Dynamic changes in paediatric invasive pneumococcal disease after sequential switches of conjugate vaccine in Belgium: a national retrospective observational study

Antenatal tetanus, diphtheria, and acellular pertussis (Tdap) immunization and risk of serogroup 19 IPD in children: An indirect cohort study

The tetanus-diphtheria-acellular pertussis (Tdap) vaccine has been indicated for pregnant women in Quebec, Canada since 2018. Recent literature suggests maternal Tdap interferes with the pneumococcal vaccine response in children exposed in utero because of maternally transferred anti-diphtheria antibodies, a phenomenon known as blunting. Using an indirect cohort study, we investigated whether maternal Tdap vaccination could alter the protection of PCV vaccines against serotype 19A/F IPD (conjugated to diphtheria toxoid in PCV10). Thirty-seven immunized IPD cases (serotype 19A/F) and 90 immunized IPD controls (non-vaccine serotypes) were analyzed using multivariate logistic regression. Our analyses did not identify antenatal Tdap exposure as a risk factor for IPD in vaccinated children, with and odds ratio close to the null (odds ratio = 0.82, 95%CI = 0.32-2.07). As this study is the first to assess the impact of maternal immunization on pneumococcal disease risk, future investigations involving a larger number of cases should be conducted to confirm or infirm our findings.

Invasive pneumococcal diseases in Chinese children: a multicentre hospital-based active surveillance from 2019 to 2021

This study aimed to provide data for the clinical features of invasive pneumococcal disease (IPD) and the molecular characteristics of Streptococcus pneumoniae isolates from paediatric patients in China. We conducted a multi-centre prospective study for IPD in 19 hospitals across China from January 2019 to December 2021. Data of demographic characteristics, risk factors for IPD, death, and disability was collected and analysed. Serotypes, antibiotic susceptibility, and multi-locus sequence typing (MLST) of pneumococcal isolates were also detected. A total of 478 IPD cases and 355 pneumococcal isolates were enrolled. Among the patients, 260 were male, and the median age was 35 months (interquartile range, 12-46 months). Septicaemia (37.7%), meningitis (32.4%), and pneumonia (27.8%) were common disease types, and 46 (9.6%) patients died from IPD. Thirty-four serotypes were detected, 19F (24.2%), 14 (17.7%), 23F (14.9%), 6B (10.4%) and 19A (9.6%) were common serotypes. Pneumococcal isolates were highly resistant to macrolides (98.3%), tetracycline (94.1%), and trimethoprim/sulfamethoxazole (70.7%). Non-sensitive rates of penicillin were 6.2% and 83.3% in non-meningitis and meningitis isolates. 19F-ST271, 19A-ST320 and 14-ST876 showed high resistance to antibiotics. This multi-centre study reports the clinical features of IPD and demonstrates serotype distribution and antibiotic resistance of pneumococcal isolates in Chinese children. There exists the potential to reduce IPD by improved uptake of pneumococcal vaccination, and continued surveillance is warranted.

Serotype distribution, clinical characteristics, and antimicrobial resistance of pediatric invasive pneumococcal disease in Colombia during PCV10 mass vaccination (2017-2022)

Introduction

Invasive Pneumococcal Disease (IPD) causes significant morbidity and mortality in children under 5 y. Colombia introduced PCV10 vaccination in 2012, and the Neumocolombia network has been monitoring IPD in pediatric patients since 2008.

Materials and methods

This study is a secondary analysis of a prospective cohort involving pediatric patients with IPD admitted to 17 hospitals in Colombia, from January 1st, 2017, to December 31st, 2022. We present data on serotypes (Spn), clinical characteristics, and resistance patterns.

Results

We report 530 patients, 215 (40.5%) were younger than 24 months. Among these, 344 cases (64.7%) presented with pneumonia, 95 (17.9%) with primary bacteremia, 53 (10%) with meningitis, 6 (1.1%) had pneumonia and meningitis, and 32 (6%) had other IPD diagnosis. The median hospital stay was 12 days (RIQ 8-14 days), and 268 (50.6%) were admitted to the ICU, of whom 60 (11.3%) died. Serotyping was performed in 298 (56.1%). The most frequent serotypes were Spn19A (51.3%), Spn6C (7.7%), Spn3 (6.7%), Spn6A (3.6%), and Spn14 (3.6%). Of 495 (93%) isolates with known susceptibility, 46 (9.2%) were meningeal (M) and 449 (90.7%) non-meningeal (NM). Among M isolates, 41.3% showed resistance to penicillin, and 21.7% decreased susceptibility to ceftriaxone. For NM isolates, 28.2% had decreased susceptibility to penicilin, and 24.2% decreased susceptibility to ceftriaxone. Spn19A showed the highest resistant to penicillin at 47% and was linked to multiresistance.

Conclusion

The prevalence of PCV10-included serotypes decreased, while serotypes 19A and 6C increased, with Spn19A being associated with multiresistance. These findings had played a crucial role in the decision made by Colombia to modify its immunization schedule by switching to PCV13 in July 2022.

The impact of pneumococcal serotype replacement on the effectiveness of a national immunization program: a population-based active surveillance cohort study in New Zealand

Background

In Aotearoa New Zealand (NZ) PCV7 was introduced in 2008, then PCV10 in 2011 and PCV13 in 2014. In 2017 PCV10 was re-introduced, replacing PCV13. In the present study, we investigate the resultant rapidly changing invasive pneumococcal disease (IPD) epidemiology.

Methods

We compare the IPD incidence rate ratio (IRR) in NZ (2022 versus 2020) with other countries, and describe the IPD epidemiology (including trends in overall IPD and serotype 19A, and antimicrobial resistance) within NZ. Additionally, we performed a genomic-epidemiology investigation identifying the most common 19A sequence types and associated risk factors.

Findings

Though IPD incidence rates have increased in the US and Australia (2021-22) after declines in 2020, in NZ the incidence rate is the highest since 2011 with a significantly higher IRR than US (p < 0.01). Incidence rates among children <2 and adults 65 or over in 2022 are the highest since 2009, driven by significant increases of serotype 19A (p = 0.01). Māori and Pacific peoples are experiencing the highest rates since 2009. Further, penicillin resistance among 19A isolates has increased from 39% (2012) to 84% (2021) (p = 0.02). Genomic sequencing identified the more virulent ST-2062 as most common among 19A isolates sequenced, increasing from 5% (2010) to 55% (2022).

Interpretation

With very high incidence rates of IPD in NZ, inadequate protection against 19A, increasing resistance, and a more virulent 19A clade, targeted public health campaigns and increased PCV13 availability are needed.

Funding

The NZ Ministry of Health funds IPD surveillance and typing in NZ.

The role of real-world evidence for regulatory and public health decision-making for Accelerated Vaccine Deployment- a meeting report

The COVID-19 pandemic underscored the need for rapid evidence generation to inform public health decisions beyond the limitations of conventional clinical trials. This report summarises presentations and discussions from a conference on the role of Real-World Evidence (RWE) in expediting vaccine deployment. Attended by regulatory bodies, public health entities, and industry experts, the gathering was a collaborative exchange of experiences and recommendations for leveraging RWE for vaccine deployment. RWE proved instrumental in refining decision-making processes to optimise dosing regimens, enhance guidance on target populations, and steer vaccination strategies against emerging variants. Participants felt that RWE was successfully integrated into lifecycle management, encompassing boosters and safety considerations. However, challenges emerged, prompting a call for improvements in data quality, standardisation, and availability, acknowledging the variability and potential inaccuracies in data across diverse healthcare systems. Regulatory transparency should also be prioritised to foster public trust, and improved collaborations with governments are needed to streamline data collection and navigate data privacy regulations. Moreover, building and sustaining resources, expertise, and infrastructure in LMICs emerged as imperative for RWE-generating capabilities. Continued stakeholder collaboration and securing adequate funding emerged as vital pillars for advancing the use of RWE in shaping responsive and effective public health strategies.

Long-term surveillance of invasive pneumococcal disease: The impact of 10-valent pneumococcal conjugate vaccine in the metropolitan region of Salvador, Brazil

BACKGROUND

In 2010, Brazil introduced the ten-valent pneumococcal conjugate vaccine (PCV10) in the national infant immunization program. Limited data on the long-term impact of PCV10 are available from lower-middle-income settings. We examined invasive pneumococcal disease (IPD) in Salvador, Bahia, over 11 years.

METHODS

Prospective laboratory-based surveillance for IPD was carried out in 9 hospitals in the metropolitan region of Salvador from 2008 to 2018. IPD was defined as Streptococcus pneumoniae cultured from a normally sterile site. Serotype was determined by multiplex polymerase chain reaction and/or Quellung reaction. Incidence rates per 100,000 inhabitants were calculated for overall, vaccine-type, and non-vaccine-type IPD using census data as the denominator. Incidence rate ratios (IRRs) were calculated to compare rates during the early (2010-2012), intermediate (2013-2015), and late (2016-2018) post-PCV10 periods in comparison to the pre-PCV10 period (2008-2009).

RESULTS

Pre-PCV10, overall IPD incidence among all ages was 2.48/100,000. After PCV10 introduction, incidence initially increased (early post-PCV10 IRR 3.80, 95% CI 1.18-1.99) and then declined to 0.38/100,000 late post-PCV10 (IRR 0.15; 95% CI 0.09-0.26). The greatest reductions in the late post-PCV10 period were observed in children aged ≤2 years, with no cases (IRR not calculated) and those ≥60 years (IRR 0.11, 95% CI 0.03-0.48). Late post-PCV10, significant reductions were observed for both PCV10 serotypes (IRR 0.02; 95% CI 0.0-0.15) and non-PCV10 serotypes (IRR 0.27; 95%CI 0.14-0.53). Non-PCV10 serotypes 15B, 12F, 3, 17F, and 19A became predominant late post-PCV10 without a significant increase in serotype-specific IPD incidence compared to pre-PCV10.

CONCLUSION

Significant declines in IPD, including among adults not eligible for vaccination, suggest direct and indirect protection up to nine years after PCV10 introduction, without evidence of significant replacement disease. Continued surveillance is needed to monitor changes in non-vaccine serotypes and inform decisions about introducing higher valent PCVs.

Clonal diversity of Streptococcus pneumoniae serotype 19A collected from children < 5 years old in Québec, Canada, 2016-2021

Streptococcus pneumoniae serotype 19A is a highly diverse, often antimicrobial-resistant Gram-positive bacterium which can cause invasive pneumococcal disease (IPD). In 2021, public health authorities in the Canadian province of Québec observed an increase of serotype 19A IPD in children <5 years. The purpose of this study was to determine the clonal composition of serotype 19A isolates collected from this age group in Québec, from 2016 to 2021. Forty-one and 37 IPD isolates from children <5 years from Québec and the remainder of Canada, respectively, were sequenced using the Illumina NextSeq platform. Phylogenetic analysis using SNVPhyl identified three clusters, corresponding to three common clones of serotype 19A: CC199, CC320 and ST695. CC199, predominantly represented by ST416, accounted for similar proportions of serotype 19A isolates collected from children in Québec (19.5 %) and other Canadian jurisdictions (OCJs, 21.6 %), with significant presence of ermB (62.5 % and 60 % of ST416 isolates, respectively). CC320 was more commonly identified from OCJs in comparison to Québec (18.9 % vs. 7.3 %, respectively), but were highly antimicrobial-resistant regardless of region. ST695 was the most common clone of serotype 19A collected in Québec from children <5 years, representing 65.9 % of isolates collected over the study period (40.5 % of isolates collected in OCJs). Phylogenetic analysis identified geographical differences in ST695 across Canada; including a large clade specific to Québec (with both susceptible and macrolide-resistant [ermB] subclades), and a separate macrolide-resistant (mefA) clade associated with OCJs. The Québec-specific ermB-ST695 clone represented 48.1 % of ST695 collected from the province. Continued genomic surveillance of S. pneumoniae serotype 19A is required to: i) track the prevalence and clonal composition of serotype 19A in Québec in future years; ii) characterize the clonal distribution of serotype 19A in adult populations; and iii) monitor whether the currently geographically restricted ermB-ST695 clone observed in Québec expands to OCJs.

Pediatric outpatient visits and antibiotic use attributable to higher valency pneumococcal conjugate vaccine serotypes

Importance

Streptococcus pneumoniae is a known etiology of acute respiratory infections (ARIs), which account for large proportions of outpatient visits and antibiotic use in children. In 2023, 15- and 20-valent pneumococcal conjugate vaccines (PCV15, PCV20) were recommended for routine use in infants. However, the burden of outpatient healthcare utilization among U.S. children attributable to the additional, non-PCV13 serotypes in PCV15/20 is unknown.

Objective

To estimate the incidence of outpatient visits and antibiotic prescriptions in U.S. children for acute otitis media, pneumonia, and sinusitis associated with PCV15- and PCV20-additional serotypes (non-PCV13 serotypes) to quantify potential impacts of PCV15/20 on outpatient visits and antibiotic prescriptions for these conditions.

Design

Multi-component study including descriptive analyses of cross-sectional and cohort data on outpatient visits and antibiotic prescriptions from 2016-2019 and meta-analyses of pneumococcal serotype distribution in non-invasive respiratory infections.

Setting

Outpatient visits and antibiotic prescriptions among U.S. children.

Participants

Pediatric visits and antibiotic prescriptions among children captured in the National Ambulatory Medical Care Survey (NAMCS), the National Hospital Ambulatory Medicare Care Survey (NHAMCS), and Merative MarketScan, collectively representing healthcare delivery across all outpatient settings. Incidence denominators estimated using census (NAMCS/NHAMCS) and enrollment (MarketScan) data.

Main outcomes and measures

Pediatric outpatient visit and antibiotic prescription incidence for acute otitis media, pneumonia, and sinusitis associated with PCV15/20-additional serotypes.

Results

We estimated that per 1000 children annually, PCV15-additional serotypes accounted for 2.7 (95% confidence interval 1.8-3.9) visits and 2.4 (1.6-3.4) antibiotic prescriptions. PCV20-additional serotypes resulted in 15.0 (11.2-20.4) visits and 13.2 (9.9-18.0) antibiotic prescriptions annually per 1,000 children. Projected to national counts, PCV15/20-additional serotypes account for 173,000 (118,000-252,000) and 968,000 (722,000-1,318,000) antibiotic prescriptions among U.S. children each year, translating to 0.4% (0.2-0.6%) and 2.1% (1.5-3.0%) of all outpatient antibiotic use among children.

Conclusions and relevance

PCV15/20-additional serotypes account for a large burden of pediatric outpatient healthcare utilization. Compared with PCV15-additional serotypes, PCV20-additional serotypes account for >5 times the burden of visits and antibiotic prescriptions. These higher-valency PCVs, especially PCV20, may contribute to preventing ARIs and antibiotic use in children.

Comparison of the epidemiology of invasive pneumococcal disease between Australia and New Zealand in 2017-2021: an observational study based on surveillance data

Background

The Australian immunisation schedule uses 13-valent pneumococcal conjugate vaccine (PCV13), while New Zealand (NZ) changed from PCV13 to 10-valent PCV (PCV10) in 2017. In NZ, cases of serotype 19A (not in PCV10) have been increasing since 2017. We compared invasive pneumococcal disease (IPD) epidemiology between Australia and NZ in 2017-2021.

Methods

We collated IPD notification data from national surveillance systems. Between Australia and NZ, we compared IPD incidence rates and assessed the proportion of serotype 19A, and stratified for ethnicity and age.

Findings

Between 2017 and 2021, the crude IPD incidence per 100,000 in Australia ranged from 4.3 to 8.4, and ranged from 6.9 to 11.4 in NZ. The highest age-adjusted IPD rates were observed in Australian Indigenous people (range: 27.3-35.5) followed by NZ Māori/Pacific peoples (range 19.7-30.4). For children <2 years, ethnicity-adjusted IPD rates were similar between Australia and NZ in 2017-2020. In 2021, however, the ethnicity-adjusted incidence in children <2 years was higher in NZ (30.2; 95% CI 21.1-39.4) than in Australia (23.3 95% CI: 19.5-27.1) (p < 0.01). In Australia, the proportion of serotype 19A remained 5%, whereas in NZ serotype 19A increased from 11.5% to 29.5% with the largest increase in children <2 years and 2-4 years.

Interpretation

Despite higher risks in Indigenous populations in Australia compared to all other groups, the overall IPD rate in NZ is increasing, particularly among children. The numbers and proportions of IPD due to serotype 19A are increasing in NZ especially in children. These data support the NZ decision from December 2022 to change to PCV13.

Funding

This research received no specific funding.

Cost-Effectiveness Analysis of the South African Infant National Immunization Program for the Prevention of Pneumococcal Disease

INTRODUCTION

Pneumococcal disease, which presents a substantial health and economic burden, is prevented through pneumococcal vaccination programs. We assessed the impact of switching from a 13-valent-based (PCV13) to lower 10-valent-based (PCV10-GlaxoSmithKline [GSK] or PCV10-Serum Institute of India [SII]) or higher-valent (PCV15 or PCV20) vaccination programs in South Africa.

METHODS

A previously published decision-analytic model was adapted to a South African setting. Historical invasive pneumococcal disease (IPD) incidence data were used to project IPD incidence over time for each vaccination program on the basis of serotype coverage. Historical incidence (IPD, pneumonia, otitis media), mortality, costs, and utilities were obtained from the published literature. Cases of disease, direct medical costs (i.e., vaccination, IPD, pneumonia, and otitis media costs) (in 2022 South African rands), life-years, quality-adjusted life-years (QALY), and incremental cost per QALY were estimated over a 5- and 10-year horizon for PCV13 and the PCV10 vaccines. Additionally, a public health impact analysis was conducted comparing PCV13, PCV15, and PCV20.

RESULTS

Continuing use of PCV13 would substantially reduce disease incidence over time compared with switching to either of the PCV10 lower-valent vaccines. Cases of IPD were reduced by 4.22% and 34.70% when PCV13 was compared to PCV10-GSK and PCV10-SII, respectively. PCV13 was also found to be cost saving over 5- and 10-year time horizons compared with PCV10-SII and to be cost-effective over a 5-year time horizon and cost-saving over a 10-year time horizon compared with PCV10-GSK. PCV20 was consistently estimated to prevent more cases than the PCV10 vaccines, PCV13, or PCV15.

CONCLUSIONS

Switching from a higher-valent to a lower-valent vaccine may lead to disease incidence re-emergence caused by previously covered serotypes. Maintaining PCV13 was estimated to improve public health further by averting additional pneumococcal disease cases and saving more lives and also to reduce total costs in most scenarios. Higher-valent PCVs can achieve the greatest public health impact in the pediatric vaccination program in South Africa.

Self-Aware SGD: Reliable Incremental Adaptation Framework For Clinical AI Models

Healthcare is dynamic as demographics, diseases, and therapeutics constantly evolve. This dynamic nature induces inevitable distribution shifts in populations targeted by clinical AI models, often rendering them ineffective. Incremental learning provides an effective method of adapting deployed clinical models to accommodate these contemporary distribution shifts. However, since incremental learning involves modifying a deployed or in-use model, it can be considered unreliable as any adverse modification due to maliciously compromised or incorrectly labelled data can make the model unsuitable for the targeted application. This paper introduces self-aware stochastic gradient descent (SGD), an incremental deep learning algorithm that utilises a contextual bandit-like sanity check to only allow reliable modifications to a model. The contextual bandit analyses incremental gradient updates to isolate and filter unreliable gradients. This behaviour allows self-aware SGD to balance incremental training and integrity of a deployed model. Experimental evaluations on the Oxford University Hospital datasets highlight that self-aware SGD can provide reliable incremental updates for overcoming distribution shifts in challenging conditions induced by label noise.

Chronic medical conditions associated with invasive pneumococcal diseases in inpatients in teaching hospitals in São Paulo city: Estimating antimicrobial susceptibility and serotype-coverage of pneumococcal vaccines

BACKGROUND

Chronic conditions increase the risk of invasive pneumococcal diseases (IPD). Pneumococcal vaccination remarkably reduced IPD morbimortality in vulnerable populations. In Brazil, pneumococcal vaccines are included in the National Immunization Program (PNI): PCV10 for < 2 years-old, and PPV23 for high risk-patients aged ≥ 2 years and institutionalized ≥ 60 years. PCV13 is available in private clinics and recommended in the PNI for individuals with certain underlying conditions.

METHODS

A retrospective study was performed using clinical data from all inpatients from five hospitals with IPD from 2016 to 2018 and the corresponding data on serotype and antimicrobial-non-susceptibility of pneumococcus. Vaccine-serotype-coverage was estimated. Patients were classified according to presence of comorbidities: healthy, without comorbidities; at-risk, included immunocompetent persons with specific medical conditions; high-risk, with immunocompromising conditions and others RESULTS: 406 IPD cases were evaluated. Among 324 cases with information on medical conditions, children < 5 years were mostly healthy (55.9%), while presence of comorbidity prevailed in adults ≥ 18 years old (> 82.0%). Presence of ≥1 risk condition was reported in ≥ 34.8% of adults. High-risk conditions were more frequent than at-risk in all age groups. Among high-risk comorbidity (n = 211), cancer (28%), HIV/AIDS (25.7%) and hematological diseases (24.5%) were the most frequent. Among at-risk conditions (n = 89), asthma (16.5%) and diabetes (8.1%) were the most frequent. Among 404 isolates, 42.9% belonged to five serotypes: 19A (14.1%), 3 (8.7%), 6C (7.7%), 4 and 8 (6.2% each); 19A and 6C expressed antimicrobial-non-susceptibility. The vaccine-serotype-coverage was: PCV10, 19.1%, PCV13, 43.8%; PCV15, 47.8%; PCV20, 62.9%; PCV21, 65.8%, and PPV23, 67.3%. Information on hospital outcome was available for 283 patients, of which 28.6% died. Mortality was 54.2% for those with meningitis.

CONCLUSION

Vaccine with expanded valence of serotypes is necessary to offer broad prevention to IPD. The present data contribute to pneumococcal vaccination public health policies for vulnerable patients, mainly those with comorbidity and the elderly.

The 20-valent pneumococcal conjugate vaccine (PCV20): expected added value

OBJECTIVES

Currently existing pneumococcal vaccines have contributed to a major reduction in pneumococcal disease. However, there remains an unmet need for vaccine coverage of serotypes not included in PCV13 to further reduce the burden of disease. The objective of this review is to assess the potential impact of implementation of the investigational 20-valent pneumococcal conjugate vaccine (PCV20) in the childhood and adult immunization programme in Belgium and Europe.

METHODS

A literature search was conducted to identify publications and surveillance reports concerning the effectiveness and safety of pneumococcal vaccines, epidemiological data on pneumococcal disease or serotype distribution dynamics after introduction of systematic vaccination.

RESULTS

Serotypes included in PCV20 currently account for the majority of pneumococcal disease in Belgium and Europe. In Belgium, PCV20-serotypes accounted for 71.4% of invasive pneumococcal disease (IPD) cases across all age groups in 2019, of which 39.2% were caused by PCV20-non-PCV13-serotypes. In Europe, these seven serotypes accounted for 37,6% of IPD cases in 2018.  PCV20 has proven to be well tolerated in vaccine-naïve adults and elicits a substantial immune response against all serotypes included.

CONCLUSION

Due to serotype replacement following the introduction of PCV7 and PCV13, a considerable proportion of pneumococcal disease is currently caused by PCV20-serotypes. PCV20 has the potential of preventing more pneumococcal disease in children and the adult population at risk than the existing conjugate vaccines. The available evidence on safety and immunogenicity of PCV20 is promising, but further research is needed to provide data about vaccine effectiveness, immune response duration and replacement phenomenon after introduction of PCV20.

Streptococcus pneumoniae as cause of acute otitis media (AOM) in Slovak children in the pneumococcal conjugate vaccine era (2008-2019)

AIM

Little data is available on pneumococcal serotypes and their antimicrobial resistance in the pneumococcal conjugate vaccination era in young children with acute otitis media (AOM). Here such data is provided from Slovakia, acountry with sequential introduction and parallel-use of the three commercially available pneumococcal conjugate vaccines (PCVs; PCV7; PCV13; PCV10).

METHODS

This observational study takes advantage of the fact that tympanocentesis is the standard of care in children with AOM in Slovakia. Over the 12 year observation period, participating pediatric ENT specialists sent samples taken during tympanocentesis from children with AOM to their local MEDIRIX laboratories for identification of bacteria. Pneumcoccal isolates were serotyped and tested for antimicrobial resistance. Incidence data could be calculated from 1 region.

RESULTS

Study participation and completeness of typing increased over time. Based on testing of 1,131 isolates over 12 years, PCV7-serotypes rapidly waned after PCV7 introduction in 2009 and had virtually disappeared in 2014. The maximum fraction of PCV10-only isolates (1, 5, 7F) was 2.7 % (2009) whereas the additional 3 PCV-serotypes (3, 6A, 19A) in PCV13 represented the largest proportion of pneumococcal AOM cases as of 2010. This finding remained unchanged during the period of highest PCV10-market share (2012-2017) and even until the end of the observation period (2019). The fraction of untypeable pneumococci (<6 %) and non-PCV13-serotypes (16-34 %) increased 2012-2017, but decreased again thereafter. Serotype 19A evolved as the most relevant (multidrug-) resistant pneumococcal serotype, again particularly during the time with high sales of PCV10 (2012-2017). Incidence data from the Bratislava region document a huge impact of PCV use (77 % vaccine uptake: mainly PCV13) on AOM in children < 6 years. Serotypes 19A and 3 remain the only relevant pneumococcal serotypes in young Slovakian children with AOM.

CONCLUSIONS

As AOM is one of the most common bacterial infections in children < 6 years, the observed benefits of PCVs in reducing vaccine serotypes have been tremendous. With sequential / parallel-use of PCVs, serotypes 3 and (MDR-) 19A today make the largest proportion (about 2/3) of pneumococcal AOM in Slovakia. This data will help to further guide the choice of pneumococcal conjugate vaccines for pediatricians and parents.

Serotype 19A and 6C Account for One-Third of Pneumococcal Carriage Among Belgian Day-Care Children Four Years After a Shift to a Lower-Valent PCV

BACKGROUND

Pneumococcal conjugate vaccines (PCVs) effectively reduce infection and asymptomatic carriage of Streptococcus pneumoniae vaccine serotypes. In 2016, Belgium replaced its infant PCV13 program by a 4-year period of PCV10. Concomitantly, S. pneumoniae serotype carriage was monitored together with the carriage of other nasopharyngeal pathogens in children attending day-care centers.

METHODS

From 2016 to 2019, a total of 3459 nasopharyngeal swabs were obtained from children aged 6-30 months. Culture and qPCR were used for the identification of S. pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, and Staphylococcus aureus and for serotyping and antimicrobial susceptibility assessment of S. pneumoniae strains.

RESULTS

S. pneumoniae colonization was frequent and stable over the study years. H. influenzae and M. catarrhalis were more frequently carried (P < .001) than S. pneumoniae, by, respectively, 92.3% and 91.0% of children. Prevalence of all PCV13 serotypes together increased significantly over time from 5.8% to 19.6% (P < .001) and was attributable to the increasing prevalence of serotype 19A. Coincidently, non-vaccine serotype 6C increased (P < .001) and the overall pneumococcal non-susceptibility to tetracycline and erythromycin. Non-susceptibility to cotrimoxazole decreased (P < .001).

CONCLUSIONS

The switch to a PCV program no longer covering serotypes 19A, 6A, and 3 was associated with a sustained increase of serotypes 19A and 6C in healthy children, similarly as in invasive pneumococcal disease. This resulted in a re-introduction of the 13-valent conjugate vaccine during the summer of 2019.

Recommendations and Health Technology Assessment (HTA) landscape evaluation for pediatric pneumococcal conjugate vaccines (PCV) in Europe: A systematic literature review

National Immunization Technical Advisory Groups (NITAGs) and Health Technology Assessment (HTA) agencies evaluate the value of vaccines and provide decision-making authorities with recommendations. The availability of information on disease-burden evidence considered or required for the assessment of vaccines included in national immunization programs (NIPs) is limited. The aim of this review is to summarize the epidemiologic and health economic (HE) evidence considered by NITAGs/HTA agencies when evaluating pediatric pneumococcal conjugate vaccine (PCV) NIPs. A systematic literature review of national recommendation reports for PCV NIPs in children in 31 European countries, published since 2001, was performed using NITAG/HTA agency websites, Google, MEDLINE, and EMBASE. The presence of epidemiological data was mapped, HE data was extracted, and findings were summarized. A total of 46 records for 19 countries were identified. Fifteen countries' records included a recommendation concerning implementation of PCV NIP, switching from one PCV to another or a change in vaccination schedule within an existing NIP. All of these included epidemiological invasive pneumococcal disease data, and to varying degree epidemiological data on acute otitis media and pneumonia. HE data was referenced in 13 countries' records, with 8 countries providing in-depth details on cost-effectiveness analyses. Pediatric PCV NIP recommendations were published by 61% of European countries, with varying degree of details and decision rationale. Some countries only publish the HE aspect of their rationale. The identified material can provide insight and support local policymakers and clinicians how data influenced the decision-making process in their countries.

Characterization of Emerging Serotype 19A Pneumococcal Strains in Invasive Disease and Carriage, Belgium

After switching from 13-valent to 10-valent pneumococcal conjugate vaccine (PCV10) (2015-2016) for children in Belgium, we observed rapid reemergence of serotype 19A invasive pneumococcal disease (IPD). Whole-genome sequencing of 166 serotype 19A IPD isolates from children (n = 54) and older adults (n = 56) and carriage isolates from healthy children (n = 56) collected after the vaccine switch (2017-2018) showed 24 sequence types (STs). ST416 (global pneumococcal sequence cluster [GPSC] 4) and ST994 (GPSC146) accounted for 75.9% of IPD strains from children and 65.7% of IPD (children and older adults) and carriage isolates in the PCV10 period (2017-2018). These STs differed from predominant 19A IPD STs after introduction of PCV7 (2011) in Belgium (ST193 [GPSC11] and ST276 [GPSC10]), which indicates that prediction of emerging strains cannot be based solely on historical emerging strains. Despite their susceptible antimicrobial drug profiles, these clones spread in carriage and IPD during PCV10 use.

Distribution of Serotypes Causing Invasive Pneumococcal Disease in Children From High-Income Countries and the Impact of Pediatric Pneumococcal Vaccination

BACKGROUND

The introduction and adoption of pneumococcal conjugate vaccines (PCVs) into pediatric national immunization programs (NIPs) has led to large decreases in invasive pneumococcal disease (IPD) incidence caused by vaccine serotypes. Despite these reductions, the global IPD burden in children remains significant.

METHODS

We collected serotype-specific IPD data from surveillance systems or hospital networks of all 30 high-income countries that met inclusion criteria. Data sources included online databases, surveillance system reports, and peer-reviewed literature. Percentage of serotyped cases covered were calculated for all countries combined and by PCV type in the pediatric NIP.

RESULTS

We identified 8012 serotyped IPD cases in children <5 or ≤5 years old. PCV13 serotype IPD caused 37.4% of total IPD cases, including 57.1% and 25.2% for countries with PCV10 or PCV13 in the pediatric NIP, respectively, most commonly due to serotypes 3 and 19A (11.4% and 13.3%, respectively, across all countries). In PCV10 countries, PCV15 and PCV20 would cover an additional 45.1% and 55.6% of IPD beyond serotypes contained in PCV10, largely due to coverage of serotype 19A. In PCV13 countries, PCV15 and PCV20 would cover an additional 10.6% and 38.2% of IPD beyond serotypes contained in PCV13. The most common IPD serotypes covered by higher valency PCVs were 10A (5.2%), 12F (5.1%), and 22F and 33F (3.5% each).

CONCLUSIONS

Much of the remaining IPD burden is due to serotypes included in PCV15 and PCV20. The inclusion of these next generation PCVs into existing pediatric NIPs may further reduce the incidence of childhood IPD.

Effectiveness of 10 and 13-valent pneumococcal conjugate vaccines against invasive pneumococcal disease in European children: SpIDnet observational multicentre study

BACKGROUND

Pneumococcal conjugate vaccines covering 10 (PCV10) and 13 (PCV13) serotypes have been introduced in the infant immunization schedule of most European countries in 2010-11. To provide additional real-life data, we measured the effectiveness of PCV10 and PCV13 against invasive pneumococcal disease (IPD) in children of 12 European sites (SpIDnet).

METHODS

We compared the vaccination status of PCV10 and PCV13 serotype IPD (cases) to that of nonPCV13 serotype IPD (controls) reported in 2012-2018. We calculated pooled effectiveness as (1-vaccination odds ratio)*100, and measured effectiveness over time since booster dose.

RESULTS

The PCV13 and PCV10 studies included 2522 IPD cases from ten sites and 486 cases from four sites, respectively. The effectiveness of ≥ 1 PCV13 dose was 84.2% (95 %CI: 79.0-88.1) against PCV13 serotypes (n = 2353) and decreased from 93.1% (87.8-96.1) < 12 months to 85.1% (72.0-92.1) ≥ 24 months after booster dose. PCV13 effectiveness of ≥ 1 dose was 84.7% (55.7-94.7) against fatal PCV13 IPD, 64.5% (43.7-77.6), 83.2% (73.7-89.3) and 85.1% (67.6-93.1) against top serotypes 3, 19A and 1, respectively, and 85.4% (62.3-94.4) against 6C. Serotype 3 and 19A effectiveness declined more rapidly. PCV10 effectiveness of ≥ 1 dose was 84.8% (69.4-92.5) against PCV10 serotypes (n = 370), 27.2% (-187.6 to 81.6) and 85.3% (35.2-96.7) against top serotypes 1 and 7F, 32.5% (-28.3 to 64.5) and -14.4% (-526.5 to 79.1) against vaccine-related serotypes 19A and 6C, respectively.

CONCLUSIONS

PCV10 and PCV13 provide similar protection against IPD due to the respective vaccine serotype groups but serotype-specific effectiveness varies by serotype and vaccine. PCV13 provided individual protection against serotype 3 and vaccine-related serotype 6C IPD. PCV10 effectiveness was not significant against vaccine-related serotypes 19A and 6C. PCV13 effectiveness declined with time after booster vaccination. This multinational study enabled measuring serotype-specific vaccine effectiveness with a precision rarely possible at the national level. Such large networks are crucial for the post-licensure evaluation of vaccines.

Validation of Fourier Transform Infrared Spectroscopy for Serotyping of Streptococcus pneumoniae

Fourier transform infrared (FT-IR) spectroscopy (IR Biotyper; Bruker) allows highly discriminatory fingerprinting of closely related bacterial strains. In this study, FT-IR spectroscopy-based capsular typing of Streptococcus pneumoniae was validated as a rapid, cost-effective, and medium-throughput alternative to the classical phenotypic techniques. A training set of 233 strains was defined, comprising 34 different serotypes and including all 24 vaccine types (VTs) and 10 non-vaccine types (NVTs). The acquired spectra were used to (i) create a dendrogram where strains clustered together according to their serotypes and (ii) train an artificial neural network (ANN) model to predict unknown pneumococcal serotypes. During validation using 153 additional strains, we reached 98.0% accuracy for determining serotypes represented in the training set. Next, the performance of the IR Biotyper was assessed using 124 strains representing 59 non-training set serotypes. In this setting, 42 of 59 serotypes (71.1%) could be accurately categorized as being non-training set serotypes. Furthermore, it was observed that comparability of spectra was affected by the source of the Columbia medium used to grow the pneumococci and that this complicated the robustness and standardization potential of FT-IR spectroscopy. A rigorous laboratory workflow in combination with specific ANN models that account for environmental noise parameters can be applied to overcome this issue in the near future. The IR Biotyper has the potential to be used as a fast, cost-effective, and accurate phenotypic serotyping tool for S. pneumoniae.

Pneumococcal conjugate vaccines in Taiwan: optimizing health gains in children and older adults through constrained optimization modeling: Pneumococcal conjugate vaccines optimization in Taiwan

OBJECTIVES

Budgetary constraints force healthcare authorities to set priorities for optimal vaccine interventions. A comprehensive decision-making tool would help inform the best combination and sequence of introduction of vaccines within constrained budgets.

METHODS

Looking at available vaccines against pneumococcal infections in Taiwan (10/13-valent pneumococcal conjugate vaccines [PCV10, PCV13] and 23-valent pneumococcal polysaccharide vaccine [PPV23]), a constrained optimization (CO) model was used to assess the optimal combination of vaccines in children and older adults that would maximize the quality-adjusted life years under predefined budget constraints. Scenario analyses were carried out to evaluate the impact of vaccine efficacy (VE) on the optimized solution.

RESULTS

The CO model demonstrated that the optimal sequence of vaccine introduction was PPV23 in older adults and PCV10 in children. The optimal solution was mostly driven by the potential to reduce disease burden in the older adult population. The VE of PPV23 in older adults and the VE of PCV vaccines against serotype 19A invasive pneumococcal disease had little impact on the optimal solution.

CONCLUSIONS

The CO approach can be used to set priorities for introducing new vaccines while maximizing health gains per age group within the constrained National Vaccine Fund for the prevention of pneumococcal disease in Taiwan.

Clinical and Economic Burden of Pneumococcal Disease Due to Serotypes Contained in Current and Investigational Pneumococcal Conjugate Vaccines in Children Under Five Years of Age

INTRODUCTION

The widespread implementation of pneumococcal conjugate vaccines (PCVs) has significantly reduced the burden of pneumococcal disease around the world. Although licensed 10-valent (PCV10) and 13-valent (PCV13) vaccines have considerably reduced mortality and morbidity, a sizeable disease burden attributable to serotypes not contained in these PCVs remains. This study aimed to estimate the annual clinical and economic burden of pneumococcal disease attributable to licensed (PCV10 and PCV13) and investigational PCVs, notably 15-valent (PCV15) and 20-valent (PCV20) vaccines, in 13 countries in children under 5 years of age.

METHODS

A decision-analytic model was created to aggregate total cases [inclusive of invasive pneumococcal disease (IPD), pneumonia, and otitis media (OM)], deaths, and direct costs in each country of interest [stratified by PCV10/PCV13 countries, depending on national immunization programs (NIPs)] over 1 year, using up to the three most recent years of available serotype coverage data. Data inputs were sourced from local databases, surveillance reports, and published literature.

RESULTS

In 5 PCV10 NIPs (Austria, Finland, Netherlands, New Zealand, Sweden), most remaining PCV20-type disease was due to PCV13-unique serotypes (30-85%), followed by PCV20-unique (9-50%), PCV15-unique (4-15%), and PCV10-unique (2-14%) serotypes. In 8 PCV13 NIPs (Australia, Canada, France, Germany, Italy, South Korea, Spain, United Kingdom), most remaining PCV20-type disease was caused by PCV20-unique serotypes (16-69%), followed by PCV13-unique (11-54%), PCV15-unique (2-33%), and PCV10-unique serotypes (3-19%). Across all countries, PCV20 serotypes caused 3000 to 345,000 cases of disease and cost between $1.3 and $44.9 million USD annually with variability driven by population size, NIP status, and epidemiologic inputs. In aggregate, PCV20 serotypes caused 1,234,000 cases and $213.5 million in annual direct medical costs in children under 5 years of age.

CONCLUSION

Despite the success of PCV10 and PCV13 in reducing pneumococcal disease, a substantial clinical and economic burden remains due to serotypes contained in investigational vaccines.

Cost-Effectiveness of the 13-Valent Pneumococcal Conjugate Vaccine (PCV13) Versus Lower-Valent Alternatives in Filipino Infants

Introduction

The Philippines pediatric national immunization program (NIP) included the 13-valent pneumococcal conjugate vaccine manufactured by Pfizer (PCV13-PFE) since 2015. Uptake has been slow in particular regions, with coverage only reaching all regions in 2019. Given affordability challenges in the context of higher coverage, this study seeks to determine whether universal coverage across all regions of the Philippines with PCV13-PFE will provide good value for money compared with 10-valent PCV alternatives manufactured by GlaxoSmithKline (PCV10-GSK) or Serum Institute of India (PCV10-SII).

Methods

A decision analytic model is adapted for this cost-effectiveness analysis in the Philippines. Clinical and economic input parameters are taken from published sources. Future disease is predicted using age-stratified and population-level observed serotype dynamics. Total cases of pneumococcal disease, deaths, direct and indirect healthcare costs, and quality-adjusted life years (QALYs) gained are discounted 7% annually and modeled for each PCV. Given clinical uncertainty, PCV10-SII outcomes are reported as ranges. Incremental cost-effectiveness ratios (ICERs) are calculated for PCV13-PFE versus lower-valent PCVs (PCV10-GSK or PCV10-SII) from a societal perspective over 10 years.

Results

Nationwide PCV13-PFE use over 10 years is estimated to avert 375,831 more cases, save 53,189 additional lives, and gain 153,349 QALYs compared with PCV10-GSK. This equates to cost-savings of PHP 12.27 billion after vaccine costs are accounted for. Similarly, PCV13-PFE is more effective and cost-saving compared with PCV10-SII. Switching programs to PCV10-SII would result in more cases of disease (313,797 – 666,889), more deaths (22,759 – 72,435), and lost QALYs (108,061 – 266,108), equating to a net economic loss (PHP 359.82 million – 14.41 billion). PCV13-PFE remains cost-effective in the presence of parameter uncertainty.

Conclusion

PCV13-PFE would prevent exceedingly more cases and deaths compared with lower-valent PCVs. Additionally, the PCV13-PFE program is estimated to continue providing cost-savings, offering the best value for money to achieve universal PCV coverage in the Philippines.

Public health impact of pneumococcal conjugate vaccination: a review of measurement challenges

INTRODUCTION

Modeling analyses have attempted to quantify the global impact of pneumococcal conjugate vaccines (PCVs) on pneumococcal disease (PD), however these pediatric models face several challenges in obtaining comprehensive impact measurements.

AREAS COVERED

We present several measurement challenges and discuss examples from recently published pediatric modeling evaluations. Challenges include estimating the number of infants fully or partially vaccinated with PCVs, inclusion of indirect effects of vaccination, accounting for various dosing schedules, capturing effect of PCVs on nonspecific, noninvasive PD, and inclusion of adult PCV use.

EXPERT OPINION

The true impact of PCVs has been consistently underestimated in published analyses due to multiple measurement challenges. Nearly 100 million adults are estimated to have received PCV13 over the last decade globally, potentially preventing up to 662 thousand cases of PD. Approximately 4.1 million cases of invasive PD alone may have been averted through indirect protection. Estimates of PCV impact on noninvasive PD remain a challenge due to altered epidemiology. Program switches, incomplete vaccination, and private market uptake among children also confound PD impact estimates. Taken together, the number of averted PD cases from PCV use in the last ten years may be up to three times higher than estimated in previous studies.

Estimating the Public Health and Economic Impact of Introducing the 13-Valent Pneumococcal Conjugate Vaccine or 10-Valent Pneumococcal Conjugate Vaccines into State Immunization Programs in India

Introduction

Although the pneumococcal conjugate vaccine (PCV) has been introduced into select state immunization programs (SIPs) in India, many children remain unvaccinated. Recently, India’s Advisory Committee on Vaccines & Immunization Practices recommended PCV on the pediatric immunization schedule nationally. This study estimates the public health and economic impact of introducing either Pfizer’s 13-valent PCV (PCV13-PFE), GlaxoSmithKline’s 10-valent PCV (PCV10-GSK), or Serum Institute of India’s 10-valent PCV (PCV10-SII) into every pediatric SIP.

Methods

A model was developed to predict the disease cases, deaths, and costs associated with implementing PCV13-PFE, PCV10-GSK, or PCV10-SII in SIPs compared to no vaccination program across a 5-year period (2021–2025). State and national-level uptake rate and clinical and economic input parameters were collected from published literature. Disease outcomes included invasive pneumococcal disease, inpatient and outpatient pneumonia, and otitis media. Costs were estimated as vaccine-related costs and direct medical costs incurred to the healthcare system. Results were reported by individual state and aggregated nationally.

Results

Estimated over 5 years, implementing PCV13-PFE in SIPs could avert 12.1 million cases and save 626,512 lives among children under 5 years old compared to no vaccination. This corresponds to net national cost savings of over $1.0 billion. Both lower-valent PCVs are estimated to provide less economic savings than PCV13-PFE inclusive of vaccine-related costs. Compared with PCV13-PFE, implementing PCV10-GSK or PCV10-SII nationally is estimated to have a smaller public health impact, with PCV10-GSK averting 8.4 million cases (436,577 deaths) and PCV10-SII preventing 10.3 million cases (531,545 deaths) in India compared to no vaccination, respectively.

Conclusion

Implementation of PCV13-PFE throughout India is estimated to provide greater public health and economic benefits than PCV10-GSK or PCV10-SII SIPs. Our analysis highlights the substantial disease cases, deaths, and health system cost savings that may be realized from implementing PCV programs throughout India.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40121-021-00498-4.

Validation of a Novel Forecasting Method for Estimating the Impact of Switching Pneumococcal Conjugate Programs: Evidence from Belgium

Introduction

Since 2010, 10-valent (PCV10) and 13-valent pneumococcal conjugate vaccines (PCV13) have been available as part of infant national immunization programs. Belgium is as one of the few countries that implemented PCV13 (2007–2015), switched to PCV10 (2015–2018) and then switched back to PCV13 (2018–present) after observing increases in disease. We assessed the impacts of both historical and prospective PCV choice in the context of the Belgian health care system and used this experience to validate previously developed economic models.

Methods

Using historical incidence (2007–2018) of pneumococcal disease for Belgian children aged < 16 years, observed invasive pneumococcal disease (IPD) trends from surveillance data were used to estimate future disease in a given PCV13- or PCV10-based program. We compared observed incidence data with two modeled scenarios: (1) the 2015 switch to PCV10 and (2) a hypothetical continuation of PCV13 in 2015. Finally, we explored the potential impact of PCV choice from 2019 to 2023 by comparing three scenarios: (3) continued use of PCV10; (4) a switch back to PCV13; (5) a hypothetical scenario in which Belgium never switched from PCV13.

Results

Model predictions underestimated observed data from 2015 to 2018 by 100 IPD cases among ages < 16 years. Comparing observed data with scenario 2 suggests that PCV13 would have prevented 105 IPD cases from 2015 to 2018 compared with PCV10. Switching to PCV13 in 2019 would avert 625 IPD cases through 2023 compared with continuing PCV10. Scenario never switching from PCV13 would have resulted in a reduction of 204 cases from 2016 to 2023 compared with switching to PCV10 and switching back to PCV13.

Conclusion

The findings from this study suggest that previously published modeling results of PCV13 versus PCV10 in other countries may have underestimated the benefit of PCV13. These results highlight the importance of continually protecting against vaccine-preventable pneumococcal serotypes.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40121-021-00485-9.

Molecular characterization and epidemiology of Streptococcus pneumoniae serotype 8 in Denmark

Background

Streptococcus pneumoniae serotype 8 incidence has increased in Denmark after the introduction of pneumococcal conjugated vaccines (PCV). The mechanism behind the serotype 8 replacement is not well understood. In this study, we aimed to present epidemiological data on invasive pneumococcal disease (IPD) and molecular characterization of 96 serotype 8 clinical isolates.

Methods

IPD data from 1999 to 2019 were used to calculate the incidence and age distribution. Whole-genome sequencing (WGS) analysis was performed on 96 isolates (6.8% of the total serotype 8 IPD isolates in the period) to characterize the isolates with respect to pneumococcal lineage traits, a range of genes with potential species discrimination, presence of colonization and virulence factors, and molecular resistance pattern.

Results

The serotype 8 IPD incidence increased significantly (P < 0.05) for the age groups above 15 years after the introduction of PCV13, primarily affecting the elderly (65+). All isolates were phenotypically susceptible to penicillin, erythromycin and clindamycin.

Molecular characterization revealed seven different MLST profiles with ST53 as the most prevalent lineage (87.5%) among the analyzed serotype 8 isolates. The genes covering the cell-surface proteins: lytA, rspB, pspA, psaA & Xisco and the pneumococcal toxin pneumolysin = ply were present in all isolates, while genes for the membrane transporter proteins: piaA/piaB/piaC; the capsular genes: cpsA (wzg) & psrP; the metallo-binding proteins zmpB & zmpC; and the neuroamidase proteins: nanA/nanB were variably present. Surprisingly, the putative transcriptional regulator gene SP2020 was not present in all isolates (98%). Susceptibility to penicillin, erythromycin and clindamycin was molecularly confirmed.

Conclusion

The observed serotype 8 replacement was not significantly reflected with a change in the MLST profile or changes in antibiotic resistance- or virulence determinants.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-06103-w.

Exploring the evidence behind the comparable impact of the pneumococcal conjugate vaccines PHiD-CV and PCV13 on overall pneumococcal disease

The worldwide implementation of pneumococcal conjugate vaccines (PCVs) in children has reduced the overall pneumococcal disease burden. Two PCVs are widely available for infant vaccination: the pneumococcal non-typeable Haemophilus influenzae protein D conjugate vaccine (PHiD-CV) and the 13-valent PCV (PCV13). While these PCVs differ in serotype composition (PCV13 includes polysaccharides of serotypes 3, 6A and 19A; PHiD-CV does not), their impact on the overall pneumococcal disease burden in children is comparable. This commentary summarizes the evidence of comparability between PHiD-CV and PCV13 and explores why differences in serotype composition may not necessarily translate into a differential clinical impact. Both vaccines confer similarly high protection against disease caused by vaccine serotypes and lead to a partial replacement by non-vaccine serotypes. PHiD-CV does not protect against serotype 3 disease (not included in the vaccine) and PCV13’s effect on this serotype has been inconsistent. PHiD-CV provides some cross-protection against disease caused by vaccine-related serotype 19A but neither vaccine has fully controlled 19A disease. While protection against 19A is higher for PCV13 than PHiD-CV, replacement by non-PCV13 serotypes in settings with a PCV13 program appears to compensate for this difference. This results in a similar residual overall disease burden with both vaccines.

What is the context?

The pneumococcus bacterium can cause infections of the meninges, blood, lung, middle ear and sinuses.

Two vaccins, Synflorix (GSK) and Prevnar 13 (Pfizer Inc.), are widely used to protect young children against these infections.

The vaccines’ compositions differ: Synflorix includes antigens from 10 pneumococcus strains (or “serotypes”) and Prevnar 13 from 13 serotypes.

However, both have a similar effect on the total pneumococcal disease burden in children.

What does this commentary highlight?

This commentary summarizes the evidence beihnd the two vaccines’ comparable impact on pneumococcal disase.

It also looks at why the vaccines have a similar effect on the total pneumococcal disease burden despite their different compositions.

What is the impact on current thinking?

Given that Synflorix and Prevnar 13 have a comparable impact on pneumococcal disease, a country’s choice between the two vaccines will depend on vaccine supply, cost, logistical factors (e.g., transport, storage, training requirements of health workers) and the local pneumococcal epidemiology.

Burden of invasive pneumococcal disease (IPD) over a 10-year period in Bogotá, Colombia

BACKGROUND

Invasive pneumococcal disease (IPD) is the leading cause of infectious death worldwide. This study aimed to describe the epidemiology of IPD and the impact of pneumococcal conjugate vaccine-10 (PCV-10) over a 10-year period in Bogotá, Colombia.

METHODS

This was a laboratory-based surveillance study of Streptococcus pneumoniae isolated from patients with IPD from 82 hospitals over 10 years in Bogotá, Colombia. Data were compared between two periods: 2007-2011 (before the introduction of PCV-10) and 2012-2017 (after the introduction of PCV-10).

RESULTS

In total, 1670 patients with IPD were included in the study between 2007 and 2017. Between 2007 and 2011, the most common serotypes were 14, 1, 6B, 6A and 3. Between 2012 and 2017, the most common serotypes were 19A, 3, 14 and 1. A decrease in the incidence of IPD, particularly in children aged 0-4 years, was noted after the introduction of PCV-10. Importantly, this reduction in incidence was not observed in patients aged ≥50 years.

CONCLUSIONS

The IPD burden in Bogotá remained stable between 2007 and 2017. The incidence of IPD decreased in children but not in older adults. The introduction of PCV-10 led to a change in the most prevalent serotypes to serotypes that are not included in PCV-10.

Pneumococcal Pneumonia and Invasive Pneumococcal Disease in Those 65 and Older: Rates of Detection, Risk Factors, Vaccine Effectiveness, Hospitalisation and Mortality

Pneumococcal pneumonia (PP) and invasive pneumococcal disease (IPD) are important causes of morbidity and mortality in seniors worldwide. Incidence rates and serious outcomes worsen with increasing frailty, numbers of risk factors and decreasing immune competence with increasing age. Literature reviews in Medline and Embase were performed for pneumococcal disease incidence, risk factors, vaccination rates and effectiveness in the elderly. The introduction of protein-conjugated pneumoccal vaccines (PCV) for children markedly reduced IPD and PP in seniors, but serotypes not included in vaccines and with previously low levels increased. Pneumococcal polysaccharide (PPV23) vaccination does not change nasal and pharyngeal carriage rates. Pneumococcal and influenza vaccination rates in seniors are below guideline levels, especially in older seniors and nursing home staff. Pneumococcal and influenza carriage and vaccination rates of family members, nursing home health care workers and other contacts are unknown. National vaccination programmes are effective in increasing vaccination rates. Detection of IPD and PP initially depend on clinical symptoms and new chest X ray infiltrates and then varies according to the population and laboratory tests used. To understand how seniors and especially older seniors acquire PP and IPD data are needed on pneumococcal disease and carriage rates in family members, carers and contacts. Nursing homes need reconfiguring into small units with air ventilation externally from all rooms to minimise respiratory disease transmission and dedicated staff for each unit to minimise transmision of infectious diseaases.

Can two different pneumococcal conjugate vaccines be used to complete the infant vaccination series? A randomized trial exploring interchangeability of the 13-valent pneumococcal conjugate vaccine and the pneumococcal non-typeable Haemophilus influenzae protein D-conjugate vaccine

Background: We assessed the safety and immunogenicity of 2 + 1 infant regimens initiated with the 13-valent pneumococcal conjugate vaccine (PCV13) and completed with the pneumococcal non-typeable Haemophilus influenzae protein D-conjugate vaccine (PHiD-CV). Methods: This partially blinded study randomized 6-12-week-old infants to receive two-dose priming and a booster (at ages 2, 4, 12-15 months) with: PCV13 at priming and PHiD-CV at boosting (PPS); PCV13 then PHiD-CV at priming and PHiD-CV at boosting (PSS); or PHiD-CV at priming and boosting (SSS control). All analyses were descriptive, i.e., no statistical significance tests were done. Results: The total vaccinated cohort at priming comprised 294 infants. Grade 3 adverse events were reported after 8.7% (PPS), 11.4% (PSS), and 16.9% (SSS) of primary doses (primary objective). No serious adverse events were considered vaccination-related. For most PHiD-CV serotypes, observed percentages of children reaching antibody concentrations ≥0.2 µg/mL and opsonophagocytic activity (OPA) titers above cutoffs were similar across groups 1 month post-priming and post-booster. Observed geometric mean antibody concentrations and OPA titers were lower for some PHiD-CV serotypes with the mixed regimens than with PHiD-CV only, especially for PSS. However, no tests of statistical significance were performed. Conclusions: Immunogenicity of the two mixed PCV13/PHiD-CV regimens seemed mostly similar to that of a PHiD-CV-only series, although observed antibody GMCs and OPA GMTs for some PHiD-CV serotypes were lower. No safety concerns were raised. The clinical relevance of the observed differences is unknown. Clinical trial registration: ClinicalTrials.gov: NCT01641133.