Epidemiology of pneumococcal infections in French children

Epidemiology of penicillin-non-susceptible pneumococci in Iceland, 1995-2010

OBJECTIVES

The first penicillin-non-susceptible pneumococci (PNSP) were identified in Iceland in 1988. A rapid increase followed, associated with expansion of a single multiresistant clone, Spain(6B)-2, peaking at 19.8% in 1993. After interventions led to reduced antimicrobial use in children, the prevalence of PNSP decreased until 1995. The aim of this study was to follow the evolution of PNSP from 1995 to 2010, the period preceding the introduction of conjugated pneumococcal vaccines into the vaccination programme.

METHODS

The laboratory at the Landspitali University Hospital serves ∼ 85% of the Icelandic population. All pneumococci isolated from 1995 to 2010 (n = 13,937) were stored (-80 °C). Oxacillin-resistant isolates were serotyped and penicillin MICs were determined. Selected strains were genotyped by PFGE and multilocus sequence typing.

RESULTS

In 1995, the rate of PNSP was 24.2%, declining to 13.6% in 2001, and then increasing to 38.6% in 2010. Similar changes were observed for resistance to erythromycin and tetracycline. In 1995, 60.7% of PNSP were serotype 6B, mainly the Spain(6B)-2 clone, declining to 5.7% in 2010. PNSP of serotype 19F rapidly increased after 2004 to comprise 85.8% of all serogrouped PNSP in 2010, with most isolates belonging to a single multiresistant PFGE clone identified as sequence type (ST) 271 and ST1968, representing single- and double-locus variants of the international clone Taiwan(19F)-14, respectively. PNSP were most common among young children, from the nasopharynx, middle ear and lower respiratory tract.

CONCLUSIONS

The epidemiology of PNSP was dominated by two multiresistant clones. The second expanded rapidly when the first one was disappearing, causing higher antibiotic resistance rates among pneumococci than seen before in Iceland.

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.

Immunogenicity, reactogenicity, and safety of a seven-valent pneumococcal conjugate vaccine (PCV7) concurrently administered with a fully liquid DTPa-IPV-HBV-Hib combination vaccine in healthy infants

AIM OF THE STUDY

To evaluate the immunogenicity, safety and reactogenicity of a seven-valent pneumococcal conjugate vaccine (PCV7) when given concomitantly with a fully liquid DTaP-IPV-HBV-Hib combination vaccine.

METHODS

Two hundred and sixty-six healthy infants in France (n=136) and Germany (n=130) were randomized to receive DTaP-IPV-HBV-Hib and PCV7 (test group) at the age of 2, 3 and 4 months (primary series) and 12-15 months (booster dose), or to receive DTaP-IPV-HBV-Hib at the same time points but PCV7 at the ages of 5, 6, 7 and 13-16 months (control group). Antibody levels to all vaccine antigens were measured before dose 1, 1 month after dose 3, at the time of booster, and 1 month later. Safety data were collected after each vaccine dose.

RESULTS

Two hundred and fifty-seven infants (test group, 131; control group, 126) completed the primary immunization series and two hundred and forty-five received the booster dose (test group, 125; control group, 120). Depending on the serotype, 92.8-100% of subjects in the test group achieved antibody levels >or=0.15 microg/mL for PCV7 antigens at 5 months of age, and 89.7-99.1% of them antibody levels >or=0.50 microg/mL 1 month after booster. For DTaP-IPV-HBV-Hib, there was no statistically significant difference between the two groups in the proportion of infants that achieved pre-defined seroprotective levels for each antigen at 5 months and 1 month after booster. Frequency of local and systemic reactions was similar in both groups except for fever above 38.0 degrees C, which was more frequent in the test group after dose 1, 2 or 4. Fever >39.0 degrees C was only reported from three children in each group.

CONCLUSION

The PCV7 vaccine was highly immunogenic, well tolerated, and safe when coadministered with the DTPa-IPV-HBV-Hib vaccine at 2, 3, and 4 months of age and a booster dose at 12-15 months. In this study, PCV7 did not show any relevant influence on the immunogenicity and safety of the concurrently administered DTPa-IPV-HBV-Hib vaccine.

Streptococcus pneumoniae in western Europe: serotype distribution and incidence in children less than 2 years old

We did a systematic search and synthesis of evidence on the incidence of invasive pneumococcal disease, symptomatic disease, and circulating Streptococcus pneumoniae serotypes in western Europe. Using data from studies published between 1992 and 2005 we calculated a weighted mean invasive pneumococcal disease and pneumococcal meningitis incidence rate per 100,000 children aged 2 years or younger within 95% confidence intervals, together with the prevalence of S. pneumoniae serotypes and resistance to penicillin. Invasive pneumococcal disease incidence was 27.03 cases per 100,000 children under 2 years (95% CI 21.85-33.43) [corrected] Heptavalent conjugate vaccine serotypes account for 43.18-75.32% of isolates among people aged under 18 years of age. 11% of isolates in individuals aged under 18 years were penicillin resistant. The incidence of invasive pneumococcal disease appeared consistently lower in western European countries compared with studies from the USA. Thus the use of studies of vaccine effectiveness based on the US population may lead to an overestimation of the benefits of its introduction in Europe.

[Clinical effectiveness of seven-valent pneumococcal conjugate vaccine (Prevenar) against invasive pneumococcal diseases: prospects for children in France]

A seven-valent pneumococcal polysaccharide-CRM197 carrier protein conjugate vaccine (PNC7V; Prevenar, Wyeth, Paris) targets the serotypes (belonging to serogroups 14, 6, 19, 18, 23, 9, and 4) most often responsible for invasive pneumococcal disease (IPD) among children. A randomized, controlled, double-masked study among 37,868 children in northern California (Northern California Kaiser Permanente, USA) provided a per protocol vaccine efficacy value of 97.7% against invasive pediatric IPD due to the vaccine serotypes. The PNC7V vaccine was registered by the European Agency for the Evaluation of Medicinal Products (EMEA) in October 2000; a favorable "Community Marketing Decision" under the Centralized Procedure was granted in February 2001. PNC7V was recommended for most infants by the Conseil Supérieur d'Hygiène Publique de France in March 2002, on the advice of the Comité Technique des Vaccinations, as S. pneumoniae in children less than 2 years of age is the primary cause of bacterial meningitis and of mortality associated with community-acquired bacterial infections. The theoretical coverage of the vaccine towards pneumococcal invasive disease in France is about 80%, which represents one of the best serotype coverage estimates in Europe, and vaccines serotypes account for 90% of penicillin-nonsusceptible strains. Distinctive characteristics in France in terms of epidemiology, life style, and therapeutic attitudes justify a precise follow up of the consequences of the vaccination on a national level during the coming years. Hence, surveillance programs have been established: (i) to ascertain the future impact of large-scale PNC7V vaccination on invasive pneumococcal disease incidence, (ii) to follow the evolution of carriage and ecology of the pneumococcus, and (iii) to establish an active "vaccinovigilance".

Tolérance et immunogénicité d’un vaccin pneumococcique osidique conjugué heptavalent (Prevenar®) administré en association avec une combinaison vaccinale pédiatrique (DTCoq-Polio/Hib) à des nourrissons selon le schéma vaccinal français à l’âge de deux, trois et quatre mois

Invasive pneumococcal disease is presently a leading cause of mortality due to bacterial infectious diseases in French children less than 2 years of age, and only the pneumococcal conjugate vaccines induce a protective immune response for those within this vulnerable age group.

MATERIAL AND METHODS

The safety and immunogenicity of a heptavalent pneumococcal polysaccharide conjugate vaccine (PREVENAR was tested in French infants immunized with the 2, 3 and 4 month French schedule as part of an open, randomized, comparative clinical study, in association with a whole-cell pertussis-based pediatric combination vaccine.

RESULTS

In the PREVENAR plus DTP-IPV/Hib association group, 90.6-100% of children achieved a post-dose three threshold IgG concentration of >0.15 microg/ml against each of the seven pneumococcal serotypes. Regarding immunogenicity, no interference with the antibody response to the various antigenic components of the DTP-IPV/Hib vaccine was observed. Local reactions were significantly less frequent at the PREVENAR injection site than at the DTP-IPV/Hib injection site; there was no increase in systemic adverse events in the vaccine association group compared to the DTP-IPV/Hib alone group, further exception of fever >38 degrees C which was more frequently reported in the PREVENAR + PENTACOQ group following the second dose of vaccines (56% vs. 35%); no serious adverse event could be considered to be related to the PREVENAR immunization in this study.

CONCLUSION

The heptavalent pneumococcal conjugate vaccine is immunogenic when administered at 2, 3 and 4 months. PREVENAR can be administered simultaneously with the DTP-IPV/Hib combination vaccine.

[Survey of the judicious use of antibiotics in primary care]

OBJECTIVE

To identify pediatricians' antibiotic prescribing habits in acute otitis media and tonsillopharyngitis and to determine the interaction between parents and pediatricians concerning antibiotic use in the Autonomous Community of Valencia (Spain).

METHOD

Four hundred members of the Valencian Society of Pediatrics were randomly selected. A semi-structured questionnaire with non-excluding answers was sent by mail and, when responses were not obtained, a second one was sent. The confidentiality of the information was guaranteed.

RESULTS

Of 400 questionnaires sent, 143 (35.8 %) were completed; 88.1 % were completed by pediatricians and 51.1 % by primary care workers. A total of 48.3 % of pediatricians used antibiotics in all cases of acute otitis media and 94.5 % prescribed them when fever and otalgia persisted for more than 48 hours. Amoxicillin-clavulanate was the most frequently prescribed antibiotic (63.6 %). Less than 10 % of pediatricians prescribed antibiotics as empirical treatment in tonsillopharyngitis; amoxicillin was the most frequently prescribed antibiotic (54.6 %). Indications for antibiotic treatment were fever, odynophagia and adenomegaly (69.5 %) and tonsillar exudate (62.5 %). Inappropriate antibiotic use was mainly due to excess workload. Providing health education to parents could be the best way of reducing inappropriate use.

CONCLUSIONS

Antibiotic use is frequent in the treatment of acute otitis media. Amoxicillin-clavulanate and amoxicillin were the most frequently prescribed antibiotics in tonsillopharyngitis. Providing health education to parents and reducing pediatricians' workload would decrease inappropriate antibiotic use.

[Role of pneumococcus in pediatric infectious pathology]

Streptococcus pneumoniae is the most common bacterial cause of invasive and non-invasive infections in children of less than two years. The high level of resistance to penicillin and other antimicrobial agents observed particularly in France is responsible of the difficulties concerning the treatment of acute otitis media and meningitis due to S. pneumoniae. Potential positive consequences of the implementation of pneumococcal conjugate vaccine may include prevention of invasive diseases and prevention of spread of the drug resistant-strains.