The distribution and annual changes in the Streptococcus pneumoniae serotypes in adult Japanese patients with pneumococcal pneumonia from 2011 to 2015

Clinical characteristics and antimicrobial susceptibility of non-vaccine serotype Streptococcus pneumoniae in adult Japanese patients with pneumonia

BACKGROUND

Non-vaccine serotype (NVT) pneumococcal pneumonia in Japan has increased with the spread of pneumococcal vaccinations. However, there is no data regarding the clinical background and antimicrobial susceptibility of NVT isolates compared with those of vaccine serotype (VT) isolates in adult pneumococcal pneumonia.

METHODS

The serotypes and antimicrobial susceptibilities of pneumococcal isolates obtained from patients with pneumonia at the University of Occupational and Environmental Health, Japan, from January 2011 to December 2020 were retrospectively evaluated along with the patients' clinical information.

RESULTS

In total, 252 patients with pneumococcal pneumonia (98 NVT and 154 VT isolates) were included. Among NVTs, the most common serotype was 35B, followed by 15A, 34, 6C, 23A, and 15C. The MIC50 and MIC90 of each antibiotic in 35B and 15A tend to be higher than those in 34, 6C, and 23A. Regarding background characteristics, the percentages of patients with dementia and liver disease were significantly higher in patients in the VT group than in those in the NVT group (p = 0.048 and p = 0.012, respectively). There were no significant differences in the severity of pneumonia and mortality rate between patients with the VT and NVT isolates. This study first demonstrated that NVT isolates included those with reduced susceptibility to antibiotics in adult pneumonia in Japan. The data of the present study can be useful in optimizing treatment strategies for pneumococcal pneumonia because of the increasing number of NVT cases in Japan.

Effect of the 23-valent pneumococcal polysaccharide vaccine on the incidence of hospitalisation with pneumonia in adults aged ≥65 years: retrospective cohort study using a population-based database in Japan

OBJECTIVES

The effectiveness of the 23-valent pneumococcal polysaccharide vaccine (PPV23) in preventing pneumonia in older adults remains controversial. Some studies have suggested differences in the effectiveness according to age or sex.

METHODS

We conducted an observational study using the database of vaccine subsidisation data and health insurance claims data for a city in Japan. Participants were residents from 2014 to 2018 turning 65, 70, 75, 80, 85, 90 or 95 years during a given fiscal year, and PPV23 during the first year of observation were identified. We matched vaccinated and non-vaccinated individuals of the same age using propensity scores for vaccination. Incidence of hospitalisation with pneumonia was compared using Fine-Gray regression model. We summarised the results for each age using random-effects meta-analysis and conducted a subgroup analysis by sex.

RESULTS

A total of 102,136 participants were included, of whom 35% received PPV23. Propensity score matching selected 32,510 pairs of vaccinated and non-vaccinated individuals. Overall, PPV23 administration was associated with a decreased incidence of hospitalisation with pneumonia (17.2 vs. 20.4 per 1,000 person-years, sub-distribution hazard ratio: 0.84, 95% confidence interval: 0.77 to 0.91). Vaccine effectiveness was highest among those aged 70 years and decreased with increasing age. No statistically significant effect was observed in those aged 90 or 95 years. Vaccine effectiveness was observed in both males and females.

CONCLUSIONS

PPV23 was associated with an overall decrease in hospitalisation with pneumonia in older adults. However, vaccine effectiveness was significant in those aged 65 to 85 years but not in older population.

Long-term impact of pneumococcal conjugate vaccines for children on adult pneumococcal pneumonia in Japan: Two multicenter observational studies from 2011 to 2020

BACKGROUND

Pediatric pneumococcal conjugate vaccines (PCVs) introduction has directly and indirectly reduced pneumococcal pneumonia and invasive disease caused by PCV-covered serotypes among children and adults globally. In Japan, both PCV7 and PCV13 were introduced into the national immunization program (NIP) for children in 2013. However, the long-term impact of PCV use in children on adult pneumococcal pneumonia in Japan remains unclear.

METHODS

We assessed serotypes isolated from adult pneumococcal pneumonia patients (in- and outpatients) in two multicenter observational studies in Japan: 2011-2014 and 2016-2020. The latter study period was divided into two periods to evaluate changes after PCV introduction in children. The Quellung reaction was used to determine serotypes. We evaluated trends of individual and vaccine-covered serotypes over three periods and assessed the difference in changes by patient group before and after the introduction of pediatric PCVs.

RESULTS

A total of 650 patients were enrolled: 224, 322, and 104 in 2011-2014, 2016-2017, and 2018-2020, respectively. The median age was 73 years; 59.7% (388/650) were male; 86.9% (565/650) had comorbidities; and 10.2% (66/650) were nursing-home residents. The proportion of PCV13 serotypes decreased from 52.7% in 2011-2014 to 30.4% in 2016-2017 (p <0.001) after PCV13 introduction for children. However, PCV13, PCV15, and PCV20 serotypes still accounted for 38.5, 43.3, and 59.6% of total pneumococcal pneumonia in 2018-2020, respectively. Decline of PCV13 serotypes was more marked in patients aged ≥65 (-23.5%; p <0.001) than those aged <65 (-12.3%; p = 0.104) from 2011-2014 to 2016-2020. The proportion of PPSV23 non-PCV13 serotypes didn't change over time.

CONCLUSIONS

The proportion of adult pneumococcal pneumonia caused by PCV13 serotypes in Japan declined after pediatric PCVs introduction into NIP, possibly due to indirect effects of pediatric PCVs. However, use of new PCVs in Japanese adults may potentially prevent additional pneumococcal pneumonia cases. Now, pneumococcal vaccination strategy for older adults requires discussion.

Burden of illness associated with pneumococcal infections in Japan - a targeted literature review

INTRODUCTION

Pneumococcal diseases (PDs) are among the leading causes of mortality and morbidity worldwide. However, the evidence on epidemiology, health economic, and patient-reported outcomes has not been systematically reviewed and published in Japan. This study aimed to assess the burden, treatment adherence and compliance, and serotype distribution associated with PDs in Japan.

METHOD

One hundred and eight studies were identified between January 2005 and June 2020. The identified studies were mostly regional and with a limited scale, clinical settings, and populations.

RESULTS

In 2013-2017, invasive PD incidence rates were 4.98-9.47/100,000 in <4-year-olds, 0.36/100,000 in 5-14-year-olds, 0.46/100,000 in 15-64-year-olds, and 1.50-5.38/100,000 in the elderly. The incidence of invasive PDs in children decreased from 24.6/100,000 in 2008 to 10.7/100,000 in 2013 after the introduction of PCV7 and further declined to 10.3/100,000 in 2014 after PCV13 was introduced. From 2014, the prevalence of PCV13 serotypes decreased across all age groups along with a decrease of PPV23 serotypes, but an increase of PPV23 serotypes not included in PCV13 among adults and the elderly. No study reported health-related quality-of-life data for PDs. In children, direct costs were 340,905-405,978 JPY (3,099-3,691 USD) per pneumococcal bacteraemia, 767,447-848,255 JPY (6,977-7,711 USD) per pneumococcal meningitis, and 79,000 JPY (718 USD) per pneumococcal acute otitis media episodes. In adults and the elderly, the direct cost of pneumococcal pneumonia was 348,280-389,630 JPY (3,166-3,542 USD). The average hospital stay length was 7.2-31.9 days in children, 9.0 days in adults and 9.0-28.7 days in adults and the elderly.

CONCLUSIONS

The epidemiological burden of PDs remains high in Japan, especially among children and the elderly with invasive PDs accounting for a very small proportion of all PDs. A significant impact of the PCV13 vaccine program was reported, while the PPV23's impact remains unclear. A substantial decrease in quality-adjusted life years in adults and the elderly and a high economic burden may exist.

Epidemiology of non-vaccine serotypes of Streptococcus pneumoniae before and after universal administration of pneumococcal conjugate vaccines

The universal administration of pneumococcal conjugate vaccines (PCVs) had been demonstrated as an effective way to prevent Streptococcus pneumoniae infection. However, the immunity induced by PCVs protected against the infections caused by vaccine serotypes, which were usually more frequent than non-vaccine serotypes (NVTs). The prevalence and pathogenicity of NVTs after universal vaccination have caused widespread concern. We reviewed the epidemiology of non-PCV13 S. pneumoniae before and after PCV13 introduction, and explored the potential reasons for the spread of NVTs. Emerging and spreading NVTs can be regarded as the focus for future serotype epidemiological survey and vaccine optimization.AbbreviationsIPD: invasive pneumococcal disease PCV: pneumococcal conjugate vaccines VT: vaccine serotypeNVT: non-vaccine serotype.

A phase 3, multicenter, single-arm, open-label study to assess the safety, tolerability, and immunogenicity of a single dose of 13-valent pneumococcal conjugate vaccine in Japanese participants aged 6-64 years who are considered to be at increased risk of pneumococcal disease and who are naive to pneumococcal vaccines

BACKGROUND

This open-label, single-arm, phase 3 study evaluated safety and immunogenicity of the 13-valent pneumococcal conjugate vaccine (PCV13) in pneumococcal vaccine-naive Japanese individuals aged 6-64 years at increased risk of pneumococcal disease (PD).

METHODS

Participants received 1 PCV13 dose. Reactogenicity events were recorded for 7 days (individuals aged 6- to 17-year-old) or 14 days (individuals aged 18 to 64 years old) postvaccination. Adverse events (AEs) were collected for 1 month postvaccination. Opsonophagocytic activity (OPA) and anticapsular immunoglobulin G (IgG) geometric mean concentrations (GMCs) were measured for vaccine serotypes before and 1 month postvaccination. Post hoc analyses compared immunogenicity in participants categorized as at-risk (immunocompetent but having chronic medical conditions associated with increased PD risk) or high-risk (immunocompromised due to diseases/conditions and/or medications).

RESULTS

206 participants aged 6- to 17-year-old (n = 53) and 18 to 64 years old (n = 153) completed the study. Reactogenicity events were generally mild to moderate in severity. AEs were reported in 16% (33/206) of participants; 1.0% (2/206) were severe. Six AEs were vaccine-related; most were associated with local reactions. No serious AEs occurred. Circulating antibody levels for all 13 serotypes increased postvaccination. OPA geometric mean fold rises (GMFRs) from prevaccination to 1 month postvaccination were 5.5-61.7; lower limits of the 2-sided, 95% CI were > 1 for all serotypes. IgG GMFRs were consistent with OPA analyses. In post hoc analyses, 55.8% (115/206) and 44.2% (91/206) of participants were categorized as at risk and at high risk of PD, respectively; OPA GMFRs from prevaccination to 1 month postvaccination were 3.9-635.1, with lower limits of the 2-sided 95% CIs > 1 for all 13 serotypes across these risk groups; IgG GMFRs were consistent with OPA analyses.

CONCLUSIONS

PCV13 was well tolerated and immunogenic in Japanese individuals aged 6-64 years considered at increased risk of PD. Results were broadly comparable with past PCV13 studies in other Japanese and non-Japanese populations. Registration number: NCT03571607; JapicCTI-184024.

Situational assessment of adult vaccine preventable disease and the potential for immunization advocacy and policy in low- and middle-income countries

By 2050, the number of adults over 65 years of age will be double the under-5 population, and heavily concentrated in low- and middle-income countries. Population growth and increasing life expectancies call for effective healthy aging strategies inclusive of immunization to reduce the burden of vaccine-preventable diseases, improve quality of life, and mitigate antimicrobial resistance. Based on a review of available literature on the pneumococcal disease, influenza, and herpes zoster epidemiology and economic burden, and the health systems and policy barriers for adult immunization, we identified evidence gaps and considerations for prioritizing adult immunization. The body of evidence for adult immunization and the health and economic burden of adult disease is heavily concentrated in high-income countries. The few countries reporting adult immunization policies generally focus on high-risk groups. Despite robust child immunization programs in most countries, adult immunization programs and policies lag far behind and there is a general lack of appropriate delivery platforms. Global adult disease burden and economic costs are substantial but evidence from low- and middle-income countries is limited. There is a need for a strengthened evidence base and political commitment to drive a comprehensive, global technical consensus on adult immunization.

Current situation and need for prevention of invasive pneumococcal disease and pneumococcal pneumonia in 6- to 64-year-olds in Japan

We conducted a systematic review of the literature to evaluate the reported epidemiology and burden of invasive pneumococcal disease (IPD) and pneumococcal pneumonia (PP) among children and adults aged 6-64 years in Japan. Studies published from Japan between September 2009 and September 2019 and indexed in the MEDLINE/PubMed or ICHUSHI databases were evaluated. A majority of the studies reported overlapping age ranges, including children aged <6 years and adults aged >64 years. According to the national surveillance data, 19% of the IPD cases were patients aged 5-59 years, and an increasing trend in IPD cases was reported from 2013 to 2017. Comorbidities were consistent with those reported by the Advisory Committee on Immunization Practices. Deaths from IPD appeared to increase nearly 3-fold between 2013 and 2017. Overall, both 13-valent pneumococcal conjugate vaccine (PCV13) and 23-valent pneumococcal polysaccharide vaccine (PPSV23) coverage was higher for IPD compared with PP. All the serotypes known to be prominent in Japan were also identified as common serotypes (3, 6A, 19A: PCV13 serotypes; 12F: outbreak serotype; 15A, 35B: drug-resistant serotypes). This systematic literature review suggests a substantial burden of IPD and PP in Japanese children and adults aged 6-64 years. The burden of comorbidities, hospitalizations, and mortality was particularly high among adults. Concerted pneumococcal vaccination strategies may help to reduce the incidence and burden of IPD and PP in this large proportion of the Japanese population.

Capturing the trends in hospital standardized mortality ratios for pneumonia: a retrospective observational study in Japan (2010 to 2018)

Background

Pneumonia has a high human toll and a substantial economic burden in developed countries like Japan, where the crude mortality rate was 77.7 per 100,000 people in 2017. As this trend is going to continue with increasing number of the elderly multi-morbid population in Japan; monitoring performance over time is a social need to alleviate the disease burden. The study objective was to determine the characteristics of hospital standardized mortality ratios (HSMRs) for pneumonia in Japan from 2010 to 2018 to describe this trend.

Methods

Data of the DPC (Diagnostic Procedures Combination) database were used, which is an administrative claims and discharge summary database for acute care in-patients in Japan. HSMRs were calculated using the actual and expected numbers of in-hospital deaths, the latter of which was calculated using logistic regression model, with a number of explanatory variables, e.g., age, sex, urgency of admission, mode of transportation, patient volume per month in each hospital, A-DROP score, and Charlson comorbidity index (CCI). We constructed two HSMR models: a single-year model, which included hospitals with > 10 in-patients per month and, a 9-year model, which included those hospitals with complete 9-year data. Predictive accuracy of the logistic models was assessed using c-index (area under receiver operating curve).

Results

Total 230,372 patients were included for the analysis over the 9-year study period. Calculated HSMRs showed wide variation among hospitals. The proportion of hospitals with HSMR less than 100 increased from 36.4% in 2010 to 60.6% in 2018. Both models showed good predictive ability with a c-statistic of 0.762 for the 9-year model, and no less than 0.717 for the single-year model.

Conclusion

This study denoted that HSMRs of pneumonia can be calculated using DPC data in Japan and revealed significant variations among hospitals with comparable case-mixes. Therefore, HSMR can be used as yet another measure to help improve quality of care over time if other indicators are examined in parallel and to get a clear picture of where hospitals excel and lack.

Serotype Distribution, Antimicrobial Susceptibility, and Multilocus Sequencing Type (MLST) of Streptococcus pneumoniae From Adults of Three Hospitals in Shanghai, China

Background:Streptococcus pneumoniae, a main causative agent associated with invasive and non-invasive infection in elderly population, is a major global health problem. After pneumococcal conjugate vaccines (PCV) and pneumococcal polysaccharide vaccines (PPV) were introduced, the distribution of S. pneumoniae serotypes has changed. There was currently limited data on epidemiology and status of antimicrobial resistance of S. pneumoniae in Shanghai.

Objective: To determine the serotype distribution, antimicrobial susceptibility and molecular epidemiology of S. pneumoniae isolated from adults in Shanghai.

Method: A total of 75 S. pneumoniae isolates consecutively collected from 2015 through 2017 were serotyped by conventional multiplex-PCR. The antimicrobial susceptibility was determined by broth microdilution method. The multilocus sequence type (MLST) was performed to estimate the molecular epidemiology.

Results: The predominant serotypes among the isolates were 19F (20.00%), 3 (16.00%), 23F (9.33%), 14 (8.00%), and19A (5.33%). The prevalence of pneumococcal strains with serotypes targeted by vaccines PCV7, PCV10, PCV13, and PPV23 was 44, 45.33, 66.67, and 80%, respectively. Penicillin non-susceptible S. pneumoniae (PNSSP) accounted for 16% of the isolates examined and resistance to erythromycin, azithromycin, tetracycline, clindamycin, cefaclor and trimethoprim-sulfamethoxazole were found in 92.00, 90.67, 86.67, 81.33, 54.67, and 54.67% of isolates, with most isolates (78.67%) presenting multidrug-resistance. The top three sequence types (STs) were ST271 (17.33%), ST180 (9.33%), and ST81 (8.00%). The international resistance clone complexes Spain^23F-1 (n = 4), Netherland³-31 (n = 8), and Taiwan^19F-14 (n = 14) were identified.

Conclusions: The S. pneumoniae isolates showed high genetic diversity in Shanghai and the prevalence of antimicrobial resistance was also high among S. pneumoniae isolates, most of which were multidrug-resistant. The spread of international resistance clones might contribute to the increase of resistant isolates. The PPV23 could protect against most pneumococcal capsular serotypes causing infection of adults in Shanghai.

Distribution and annual changes in the proportion of Streptococcus pneumoniae serotypes in Japanese adults with pneumococcal pneumonia from 2011 to 2017

In 2014, vaccinations with 23-valent pneumococcal polysaccharide vaccine (PPSV23) and 13-valent pneumococcal conjugate vaccine (PCV13) were implemented in Japan for all adults aged ≥65 years. We previously clarified reductions in the proportions of PCV7-, PCV13-, and PPSV23-covered serotypes in patients with pneumococcal pneumonia after the initiation of PCV7 and PCV13 vaccinations for Japanese children; however, information about the annual changes in the proportion of Streptococcus pneumoniae serotypes in patients with pneumococcal pneumonia after the initiation of routine PPSV23 vaccinations remains unclear. We retrospectively studied 229 adults with pneumococcal pneumonia which S. pneumoniae was cultured from their lower respiratory tract samples between 2011 and 2017 and investigated the annual changes in the proportion of S. pneumoniae serotypes. The proportion of PPSV23-covered serotypes decreased from 71.4% in 2011 to 52.2% in 2014, but it remained essentially unchanged from 2015 to 2017. The proportions of PCV7-covered serotypes decreased from 46.4% in 2011 to 4.3% in 2014; however, this rate increased beginning in 2015 and reached 20.6% in 2017. Among the PCV7-covered serotypes, the proportion of the 19F serotype increased from 2015 to 2017. In conclusion, there were no obvious changes in the proportion of PPSV23-covered and PCV13-covered serotypes in patients with pneumococcal pneumonia after the initiation of routine PPSV23 vaccinations.

Impact of the pediatric 13-valent pneumococcal conjugate vaccine on serotype distribution and clinical characteristics of pneumococcal pneumonia in adults: The Japan Pneumococcal Vaccine Effectiveness Study (J-PAVE)

BACKGROUND

The pediatric 13-valent pneumococcal conjugate vaccine (PCV13) was included in the pediatric immunization programme in Japan in late 2013. The impact of vaccination on the serotype distribution and clinical characteristics of pneumococcal pneumonia has not been described.

METHODS

The first phase of this multicentre prospective study was conducted at community-based hospitals in Japan from 2011 to 2014. The second phase was conducted from 2016 to 2017. Pneumococcal isolates and clinical data were collected from patients with community-acquired pneumonia who were ≥15 years of age. Patients were classified by pneumococcal serotype to PCV13 serotype, 23-valent pneumococcal polysaccharide vaccine (PPV23) non-PCV13 serotype, and non-vaccine serotype.

RESULTS

A total of 484 patients were enrolled, 241 in the first phase and 243 in the second. The proportion of PCV13 serotypes decreased from 53% to 33% (p < 0.001), whereas PPV23 non-PCV13 serotypes did not change (p = 0.754). PCV13 serotypes were associated with increased risk of elevated blood urea nitrogen (adjusted odds ratio 2.49; 95% confidence interval: 1.49-4.16) and hospitalization (adjusted odds ratio 1.74; 95% confidence interval: 1.02-2.95). These associations were not observed in patients with PPV23 non-PCV13 serotypes.

CONCLUSIONS

The occurrence of pneumococcal pneumonia caused by vaccine-covered serotypes dramatically decreased following the introduction of pediatric PCV13. The PCV13 serotypes were associated with pneumonia severity.

Broad protective immune responses elicited by bacterium-like particle-based intranasal pneumococcal particle vaccine displaying PspA2 and PspA4 fragments

Streptococcus pneumoniae is an infectious pathogen mainly infecting host bodies through the respiratory system. An effective pneumococcal vaccine would be targeted to the mucosa and provide not only protection against invasive infection but also against colonization in the respiratory system. In the present work, we applied bacterium-like particles (BLPs) as an adjuvant for the development of a PspA mucosal vaccine, in which the PspA protein was displayed on the surface of BLPs. Intranasal immunization with the PspA-BLP pneumococcal vaccine, comprised of PspA2 from pneumococcal family 1 and PspA4 from pneumococcal family 2, not only induced a high level of serum IgG antibodies but also a high level of mucosal SIgA antibodies. Analysis of binding of serum antibodies to intact bacteria showed a broad coverage of binding to pneumococcal strains expressing PspA from clade 1 to 5. Immunization with the PspA-BLP vaccine conferred protection against fatal intranasal challenge with both PspA family 1 and family 2 pneumococcal strains regardless of serotype. Therefore, the PspA-BLP pneumococcal vaccine was demonstrated to be a promising strategy for mucosal immunization to enhance both systemic and mucosal immune responses.