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

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.

Clinical and economic burden of acute otitis media caused by Streptococcus pneumoniae in European children, after widespread use of PCVs-A systematic literature review of published evidence

BACKGROUND

Acute otitis media (AOM) is a common childhood disease frequently caused by Streptococcus pneumoniae. Pneumococcal conjugate vaccines (PCV7, PCV10, PCV13) can reduce the risk of AOM but may also shift AOM etiology and serotype distribution. The aim of this study was to review estimates from published literature of the burden of AOM in Europe after widespread use of PCVs over the past 10 years, focusing on incidence, etiology, serotype distribution and antibiotic resistance of Streptococcus pneumoniae, and economic burden.

METHODS

This systematic review included published literature from 31 European countries, for children aged ≤5 years, published after 2011. Searches were conducted using PubMed, Embase, Google, and three disease conference websites. Risk of bias was assessed with ISPOR-AMCP-NPC, ECOBIAS or ROBIS, depending on the type of study.

RESULTS

In total, 107 relevant records were identified, which revealed wide variation in study methodology and reporting, thus limiting comparisons across outcomes. No homogenous trends were identified in incidence rates across countries, or in detection of S. pneumoniae as a cause of AOM over time. There were indications of a reduction in hospitalization rates (decreases between 24.5-38.8% points, depending on country, PCV type and time since PCV introduction) and antibiotic resistance (decreases between 14-24%, depending on country), following the widespread use of PCVs over time. The last two trends imply a potential decrease in economic burden, though this was not possible to confirm with the identified cost data. There was also evidence of an increase in serotype distributions towards non-vaccine serotypes in all of the countries where non-PCV serotype data were available, as well as limited data of increased antibiotic resistance within non-vaccine serotypes.

CONCLUSIONS

Though some factors point to a reduction in AOM burden in Europe, the burden still remains high, residual burden from uncovered serotypes is present and it is difficult to provide comprehensive, accurate and up-to-date estimates of said burden from the published literature. This could be improved by standardised methodology, reporting and wider use of surveillance systems.

Potential serotype-specific effectiveness against IPD of pneumococcal conjugate vaccines V114 and PCV20 in children given a 2+1 dosing regimen

BACKGROUND

Next generation, higher valency pneumococcal conjugate vaccines (PCVs) are assessed and licensed by comparing the immune response across serotypes shared with the PCVs that are standard of care for prevention of pneumococcal disease.

METHODS

Using a previously qualified method we predicted the serotype-specific vaccine effectiveness (VE) against invasive pneumococcal disease of V114 and PCV20 for the serotypes shared with PCV13 in an EU, Russian, and Australian pediatric population that is recommended to receive a 2 + 1 dosing regimen.

RESULTS

The estimated protective antibody concentrations ranged from 0.03 (serotype 23F) to 1.49 µg/mL (serotype 19F). Predicted VE values for V114 ranged from 79% (serotype 5) to 100% (serotype 23F). V114 had comparable effectiveness to PCV13 for all but one of shared serotypes, with predicted higher effectiveness (in V114) against serotype 3 (93% vs. 65%). Predicted VE values for PCV20 ranged from 47% (serotype 3) to 91% (serotype 14). PCV20 predicted VE was lower than PCV13's for serotypes 4, 19F, 23F, 1, 3, 5, 6A, 7F, and 19A.

CONCLUSIONS

Predicted serotype-specific VE values suggest that, with a 2 + 1 dosing regimen, V114 will have greater effectiveness than PCV20 against PCV13 serotypes, particularly for the still-prevalent serotype 3. Real-world VE studies will ultimately provide clarity on the effectiveness of novel PCVs and support further confidence in and/or improvements to modeling efforts.

Recent changes to adult national immunization programs for pneumococcal vaccination in Europe and how they impact coverage: A systematic review of published and grey literature

Despite widespread use of pneumococcal vaccines throughout Europe, the burden of pneumococcal disease (PD) in adults is considerable. To mitigate this burden, National Immunization Technical Advisory Groups (NITAGs) and Health Technology Assessment (HTA) agencies assess the value of different vaccine schedules for protecting against PD. The aim of this review was to assess the evidence and rationales used by NITAGs/HTA agencies, when considering recent changes to National Immunization Programs (NIPs) for adults, and how identified changes affected vaccine coverage rates (VCRs). A systematic review was conducted of published literature from PubMed® and Embase®, and gray literature from HTA/NITAG websites from the last 5 y, covering 31 European countries. Evidence related to NIP recommendations, epidemiology (invasive PD, pneumonia), health economic assessments and VCRs were collected and synthesized. Eighty-four records providing data for 26 countries were identified. Of these, eight described explicit changes to NIPs for adults in seven countries. Despite data gaps, some trends were observed; first, there appears to be a convergence of NIP recommendations in many countries toward sequential vaccination, with a pneumococcal conjugate vaccine (PCV), followed by pneumococcal polysaccharide vaccine 23. Second, reducing economic or healthcare burden were common rationales for implementing changes. Third, most health economic analyses assessing higher-valency PCVs for adults found its inclusion in NIPs cost-effective. Finally, higher coverage rates were seen in most cases where countries had expanded their NIPs to cover at-risk populations. The findings can encourage agencies to improve surveillance systems and work to reach the NIP's target populations more effectively.

Estimating the Clinical and Economic Impact of Switching from the 13-Valent Pneumococcal Conjugate Vaccine (PCV13) to Higher-Valent Options in Greek Infants

In June 2010, Greece introduced the 13-valent pneumococcal conjugate vaccine (PCV13) for pediatric vaccination and has since observed a large decrease in pneumococcal disease caused by these vaccine serotypes, yet the disease prevalence of non-vaccine serotypes has increased. Two higher-valent conjugate vaccines, a 15-valent (PCV15) and a 20-valent (PCV20), were developed to improve serotype coverage and combat serotype replacement. A decision-analytic model was adapted to the Greek setting using historical pneumococcal disease trends from PCV13 to forecast future clinical and economic outcomes of higher-valent PCVs over a 10-year period (2023-2033). The model estimated outcomes related to invasive pneumococcal disease (IPD), hospitalized and non-hospitalized pneumonia, and otitis media (OM) resulting from a switch in vaccination programs to PCV15 in 2023 or switching to PCV20 in 2024. Cost-effectiveness was evaluated from the third-party payer's perspective in the Greek healthcare system. Compared to implementing PCV15 one year earlier, switching from PCV13 to PCV20 in 2024 was estimated to be a cost-saving strategy by saving the Greek health system over EUR 50 million in direct medical costs and averting over 250 IPD cases, 54,800 OM cases, 8450 pneumonia cases, and 255 deaths across all ages over a 10-year period.

Estimating the Cost-Effectiveness of Switching to Higher-Valency Pediatric Pneumococcal Conjugate Vaccines in the United Kingdom

Currently, the 13-valent pneumococcal conjugate vaccine (PCV13) is administered under a 1+1 (1 primary dose) pediatric schedule in the United Kingdom (UK). Higher-valency PCVs, 15-valent PCV (PCV15), or 20-valent PCV (PCV20) might be considered to expand serotype coverage. We evaluated the cost-effectiveness of PCV20 or PCV15 using either a 2+1 (2 primary doses) or 1+1 schedule for pediatric immunization in the UK. Using a dynamic transmission model, we simulated future disease incidence and costs under PCV13 1+1, PCV20 2+1, PCV20 1+1, PCV15 2+1, and PCV15 1+1 schedules from the UK National Health Service perspective. We prospectively estimated disease cases, direct costs, quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratio. Scenario analyses were performed to estimate the impact of model assumptions and parameter uncertainty. Over a five-year period, PCV20 2+1 averted the most disease cases and gained the most additional QALYs. PCV20 2+1 and 1+1 were dominant (cost-saving and more QALYs gained) compared with PCV15 (2+1 or 1+1) and PCV13 1+1. PCV20 2+1 was cost-effective (GBP 8110/QALY) compared with PCV20 1+1. PCV20 was found cost-saving compared with PCV13 1+1, and PCV20 2+1 was cost-effective compared with PCV20 1+1. Policymakers should consider the reduction in disease cases with PCV20, which may offset vaccination costs.

Historical Population-Level Impact of Infant 13-Valent Pneumococcal Conjugate Vaccine (PCV13) National Immunization Programs on Invasive Pneumococcal Disease in Australia, Canada, England and Wales, Israel, and the United States

INTRODUCTION

This study estimates the annual population-level impact of 13-valent pneumococcal conjugate vaccine (PCV13) infant national immunization programs (NIPs) on vaccine-type and non-vaccine type invasive pneumococcal disease (IPD) incidence across all ages using national surveillance data.

METHODS

We identified countries (Australia, Canada, England and Wales, Israel, and the US) with national IPD active surveillance data that introduced the seven-valent PCV (PCV7) followed by PCV13, which also reported annual serotype- and age group-specific incidence. We extracted IPD incidence by serotype groupings [PCV13 minus PCV7 (PCV13-7) serotypes; PCV13-7 serotypes excluding serotype 3; non-PCV13 serotypes; and the 20-valent (PCV20) minus PCV13 (PCV20-13) serotypes] and by age groups (< 2 years, 2-4 years, 5-17 years, 18-34 years, 35-49 years, 50-64 years, and ≥ 65 years). For each country, we calculated the annual relative change in IPD incidence (percent change), and the corresponding incidence rate ratio (IRR), for 7 years post introduction compared to the year prior to PCV13 program initiation.

RESULTS

PCV13-7 vaccine-type IPD incidence consistently decreased over time following introduction of PCV13 across countries, reaching an approximate steady state after 3-4 years in ages < 5 years, with roughly 60-90% decrease (IRRs = 0.1-0.4) and after 4-5 years in ages ≥ 65 years with approximately 60-80% decrease (IRRs = 0.2-0.4). Incidence declines were more substantial for the PCV13-7 grouping when excluding serotype 3. Non-PCV13 serotype incidence was variable by country and age group, ranging from virtually no serotype replacement compared to the PCV7 period across ages in the US to increases for other countries ranging from 10 to 204% (IRRs = 1.10-3.04) in children < 5 years and 41% to 123% (IRRs = 1.41-2.23) in ages ≥ 65 years.

CONCLUSIONS

Countries with longstanding PCV13 infant NIPs have observed substantial direct and indirect benefits, which are demonstrated in this study by the reduction in PCV13-7 IPD incidence compared to PCV7 period in all age groups. Over time, non-PCV13 serotypes have emerged in response to the reduction of incidence of PCV13-unique serotypes. Higher-valent PCVs are needed to address this emerging pneumococcal disease burden as well as the direct vaccination of both pediatric and adult populations against the most prevalent circulating serotypes.

Reanalysis of the Clinical and Economic Burden of Pneumococcal Disease Due to Serotypes Contained in Current and Investigational Pneumococcal Conjugate Vaccines in Children < 5 Age: A Societal Perspective

INTRODUCTION

Studies that estimate the economic burden of pediatric pneumococcal disease often only report direct medical costs and omit indirect non-medical costs. Given these indirect costs are not included in most calculations, the full economic burden attributable to pneumococcal conjugate vaccine (PCV) serotypes is often underestimated. This study seeks to quantify the full broader economic burden of pediatric pneumococcal disease associated with PCV serotypes.

METHODS

We conducted a reanalysis of a previous study where non-medical costs associated with caregiving for a child with pneumococcal disease are considered. The annual indirect non-medical economic burden attributed to PCV serotypes was subsequently calculated for 13 countries. We included five countries with 10-valent (PCV10) national immunization programs (NIPs) (Austria, Finland, The Netherlands, New Zealand, and Sweden) and eight countries with 13-valent (PCV13) NIPs (Australia, Canada, France, Germany, Italy, South Korea, Spain, and the UK). Input parameters were derived from published literature. Indirect costs were inflated to 2021 values in US dollars (USD).

RESULTS

The total annual indirect economic burden associated with pediatric pneumococcal diseases attributable to PCV10, PCV13, the 15-valent (PCV15), and the 20-valent (PCV20) serotypes were $46.51 million, $158.95 million, $223.00 million, and $413.97 million, respectively. The five countries with PCV10 NIPs bear a greater societal burden associated with PCV13 serotypes, whereas the residual societal burden in the eight countries with PCV13 NIPs was primarily attributable to non-PCV13 serotypes.

CONCLUSION

The inclusion of non-medical costs nearly tripled the total economic burden compared with only including direct medical costs estimated from a previous study. The results from this reanalysis can help inform decision-makers on the broader economic societal burden associated with PCV serotypes and the need for higher-valent PCVs.

The impact of vaccination on the burden of invasive pneumococcal disease from a nationwide surveillance program in Lebanon: an unexpected increase in mortality driven by non-vaccine serotypes

BACKGROUND

The impact of pneumococcal conjugate vaccines (PCVs) on the burden of invasive pneumococcal disease (IPD) and serotype distribution was examined across age groups from data collected by the Lebanese Inter-Hospital Pneumococcal Surveillance Program.

METHODS

Between 2005 and 2020, 593 invasive Streptococcus pneumoniae isolates were collected from 79 hospitals throughout Lebanon. Serotypes and antimicrobial resistance (AMR) profiles were identified, and trends compared over 3 eras: PCV7, post-PCV7/ pre-PCV13, and PCV13 eras.

RESULTS

The prevalence of PCV7 serotypes decreased significantly from 43.6% in the PCV7 era to 17.8% during the PCV13 era (p<0.001). PCV13-only serotypes remained stable in the PCV13 compared to the post-PCV7 eras, especially serotypes 1 and 3, whereas non-vaccine types (NVT) increased throughout the study period, especially 24 and 16F. The mortality rate increased substantially from 12.5% (PCV7 era) to 24.8% (PCV13 era). A significant decrease in AMR was observed across the three study eras.

CONCLUSION

PCVs substantially impacted IPD and AMR in vaccinated and unvaccinated populations despite an increase in mortality driven by NVT. Broadening the recommendation of vaccination to include older age-groups, using higher valency vaccines, and implementing stringent antimicrobial stewardship are likely to further impact the burden of IPD.

Predicting effectiveness of the V114 vaccine against invasive pneumococcal disease in children

BACKGROUND

The potential impact of new pneumococcal conjugate vaccines (PCVs) is assessed by using immune responses to predict their effectiveness against invasive pneumococcal disease (IPD). This analysis predicted the serotype-specific effectiveness against IPD of a new 15-valent PCV (V114) for the serotypes shared with a 13-valent PCV (PCV13), in a US pediatric population given a 3 + 1 dosing regimen.

METHODS

Beginning with the known serotype-specific antibody concentrations after vaccination with placebo, 7-valent PCV (PCV7) and PCV13, reverse cumulative distribution curves were used, along with published serotype-specific vaccine effectiveness of PCV7 and PCV13, to derive a protective antibody concentration (C_p) for each PCV13 serotype in V114. Serotype-specific effectiveness was predicted using the C_p estimates and the respective serotype-specific antibody concentrations of placebo and V114 recipients in recent pediatric clinical trials.

RESULTS

Predicted serotype-specific V114 effectiveness values ranged from 86% to 99% for PCV7 serotypes and from 59% to 97% for (non-PCV7) PCV13 serotypes.

CONCLUSIONS

V114 serotype-specific effectiveness against IPD in a US pediatric population was predicted to be largely comparable to that of PCV7 and PCV13 for shared serotypes, with models suggesting likelihood of high overall benefit gained from increased serotype 3 effectiveness, and additional protection against serotypes 22 F and 33 F.

Modeling of pneumococcal serogroup 10 capsular polysaccharide molecular conformations provides insight into epitopes and observed cross-reactivity

Streptococcus pneumoniae is an encapsulated gram-negative bacterium and a significant human pathogen. The capsular polysaccharide (CPS) is essential for virulence and a target antigen for vaccines. Although widespread introduction of pneumococcal conjugate vaccines (PCVs) has significantly reduced disease, the prevalence of non-vaccine serotypes has increased. On the basis of the CPS, S. pneumoniae serogroup 10 comprises four main serotypes 10A, 10B, 10C, and 10F; as well as the recently identified 10D. As it is the most prevalent, serotype 10A CPS has been included as a vaccine antigen in the next generation PCVs. Here we use molecular modeling to provide conformational rationales for the complex cross-reactivity reported between serotypes 10A, 10B, 10C, and 10F anti-sera. Although the highly mobile phosphodiester linkages produce very flexible CPS, shorter segments are conformationally defined, with exposed β-D-galactofuranose (β DGalf) side chains that are potential antibody binding sites. We identify four distinct conformational epitopes for the immunodominant β DGalf that assist in rationalizing the complex asymmetric cross-reactivity relationships. In particular, we find that strongly cross-reactive serotypes share common epitopes. Further, we show that human intelectin-1 has the potential to bind the exposed exocyclic 1,2-diol of the terminal β DGalf in each serotype; the relative accessibility of three- or six-linked β DGalf may play a role in the strength of the innate immune response and hence serotype disease prevalence. In conclusion, our modeling study and relevant serological studies support the inclusion of serotype 10A in a vaccine to best protect against serogroup 10 disease.