Bacterial etiology of acute otitis media in the era prior to universal pneumococcal vaccination in Taiwanese children

Cost-effectiveness evaluation of the 10-valent pneumococcal non-typeable Haemophilus influenzae protein D conjugate vaccine for children in Taiwan

Background

Streptococcus pneumoniae (S. pneumoniae) and non-typeable Haemophilus influenzae (NTHi) are substantial contributors to morbidity and mortality of diseases including invasive pneumococcal diseases (IPDs), pneumonia and acute otitis media (AOM) worldwide. In Taiwan, 10-valent pneumococcal polysaccharide and NTHi protein D conjugate vaccine (PHiD-CV) and 13-valent pneumococcal conjugate vaccine (PCV13) are licensed in children against pneumococcal disease. In addition to S. pneumoniae, clinical trials suggest efficacy of PHiD-CV against NTHi AOM. This study aims at evaluating the cost-effectiveness of a 2 + 1 schedule of PHiD-CV vs. PCV13 2 + 1 in the universal mass vaccination program of infants in Taiwan.

Methods

A published Markov cohort model was adapted to simulate the epidemiological burden of IPD, pneumonia and AOM for a birth cohort in Taiwan over 10 years. The probability of entering a specific health state was based on the incidence rate of the diseases. Only direct medical costs were included, and costs and outcomes were discounted annually. Vaccine efficacy assumptions were based on published data and validated by a panel of independent experts. Clinical, epidemiological, and serotype distribution data were based on locally published data or the National Health Insurance Research Database. Price parity of vaccines was assumed. Published pneumococcal disease-related disutility weights were used due to lack of local data. Incremental cost-effectiveness ratio was calculated and benchmarked against the recommended threshold in Taiwan. Extensive one-way sensitivity analysis, alternative scenarios and probabilistic sensitivity analysis were performed to test the robustness of the results.

Results

PHiD-CV would potentially reduce the number of NTHi-related AOM cases substantially and prevent comparable IPD and pneumonia-related cases and deaths compared to PCV13. Over a 10-year horizon, PHiD-CV is estimated to dominate PCV13, saving 6.7 million New Taiwan Dollars (NTD) and saving 21 quality-adjusted life years. The result was robust over a wide range of sensitivity analyses. The dominance of PHiD-CV was demonstrated in 90.5% of the simulations.

Conclusions

PHiD-CV 2 + 1 would provide comparable prevention of IPD, pneumonia cases and additional reduction of NTHi-AOM cases, and is considered dominant compared with PCV13 2 + 1 in Taiwan.

A systematic review and meta-analysis of antimicrobial resistance in paediatric acute otitis media

OBJECTIVE OF REVIEW

Acute otitis media (AOM) is the largest cause of antimicrobial prescriptions amongst children in developed countries. Excessive and inappropriate prescribing is known to drive antimicrobial resistance, but less is known of antimicrobial resistance in AOM-associated bacteria.

TYPE OF REVIEW & SEARCH STRATEGY

We conducted a systematic review and meta-analysis of bacterial prevalence and antimicrobial resistance in studies of paediatric AOM identified from Ovid Medline, Embase and the Cochrane library.

RESULTS

From 48 unique studies, 15,871 samples were included. Only 0.67 (CI 0.63-0.71) of all ear samples grew a bacterial pathogen. The most common bacterial causes of AOM in children were Streptococcus pneumoniae 0.30 (CI 0.27-0.32), Haemophilus influenza 0.23 (CI 0.20-0.26), and Moraxella catarrhalis 0.05 (CI 0.04-0.06). Resistance patterns varied amongst organisms and antimicrobial agents. The pooled proportion of bacterial culture-positive episodes of AOM that could be effectively treated with amoxicillin was 0.85 (CI 0.76-0.94), erythromycin was 0.64 (0.48-0.78) and amoxicillin-clavulanate was 0.95 (CI 0.85-0.98).

CONCLUSION

We have demonstrated the bacteriology and antimicrobial resistance patterns of AOM. Of samples which grew bacteria, on average approximately 15% of isolates demonstrated resistance to amoxicillin; a typical first-line agent. Greater understanding of local bacteriology and resistance patterns is needed to enable improved antimicrobial stewardship.

Redistribution of Streptococcus pneumoniae Serotypes After Nationwide 13-valent Pneumococcal Conjugate Vaccine Program in Children in Northern Taiwan

BACKGROUND

After the introduction of 13-valent pneumococcal conjugate vaccine (PCV13) against Streptococcus pneumoniae, public health officials in Taiwan monitored a decline in circulating vaccine serotypes and the emergence of nonvaccine serotypes in children with invasive pneumococcal disease. A gradually expanded PCV13 national immunization program was launched in 2013 in Taiwan. Here, we evaluate the changes in the distribution of pneumococcal serotypes and antimicrobial nonsusceptibility in children during the evolution of vaccination policy.

METHODS

S. pneumoniae isolates from children with pneumococcal disease were collected and serotyped from 2010 to 2015 in northern Taiwan. PCVs were administered at the recipients' expense between 2010 and 2012, and then PCV13 was partially reimbursed by the government beginning in 2013. The distribution and diversity of serotypes were analyzed along with their antimicrobial susceptibilities.

RESULTS

Among a total of 498 isolates, the proportion of invasive pneumococcal disease isolates declined (47.1%-10.6%) during the study period, and serotype diversity increased after 2011. Between 2010 and 2012, the dominant serotypes were 19A, 19F, 3, 6B and 14, and serotype 19A rose from 44.1% to 57.5%. Serotypes 19A, 15A, 19F and 15B were more prevalent from 2013 to 2015, and serotype 19A decreased from 42.1% to 4.5%. Serotypes 19F and 15A became the most commonly detected serotypes in 2015. Overall, PCV13 additional serotypes were reduced by 80% (P < 0.0001) but nonvaccine serotypes increased from 8.8% to 51.5% (P < 0.0001).

CONCLUSIONS

The step-by-step PCV13 national immunization program is effective against pneumococcal disease in Taiwanese children, mainly by reducing PCV13 additional serotypes.

Etiology of acute otitis media and serotype distribution of Streptococcus pneumoniae and Haemophilus influenzae in Chilean children <5 years of age

The impact of bacterial conjugate vaccines on acute otitis media (AOM) is affected by several factors including population characteristics, bacterial etiology and vaccine conjugation method, carrier, and coverage. This study estimated the baseline etiology, distribution, and antibiotic susceptibility of bacterial serotypes that causes AOM in children aged <5 years in a public setting in Santiago, Chile.Children aged ≥3 months and <5 years referred to the physician for treatment of AOM episodes (with an onset of symptoms <72 h) were enrolled between September 2009 and September 2010. Middle ear fluid (MEF) was collected by tympanocentesis or by otorrhea for identification and serotyping of bacteria. Antibacterial susceptibility was tested using E-test (etrack: 112671).Of 160 children (mean age 27.10 ± 15.83 months) with AOM episodes, 164 MEF samples (1 episode each from 156 children; 2 episodes each from 4 children) were collected. Nearly 30% of AOM episodes occurred in children aged 12 to 23 months. Streptococcus pneumoniae (41.7% [58/139]) and Haemophilus influenzae (40.3% [56/139]) were predominant among the cultures that showed bacterial growth (85% [139/164]). All Streptococcus pneumoniae positive episodes were serotyped, 19F (21%) and 14 (17%) were the predominant serotypes; all Haemophilus influenzae strains were nontypeable. Streptococcus pneumoniae were resistant to penicillin (5%) and erythromycin (33%); Haemophilus influenzae were resistant to ampicillin (14%) and cefuroxime and cefotaxime (2% each).AOM in Chilean children is predominantly caused by Streptococcus pneumoniae and nontypeable Haemophilus influenzae. Use of a broad spectrum vaccine against these pathogens might aid the reduction of AOM in Chile.

Streptococcus pneumoniae Serotype Distribution and Pneumococcal Conjugate Vaccine Serotype Coverage among Pediatric Patients in East and Southeast Asia, 2000-2014: a Pooled Data Analysis

Pneumococcal infection is one of the leading causes of death worldwide, especially in children of developing and underdeveloped countries. Capsular polysaccharide-based vaccines are available for the prevention of this disease. A 7-valent pneumococcal conjugate vaccine (PCV7) was licensed in 2000 for use in children less than two years of age. Subsequently, to broaden the protection, 10-valent (PCV10) and 13-valent (PCV13) vaccines were licensed in 2009 and 2010, respectively. All of these conjugate vaccines elicit an immune response that only provides protection against the infection of S. pneumoniae serotypes included in the formulation. Profiles of S. pneumoniae serotype distribution and serotype coverage for both PCV7 and PCV13 have been reported in some Asian countries/territories. But the published results cannot provide conclusive information due to the difference in studied population and geographic areas. The goals of this review are to obtain an accurate estimate of serotype coverage for PCV7, PCV10, and PCV13 and examine the change in the S. pneumoniae serotype distribution after PCV7 use among pediatric patients in East and Southeast Asia through the analysis of pooled data that were published in the English literature between 2000 and 2014.

Pneumococcal disease and use of pneumococcal vaccines in Taiwan

The use of pneumococcal vaccine plays an important role for prevention of invasive pneumococcal disease (IPD). However, introducing the pneumococcal vaccine into the national immunization program (NIP) is complex and costly. The strategy of progressively integrating the pneumococcal conjugate vaccine (PCV) into the NIP in Taiwan provides valuable experience for policy makers. The 7-valent PCV (PCV7) was first available in Taiwan in late 2005. PCV7 was first provided free to children with underlying diseases, those in vulnerable socioeconomic status, and those with inadequate health care resources. The catch-up immunization program with the 13-valent PCV was launched in 2013 and the national pneumococcal immunization program was implemented in 2015. Children aged 2-5 years had the highest incidence of IPD among pediatric population in Taiwan. Although the incidence of IPD caused by PCV7 serotypes has declined, the overall incidence of IPD remained high in the context of PCV7 use in the private sector. A surge of IPD caused by serotype 19A occurred, accounting for 53.6% of IPD cases among children aged ≤ 5 years in 2011-2012. After the implementation of the national pneumococcal immunization program, serogroup 15 has become the leading serogroup for IPD in children. Continued surveillance is necessary to monitor the serotype epidemiology in Taiwan.