the age of 18 years admitted for PPE in a tertiary-care pediatric hospital in Barcelona (Spain) between September 2003 and December 2006.

RESULTS

One hundred ninety cases of PPE were diagnosed. The annual incidence of PPE in the population under 18 years of age increased from 19.9 cases per 100,000 in 2004 to 35.2 per 100,000 in 2006. S. pneumoniae was the main causal agent identified: 82.9% of the 21.6% patients with positive culture. Non-vaccine serotypes (NVS) predominated (81.5%), and serotype 1 was responsible for 38.5% of cases. The use of polymerase chain reaction (PCR) test to detect S. pneumoniae increased etiological diagnosis from 21.6% to 42.1%. Antigen assays used to detect pneumococcus in pleural fluid demonstrated 87.9% sensitivity and 100% specificity when PCR was used as the gold standard.

CONCLUSIONS

There has been an increase in the incidence of PPE that parallels the increase in CAP. S. pneumoniae remains the principal causal agent, and NVS clearly predominate. The use of PCR to detect S. pneumoniae substantially increases etiologic diagnosis. The use of antigen assays to detect pneumococcus in pleural fluid is a quick and sensitive diagnostic method, and thus a valid alternative to PCR.

Global serotype distribution among Streptococcus pneumoniae isolates causing otitis media in children: potential implications for pneumococcal conjugate vaccines

Acute otitis media (AOM) is the most common infection following pneumococcal colonization of the upper respiratory tract. Streptococcus pneumoniae causes 30-60% of AOM cases worldwide. However, not all pneumococcal serotypes cause disease and an association exists with nasopharyngeal colonization by certain serotypes and their propensity to cause AOM. This review examines the global serotype distribution relationship between pneumococcal serotypes and AOM in children aged <18 years and demonstrates that the most common pneumococcal serotypes causing AOM globally are 3, 6A, 6B, 9V, 14, 19A, 19F, and 23F.

Trends in incidence of pneumococcal disease before introduction of conjugate vaccine: South West England, 1996-2005

Introduction of pneumococcal conjugate and polysaccharide vaccines into the United Kingdom's routine immunization programmes is expected to change the epidemiology of invasive pneumococcal disease (IPD). We have documented the epidemiology of IPD in an English region (South West) with high-quality surveillance data before these programmes were established. We analysed data on isolates of Streptococcus pneumoniae from blood and CSF between 1996 and 2005 from microbiology laboratories in the South West that were reported and/or referred for serotyping to the Health Protection Agency Centre for Infections. The mean annual incidence of IPD increased from 11.2/100 000 in 1996 to 13.6/100 000 in 2005 (P<0.04). After adjusting for annual blood-culture sampling rates in hospitals serving the same catchment populations, an increase in annual incidence of IPD was no longer observed (P=1.0). Variation in overall incidence between laboratories could also be explained by variation in blood culture rates. The proportion of disease caused by serotypes 6B, 9V and 14 decreased significantly (P=0.001, P=0.007, and P=0.027 respectively) whereas that caused by serotype 4, 7F and 1 increased (P=0.001, P=0.003, and P<0.001 respectively) between 2000 and 2005. The level of penicillin non-susceptibility and resistance to erythromycin remained stable (2% and 12% respectively). This study provides an important baseline to assess the impact of changing vaccination programmes on the epidemiology of IPD, thus informing future use of pneumococcal vaccines.

Antimicrobial susceptibility of Streptococcus pyogenes and Streptococcus pneumoniae: surveillance from 1993 to 2004 in Central Italy

The susceptibility of 1870 Streptococcus pyogenes and 1595 Streptococcus pneumoniae to macrolides and lincosamides has been monitored from 1993 to 2004 in Central Italy. Among S. pyogenes, 30.2% were erythromycin resistant; 18.5% were also resistant to josamycin and clindamycin (MLS phenotype). After an increasing erythromycin resistance rate in 1993-1997 (maximum 53.16%), a definite decrease was observed since 2001 with resistance rates always less than 30%. Thirty six percent of pneumococcal isolates were erythromycin-resistant, with minor temporal fluctuations; the MLS phenotype was the most prevalent overall (32.6%) and in individual years. S. pneumoniae strains were also tested for susceptibility to beta-lactams and other antimicrobial agents: 11.2% were penicillin non-susceptible, with a gradually increasing prevalence after 2001 (maximum rate 17.3% in 2004), 31.15% were resistant to tetracycline, 4.9% to chloramphenicol, 0.74% to rifampin. All pneumococcal isolates were susceptible to teicoplanin and 99.9% to ceftriaxone and ofloxacin.

Burden of paediatric invasive pneumococcal disease in Europe, 2005

Within the European Union (EU), documenting the burden of invasive pneumococcal disease (IPD) in infants and children is important for coordinating effective pneumococcal immunization policies. Our objective was to document the burden of IPD in countries of the EU plus Switzerland and Norway. European affiliates of Wyeth Vaccines made available recent epidemiological data on IPD from local disease surveillance programmes, including unpublished sources. Recent literature and websites were also searched to provide as wide a representation as possible. This included OVID and abstracts from a number of international meetings, dating from the year 2000. The reported rates of paediatric IPD per 100000 (age) ranged from a low of 1.7 (<2 years) to 4.2 (2-15 years) in Sweden to a high of 93.5 to 174 (<2 years) to 56.2 (<5 years) in Spain. The percentage of circulating serotypes causing IPD that are covered by 7-valent pneumococcal conjugate vaccine (PCV) IPD serotype coverage ranged from 60% to 80% for European children aged <2 years. Under reporting, differences in reporting methods, antibiotic prescribing and disparities in blood-culturing practices may explain the differences in reported disease incidence. Because of the excellent clinical efficacy of the PCV against IPD, national pneumococcal vaccination programmes in Europe have the potential to prevent much morbidity and mortality.

Clinical data and factors associated with poor outcome in pneumococcal meningitis

We carried out a 4-year study of 159 children (ages 1 month-14 years) with pneumococcal meningitis. The study was divided into two periods: the retrospective period (1998-2000: 107 patients), and the prospective period (2001-2002: 52 patients). About 2/3 of the children were under 2 years of age: 72 (45%) were under 1 year of age and 38 (24%) had meningitis during the second year of life. One-third of the patients had signs of otitis media; convulsions were more frequent in patients under 1 year compared with older patients (34.7 vs. 14.9%; P=0.004); 13/159 children (8.2%) died; 93/159 (58.5%) recovered completely, 12.6% had motor sequelae, 6.9% hydrocephalus, 29.8% sensorineural hearing loss; 140/159 (88%) were treated with third generation cephalosporins, yet only 8.7% of the pneumococci identified were completely penicillin-resistant (> or =1 microg/ml); 119/159 were treated with dexamethasone. Four patients had received an injection of heptavalent vaccine. Antibiotics for 1 week prior to admission, shock, abnormal pupils, leukocytes count <6,000 mm(3), and CSF glucose < or =8.5 mg/dl were significantly associated with poor outcome and/or death in the univariate analysis. No patient with leukocytosis >16,000/mm(3) died. Conclusion. Sequelae are very common in pneumococcal meningitis. Poor outcome was associated with pupillary abnormality and a leukocyte count <6,000/mm(3) on admission. Leukocytosis was protective against poor outcome.

Derrame pleural paraneumónico: revisión de 11 años

INTRODUCTION

In the last few years, the incidence of parapneumonic effusions in children with community-acquired pneumonia seems to have increased. The aim of this study was to determine the clinical features and incidence of parapneumonic effusions throughout an 11-year period.

MATERIAL AND METHODS

We retrospectively reviewed the medical records of patients aged < 15 years old with parapneumonic effusions from 1993 to 2003. Annual incidence rates were calculated per 100,000 children < 15 years old from Health Area 5 of Madrid and per 100 children hospitalized in the Infectious Diseases Department of our hospital. The linear association test was used to compare the incidence rates over the previous 11 years.

RESULTS

There were 130 patients with parapneumonic pleural effusions. The mean age was 4.7 years. Forty-one percent received antibiotics before diagnosis. The causative organisms were identified in 42 patients (32.3%). The most effective diagnostic method was pleural-fluid culture (18/58, 31%). The most common organisms were Streptococcus pneumoniae (18), Mycoplasma pneumoniae (8), Staphylococcus aureus (4), Streptococcus pyogenes (3), Haemophilus influenzae (3) and Mycobacterium tuberculosis (2). Thirty-two percent of the patients required pleural drainage and 16% underwent video-assisted thoracoscopic surgery. Of 12 S. pneumoniae antibiograms available, 91.7% showed full susceptibility to penicillin and 75% were susceptible to erythromycin. The annual incidence of parapneumonic effusions rose from 18.1 in 1993 to 42.9 in 2003 (p < 0.001) per 100,000 children and from 0.76 in 1993 to 3.3 in 2003 (p < 0.001) per 100 children hospitalized in our unit.

CONCLUSION

The incidence of parapneumonic effusions in children with community-acquired pneumonia showed a statistically significant increase between 1993 and 2003. The most common causal organism was S. pneumoniae, with a low rate of penicillin resistance.

Analysis of the genetic structure of nontypeable pneumococcal strains isolated from conjunctiva

More than 50% of the nontypeable (NT) pneumococcal strains received in our laboratory for reference purposes are isolated in sporadic cases of conjunctivitis. To determine the genetic structure of the population of these NT conjunctival strains, we analyzed 75 pneumococci (40 NT and 35 typeable) isolated from conjunctivas and 30 (15 NT and 15 typeable) isolated from other sources. The NT and typeable conjunctival strains grouped in separate clusters, whereas NT and typeable pneumococci isolated from other sources were similarly distributed. NT conjunctival strains belonged to two well-differentiated clonal lineages. The first, represented by three newly described sequence types, featured fully antibiotic susceptible strains and appeared to be characteristic of conjunctival tissue; the second, represented by the previously described ST344, had a pattern of multiresistance to penicillin, tetracycline, and erythromycin and shared a genetic background with some NT strains isolated from other sources.

[Etiology of acute otitis media in a children's hospital and antibiotic sensitivity of the bacteria involved]

BACKGROUND

This study provides an update on the bacterial etiology of acute otitis media in our area, the antibiotic sensitivity of the bacteria implicated in this condition, and the prevalence of circulating Streptococcus pneumoniae serotypes.

METHODS

Results from a total of 240 samples obtained by diagnostic tympanocentesis and 167 samples of spontaneous otorrhea processed between 1999 and 2001 were reviewed retrospectively.

RESULTS

The mean age of the patients studied was 17 months and the median was 13 months (range: 1 month-7 years). Among the tympanocentesis samples, S. pneumoniae was recovered from 67 (27.9%), Haemophilus influenzae from 60 (25%), both S. pneumoniae and H. influenzae from 3 (1.3%) and Moraxella catarrhalis from 6 (2.5%). Among the spontaneous otorrhea samples, S. pneumoniae was recovered from 15 (9%), H. influenzae from 25 (15%) and both S. pneumoniae and H. influenzae from 1 (0.6%). The remaining samples showed either no growth or recovery of colonizing flora. The main findings were as follows: 49.3% of S. pneumoniae strains showed intermediate sensitivity to penicillin (MIC: 0.12-1 microg/ml), 16.9% were resistant to penicillin (MIC: > or = 2 microg/ml) and 54% were resistant to macrolides; 24,7% of H. influenzae and 100% of M. catarrhalis strains were beta-lactamase producers; and 64 (84.2%) of 76 S. pneumoniae serotyped strains belonged to pneumococcal heptavalent vaccine serotypes.

CONCLUSIONS

S. pneumoniae and H. influenzae were the main causal agents of acute otitis media. Antibiotic sensitivity of the bacteria involved showed the same characteristics as the general pattern in our country. Spontaneous otorrhea culture was not a useful method for establishing the etiology of acute otitis media. Knowledge of the distribution of S. pneumoniae serotypes is essential for assessing epidemiological changes resulting from the use of heptavalent pneumococcal vaccine.

Characterisation of invasive pneumococcal isolates in Catalan children up to 5 years of age, 1989–2000

Ninety-six Streptococcus pneumoniae strains isolated between January 1989 and December 2000 from usually sterile sites of children aged < 5 years of age were included in the study. Resistance to penicillin (38.6% intermediate, 10.4% high-level), cefotaxime (20.8%), tetracycline (41.7%), chloramphenicol (33.3%) and erythromycin (27.1%), as well as serogroup/type, were related to age and pathology. Strains from children aged < 2 years showed the highest penicillin resistance rate. Resistance to penicillin, tetracycline, chloramphenicol and erythromycin was the most common pattern (18.8% of strains). Most isolates (80.2%) belonged to serogroups/types included in the heptavalent conjugate vaccine.

Calendario vacunal de la Asociación Española de Pediatría: recomendaciones 2004

The Vaccine Assessment Committee of the Spanish Association of Pediatrics discusses vaccine developments in 2003 and recommends some modifications to the vaccination schedule. The recommendation of substituting the oral polio vaccine for the inactivated polio vaccine, suppressing the fifth dose, is maintained. The introduction of the conjugate pneumococcal vaccine and the varicella vaccine is stressed. Concerning the meningococcal C vaccine, the improvement introduced by being able to immunize with just two doses is discussed. In agreement with the information received from the European Medicines Agency, there appear to be no well-founded reasons to abandon hexavalent preparations.

A pharmacoeconomic evaluation of seven-valent pneumococcal conjugate vaccine in Spain

BACKGROUND

Streptococcus pneumoniae is a leading cause of illness in children. Seven-valent pneumococcal conjugate vaccine (PCV-7), recently approved in the United States, is the first vaccine to provide protective immunity against pneumococcal disease in children under the age of 2. PCV-7 is nearly 100% effective in preventing invasive pneumococcal infections and has been shown to significantly decrease the incidence of pneumonia and otitis media.

OBJECTIVE

The objective of this study was to evaluate the health outcomes, costs, and cost-effectiveness of vaccination with PCV-7, compared with no vaccination for children in Spain.

METHODS

A health state model was used to determine the health and economic outcomes in vaccinated and unvaccinated groups among children less than 5 years old. This analysis was conducted for a 10-year time horizon, beginning with initial vaccinations. Information on the burden of pneumococcal disease, in terms of data on the incidence and seroprevalence of disease, was collected from published and unpublished records, supplemented, and verified by Spanish pediatric and infectious disease experts. The efficacy of PCV-7 was based on updated findings of the Kaiser Permanente Efficacy Study. A cost-of-illness estimate for each pneumococcal disease was determined using decision tree analysis that considered direct and indirect costs. A birth cohort analysis compared the expected cost of vaccinated populations to age-matched unvaccinated populations.

RESULTS

Implementing a PCV-7 vaccine program in Spain in a birth cohort of 360000 is expected to save approximately 16 lives and 132000 cases of pneumococcal disease over 10 years, resulting in total savings estimated at Euros 81 million (ESP13.5 billion), of which Euros 43.5 million (ESP7.1 billion) are direct medical savings. At a vaccine cost up to Euros 56.87 per dose (ESP9,462, the total cost of vaccinating a birth cohort of 360000 will be offset by the total savings owing to reduced morbidity.

CONCLUSIONS

Implementing a universal PCV-7 vaccination program in Spain will significantly decrease the mortality and morbidity associated with pneumococcal infections in young children. At an assumed cost of Euros 48.56 (ESP8080) per dose, PCV-7 vaccination of Spanish children under the age of 5, followed over a 10-year period, is cost saving from the societal perspective and cost-effective from the payer perspective at Euros 22500 per LYG (ESP3,734713), comparing favorably with other preventive programs in Spain.

Enfermedad neumocócica invasiva en la población infantil de la Comunidad Valenciana

OBJECTIVE

Pneumococcal disease is an important cause of morbidity and mortality in children. The recent authorization of the heptavalent conjugate vaccine has increased interest in this disease. The objective of this study was to identify the epidemiological and clinical characteristics of this disease, as well as its outcome in the pediatric population of the Autonomous Community of Valencia.

METHOD

Data were obtained from the medical records of children aged less than 15 years who were positive for pneumococcus isolation on admission to hospital between 1996 and 2000. All the public hospitals of the Autonomous Community of Valencia were included. Changes in incidence were evaluated by comparing rates and outcomes (sequelae and lethality) through frequency and age distribution.

RESULTS

One hundred twenty-seven cases were registered, giving a mean annual rate of 3.89/105 inhabitants aged less than 15 years. The rate was 20.14 in children aged less than 2 years. A total of 29.1% of the children had previous health problems. The main clinical manifestations included sepsis/bacteremia (38%), pneumonia (31%) and meningitis (24%). At discharge sequelae were present in 10 children, 75% of whom were aged less than 2 years. Eight children died (6.3% lethality).

CONCLUSIONS

In the period and region studied, pneumococcal infection was present mainly in children aged less than 2 years and in those with previous health problems. In the last few years, mortality has increased. Thus, inclusion of pneumococcal disease in the epidemiological surveillance system would be appropriate to achieve more precise estimations of its epidemiological patterns and to determine whether the conjugate vaccine represents a solution to the problems currently associated with this bacteria.

Incidencia de enfermedad neumocócica invasiva en Cantabria (1995-2001) e implicaciones para el calendario vacunal

OBJECTIVE

To describe the incidence of invasive pneumococcal disease in Cantabria (Spain) between 1995 and 2001.

METHOD

We reviewed the records of the Minimum Data Set (MDS) of public hospitals in Cantabria, discharges from private hospitals and the registry of diseases of mandatory reporting, as well as the microbiologic diagnoses and medical records of children discharged from the Pediatric Service of the Cantabria Hospital (the tertiary care hospital in our autonomous community).

RESULTS

We obtained a meningitis incidence of 5.55, 5.03 and 0.76/100,000 in children < 2 years, > or = 2 and < 5 years, and > or = 5 years respectively, and an incidence of invasive disease of 11.11, 11.32 and 1.49/100,000 in the same age groups.

CONCLUSIONS

The incidence of meningitis and invasive pneumococcal disease in Cantabria is low. We discuss factors that should be taken into account when introducing the pneumococcal conjugate vaccine in the childhood immunization schedule of Cantabria.

Prediction of the potential benefit of different pneumococcal conjugate vaccines on invasive pneumococcal disease in German children

BACKGROUND

In the US a pneumococcal conjugate vaccination program with a 7-valent conjugate vaccine was successfully implemented in 2000. How much invasive pneumococcal disease can potentially be prevented by the 7-valent (or 11-valent) vaccine in Europe?

METHODS

Prospective, active surveillance of invasive pneumococcal disease in German children age <16 years was performed between 1997 and 2000. Age- and disease-specific coverage and incidence rates were assessed in children old enough to benefit from complete vaccination to estimate the annual number of cases potentially preventable.

RESULTS

A total of 1,743 cases were reported; 667 isolates were serotyped. Coverage of 7-valent (11-valent) conjugate vaccines in children age 6 months and older was age- and diagnosis-dependent, ranging from 10.5% (15.8%) to 78.3% (82.6%) for meningitis and from 13.6% (68.2%) to 75.0% (89.3%) for nonmeningitis invasive pneumococcal disease cases. Of an estimated annual number of 176 children with pneumococcal meningitis age 6 months or older, 112 (122) cases had serotypes included in the 7-valent (11-valent) conjugate vaccine compared with 181 (254) of 324 nonmeningitis invasive pneumococcal disease cases, with 37 of the 73 cases covered by the 11-valent vaccine only in children older than 5 years. Regarding meningitis in this age group the potential benefit was equally poor for both the 7-valent (12 of 37 cases) and the 11-valent vaccine (15 of 37 cases).

CONCLUSION

Coverage of the 7- and 11-valent conjugate vaccines depends markedly on age and disease. The additional potential benefit of the 11-valent compared with the 7-valent vaccine for pneumococcal meningitis was marginal.

[Invasive pneumococcal disease in children in the region of Murcia (Spain)]

OBJECTIVE

Because of the availability of a conjugate pneumococcal vaccine, the incidence and characteristics of invasive pneumococcal disease in children in the region of Murcia should be determined. This would provide information that could be useful for properly establishing the indications for vaccination.

METHODS

A retrospective search was conducted for cases of invasive Streptococcus pneumoniae in children aged less 15 years old treated in hospitals in Murcia from 1991-2000. The data sources were the databases of the microbiology services, the Minimum Data Set, the Pediatric Admissions Register and the EDO Register.

RESULTS

The incidence rate for the period 1996-2000 was 18.25 per 105 children per year for children aged under 1 year in the case of invasive disease (10.6 for meningitis), 13.6 for those under 2 years for invasive disease (6 for meningitis), 8.9 for those under 5 years (1.35 for meningitis) and 3.7 for those under 15 years (1.3 for meningitis). Twenty-eight percent of the patients presented risk factors. Complications occurred in 35.2% and sequelae occurred in 5%. The mortality rate was 11.8%. The prevalent serogroups were 19, 6, 18, 5, 14 and 23.

CONCLUSIONS

The high percentage of patients with risk factors for invasive pneumococcal disease suggests the need to implement vaccination programs aimed at risk groups. Although the incidence of invasive pneumococcal disease in the region of Murcia differs from that in other areas, the incidence of meningitis is similar to that reported by other studies. Because of the severity of the disease, cost-effectiveness studies to evaluate the possible incorporation of the vaccine in the vaccination calendar are justified.

Effects of specific antibodies against Streptococcus pneumoniae on pharmacodynamic parameters of beta-lactams in a mouse sepsis model

A dose-ranging study to investigate the in vivo effects of the presence of specific antibodies on the efficacy of beta-lactam treatment of sepsis caused by Streptococcus pneumoniae (non-beta-lactam-susceptible serotype 6B isolate) was performed with a BALB/c mouse model. Hyperimmune serum was obtained from mice immunized with the heat-inactivated strain. The rate of mortality was 100% in nontreated animals in the absence of specific antibodies. A single injection of a one-half or one-quarter dilution of hyperimmune serum produced 60 to 40% survival rates. In the absence of specific antibodies, the minimal effective doses of amoxicillin and cefotaxime that produced survival rates of 100 and 80% were 25 and 50 mg/kg of body weight (three times a day for up to six doses), respectively. These doses produced times that the levels in serum remained above the MIC (deltaT > MICs) approximately 30% of the dosing interval. When specific antibodies were present (by administration of a one-half or one-quarter dilution of hyperimmune serum), the minimal effective doses of the antibiotics were 3.12 and 6.25 mg/kg ( approximately 8 times lower), with the deltaT > MICs being approximately 3 and 5% of the dosing interval for amoxicillin and cefotaxime, respectively. This in vivo combined pharmacodynamic effect offers possibilities that can be used to address penicillin resistance.