Pneumococcal Conjugate Vaccine In Children Research Articles

Colonisation by Streptococcus pneumoniae and Staphylococcus aureus in healthy children

A trial with a 7-valent pneumococcal-conjugate vaccine in children with recurrent acute otitis media showed a shift in pneumococcal colonisation towards non-vaccine serotypes and an increase in Staphylococcus aureus-related acute otitis media after vaccination. We investigated prevalence and determinants of nasopharyngeal carriage of Streptococcus pneumoniae and S aureus in 3198 healthy children aged 1-19 years. Nasopharyngeal carriage of S pneumoniae was detected in 598 (19%) children, and was affected by age (peak incidence at 3 years) and day-care attendance (odds ratio [OR] 2.14, 95% CI 1.44-3.18). S aureus carriage was affected by age (peak incidence at 10 years) and male sex (OR 1.46, 1.25-1.70). Serotyping showed 42% vaccine type pneumococci. We noted a negative correlation for co-colonisation of S aureus and vaccine-type pneumococci (OR 0.68, 0.48-0.94), but not for S aureus and non-vaccine serotypes. These findings suggest a natural competition between colonisation with vaccine-type pneumococci and S aureus, which might explain the increase in S aureus-related otitis media after vaccination.

Impact of childhood vaccination on racial disparities in invasive Streptococcus pneumoniae infections.

Historically, incidence of pneumococcal disease in the United States has been higher among blacks than among whites. Following recommendation of a new 7-valent pneumococcal conjugate vaccine for children in October 2000, the incidence of invasive pneumococcal disease has declined dramatically, but the impact of vaccination on racial disparities in incidence of pneumococcal disease is unknown. To assess the effect of conjugate vaccine introduction on rates of pneumococcal disease among whites and blacks in the United States. Analysis of data from the Active Bacterial Core Surveillance (ABCs)/Emerging Infections Program Network, an active, population-based surveillance system in 7 states. Patients were 15,923 persons with invasive pneumococcal disease occurring between January 1, 1998, and December 31, 2002. Age- and race-specific pneumococcal disease incidence rates (cases per 100 000 persons), rate ratios, and rate differences. Between 1998 and 2002, annual incidence rates for invasive pneumococcal disease decreased from 19.0 to 12.1 cases per 100 000 among whites and from 54.9 to 26.5 among blacks. Due to these declines, 14,730 fewer cases occurred among whites and 8780 fewer cases occurred among blacks in the United States in 2002, compared with 2 prevaccine years, 1998 and 1999. Before vaccine introduction, incidence among blacks was 2.9 times higher than among whites (95% confidence interval [CI], 2.7-3.0); in 2002, the black-white rate ratio had been reduced to 2.2 (95% CI, 2.0-2.4). Incidence among black children younger than 2 years went from being 3.3 times higher (95% CI, 3.0-3.7) than among white children in the prevaccine period to 1.6 times higher (95% CI, 1.1-2.2) in 2002. By 2002, 74% of white children and 68% of black children aged 19 to 35 months in the 7 states had received at least 1 dose of pneumococcal conjugate vaccine; 43% of white and 39% of black children received 3 or more doses. Although blacks remain at higher risk of invasive pneumococcal disease, introduction of childhood pneumococcal vaccination has reduced the racial disparity in incidence of pneumococcal disease.

Enfermedad invasiva por Streptococcus pneumoniae y Haemophilus influenzae serotipo b. Estudio retrospectivo de 12 años

Streptococcus pneumoniae and Haemophilus influenzae serotype b (Hib) are two of the most common causes of invasive bacterial disease in children. The introduction of a successful Hib vaccine and the emergence of penicillin-resistant pneumococci have changed the epidemiology of these bacteria over the last few years. To evaluate the incidence of S. pneumoniae and Hib invasive disease in children (0-15 years) admitted to our hospital during a 12-year period (January 1991-December 2002). We retrospectively reviewed the medical records of 101 children with isolation of S. pneumoniae and Hib in blood, cerebrospinal fluid (CSF) or synovial fluid samples during the study period. SP was isolated in 81 samples (72 in blood and nine in CSF) from 73 children (72.6 % were aged < 2 years). The annual incidence per 100,000 children aged 0-2 years was 53.76 cases (95 % CI: 40.7-70.9). The most common clinical diagnosis was bacteremia (67 %). The percentage of penicillin-resistant strains was 44 %. Hib was isolated in 38 samples (26 in blood, 10 in CSF and two in synovial fluid) from 28 children (82.1 % were aged < 2 years). The most common clinical diagnosis was meningitis (35.7 %). The annual incidence per 100,000 children aged between 0-5 years dropped from 21.52 cases (95 % CI: 14.4-32) to 1.7 cases (95 % CI: 0.1-10.8) after systematic vaccination. The percentage of ampicillin-resistant strains was 63.1 %. The incidence of invasive pneumococcal disease and the increased antimicrobial resistance rates of pneumococcus are two major reasons to support the routine use of pneumococcal conjugate vaccination in children. Systematic Hib vaccination since October 1998 has dramatically reduced the incidence of this disease.

Rousing Success for Pneumococcal Conjugate Vaccine in Children

A 7-valent pneumococcal conjugate vaccine (PCV7; Prevnar) that protects against invasive infection by the seven most common serotypes of Streptococcus pneumoniae was licensed in February 2000. Confirmation of the vaccine's benefits now has been published. In a comparison of 2001 data with data from 1994-2000 (gathered from eight U.S. children's hospitals), researchers reported an overall yearly 58% reduction in invasive pneumococcal infections (IPI) such as meningitis, pneumonia, and bacteremia among children younger than …

Possibility of application of new pneumococcal conjugate vaccines in children in Slovenia

The emergence of pneumococcal strains resistant to penicillin caused a lot of problems in the therapy of invasive diseases, and added new dimensions to the role of immunisation. In addition to the currently available 23-valent pneumococcal polysaccharide vaccine (PPV) and a new 7-valent conjugate vaccine (PCV) (Prevnar, Wyeth Lederle), two new conjugate vaccines—a 9- and a 11-valent—are being developed. So far, the choice of most appropriate vaccines has depended on the established prevalence of serotypes causing invasive diseases and their antibiotic resistance in the Slovene children population. Between 1993 and 2001, 263 invasive pneumococcal strains isolated from children with invasive diseases were typed. During the period 1998–2001, the same 161 invasive strains were tested for their antibiotic sensitivity. Streptococcus pneumoniae was identified as the major cause of invasive bacterial diseases in the Slovene children population, especially in children under 4 years of age. Distribution by age groups showed the highest incidence in children aged 0–1 years. The predominant serotypes in all age groups were serotypes 14, 1, 19F, 23F, 6B, 18C and 6A. The distribution of penicillin-intermediate and penicillin-resistant strains showed the predominance of serotypes 23F, 14 and 19F. As concerns infection with S. pneumoniae serotypes, we have proved that children aged less than 5 years are more likely to be infected with penicillin-nonsusceptible or intermediate susceptible strains than older children. The 7-valent conjugate vaccine covers 74% of invasive strains in toddlers, but is less effective in older children. We can conclude that the 9-valent vaccine formulation is optimal for our country, but further cost-effectiveness analysis must be done for recommendation of wide use. At that moment it is reasonable to use the 7-valent conjugate vaccine for children with chronic cardiovascular, pulmonary, urinary and liver diseases, with asplenia, neoplasmia, diabetes, meningomyelocoele, before or after bone marrow transplantation and in cases of immunodeficiency.

Molecular epidemiology of pneumococcal carriage among children with upper respiratory tract infections in Hanoi, Vietnam.

To investigate the molecular epidemiology of pneumococcal nasopharyngeal carriage in Hanoi, Vietnam, we studied 84 pneumococcal strains retrieved from children with upper respiratory tract infections. Serotypes 23F (32%), 19F (21%), 6B (13%), and 14 (10%) were found most often. A significant number of strains were antibiotic resistant. Fifty-two percent of the strains were (intermediate) resistant to penicillin, 87% were (intermediate) resistant to co-trimoxazole, 76% were resistant to tetracycline, 73% were resistant to erythromycin, and 39% were (intermediate) resistant to cefotaxime. Seventy-five percent were resistant to three or more classes of antibiotics. A high degree of genetic heterogeneity among the penicillin resistance genes was observed. In addition, the tetracycline resistance gene tet(M) and the erythromycin resistance gene erm(B) were predominantly observed among the isolates. Molecular analysis of the 84 isolates by restriction fragment end labeling (RFEL) revealed 35 distinct genotypes. Twelve of these genotypes represented a total of eight genetic clusters with 61 isolates (73%). The two largest clusters contained 24 and 12 isolates, and the isolates in those clusters were identical to the two internationally spreading multidrug-resistant clones Spain 23F-1 and Taiwan 19F-14, respectively. The remaining RFEL types were Vietnam specific, as they did not match the types in our reference collection of 193 distinct RFEL types from 16 countries. Furthermore, 57 of the 61 horizontally spreading isolates (93%) in the eight genetic clusters were covered by the seven-valent conjugate vaccine, whereas this vaccine covered only 43% of the isolates with unique genotypes. According to the serotype distribution of the nasopharyngeal pneumococcal isolates, this study suggests a high potential benefit of the seven-valent pneumococcal conjugate vaccine for children in Hanoi.

Comparative Cost Effectiveness of Varicella, Hepatitis A, and Pneumococcal Conjugate Vaccines

Background. Several state and local U.S. governments are considering making varicella, hepatitis A, and/or pneumococcal conjugate vaccination conditions of day care or school entry. These requirements will likely be issued sequentially, because simultaneous mandates exacerbate budget constraints and complicate communication with parents and providers. Cost-effectiveness assessments should aid the establishment of vaccination priorities, but comparing results of published studies is confounded by their dissimilar methods.Methods. We reviewed U.S. cost-effectiveness studies of childhood varicella, hepatitis A, and pneumococcal conjugate vaccines and identified four providing data required to standardize methods. Vaccination, disease treatment, and work-loss costs were estimated from original study results and current prices. Estimated life-years saved were derived from original study results, epidemiological evidence, and alternative procedures for discounting to present values.Results. Hepatitis A vaccine would have the lowest health system costs per life-year saved. Varicella vaccine would provide the greatest reduction in societal costs, mainly through reduced parent work loss. Pneumococcal conjugate vaccine would cost twice the amount of varicella and hepatitis A vaccines combined and be less cost effective than the other vaccines.Conclusions. Hepatitis A and varicella vaccines, but not pneumococcal conjugate vaccine, meet or exceed conventional standards of cost effectiveness.

Changes in serotype distribution may hamper efficacy of pneumococcal conjugate vaccines in children.

During the last 10 y we have observed an increased incidence of pneumococcal bacteremia in Sweden. In order to study the serotype distribution over time we collected 1136 invasive pneumococcal isolates from 1987, 1992 and 1997 from Swedish microbiological laboratories. Currently, new pneumococcal conjugate vaccines are being considered for introduction in the general childhood vaccination program in several countries, including Sweden. We studied the potential vaccine coverage rate for the new conjugate vaccines among our Swedish invasive isolates. We found that the serotype distribution fluctuated with time and observed a surprisingly low potential coverage rate for the 7-valent vaccine in Sweden, in contrast to other countries. Therefore we argue that pneumococcal conjugate vaccines have to be tailored to suit current, local serotype patterns and most likely will need to be changed over time.

Quality of life in children with acute otitis media (OMAVAX)

Introduction. The objective was to measure the influence of recurrent acute otitis media (AOM) on the quality of life (QoL) in children. This study is part of the OMAVAX trial into the efficacy of vaccination with pneumococcal conjugate vaccine in children with recurrent AOM. Methods. QoL was measured in 306 children, aged 1–6 years, with validated questionnaires, RAND (general health), FS II R (FS-g = functional status in general, FS-s = illness-specific functional status), OM-6 (ear related QoL) and a self-developed questionnaire to measure family burden. Results. Children with four or more AOM episodes a year, so-called otitis-prone children, scored significantly worse than children with two or three AOM episodes a year on the RAND (P = 0.005), FS II R (FS-g P = 0.007; FS-s P = 0.003) and the OM-6 (P = 0.001). The parents of otitis-prone children do not experience a heavier family burden than parents of children with two or three AOM episodes (P = 0.1). Conclusion. Recurrent AOM has a negative influence on the QoL in children and symptoms increase with the number of AOM episodes. Prevention of AOM, for example by vaccination with a pneumococcal vaccine, would be valuable.

Changes in Serotype Distribution may Hamper Efficacy of Pneumococcal Conjugate Vaccines in Children

During the last 10 y we have observed an increased incidence of pneumococcal bacteremia in Sweden. In order to study the serotype distribution over time we collected 1136 invasive pneumococcal isolates from 1987, 1992 and 1997 from Swedish microbiological laboratories. Currently, new pneumococcal conjugate vaccines are being considered for introduction in the general childhood vaccination program in several countries, including Sweden. We studied the potential vaccine coverage rate for the new conjugate vaccines among our Swedish invasive isolates. We found that the serotype distribution fluctuated with time and observed a surprisingly low potential coverage rate for the 7-valent vaccine in Sweden, in contrast to other countries. Therefore we argue that pneumococcal conjugate vaccines have to be tailored to suit current, local serotype patterns and most likely will need to be changed over time.