Invasive pneumococcal disease due to 22F and 33F in England: A tail of two serotypes

Immunogenicity and safety of a 14-valent pneumococcal polysaccharide conjugate vaccine (PNEUBEVAX 14™) administered to 6-8 weeks old healthy Indian Infants: A single blind, randomized, active-controlled, Phase-III study

BACKGROUND

Introduction of pneumococcal conjugate vaccines (PCVs) reduced the number of cases of pneumococcal disease (PD). However, there is an increase in clinical and economic burden of PD from serotypes that are not part of the existing pneumococcal vaccines, particularly impacting pediatric and elder population. In addition, the regions where the PCV is not available, the disease burden remains high. In this study, immunogenicity and safety of the BE's 14-valent PCV (PNEUBEVAX 14™; BE-PCV-14) containing two additional epidemiologically important serotypes (22F and 33F) was evaluated in infants in comparison to licensed vaccine, Prevenar-13 (PCV-13).

METHODS

This is a pivotal phase-3 single blind randomized active-controlled study conducted at 12 sites across India in 6-8 weeks old healthy infants at 6-10-14 weeks dosing schedule to assess immunogenic non-inferiority and safety of a candidate BE-PCV-14. In total, 1290 infants were equally randomized to receive either BE-PCV-14 or PCV-13. Solicited local reactions and systemic events, adverse events (AEs), serious AEs (SAEs), and medically attended AEs (MAAEs) were recorded. Immunogenicity was assessed by measuring anti-PnCPS (anti-pneumococcal capsular polysaccharide) IgG concentration and functional antibody titers through opsonophagocytic activity (OPA), one month after completing three dose schedule. Cross protection to serotype 6A offered by serotype 6B was also assessed in this study.

FINDINGS

The safety profile of BE-PCV-14 was comparable to PCV-13 vaccine. Majority of reported AEs were mild in nature. No severe or serious AEs were reported in both the treatment groups. For the twelve common serotypes and for the additional serotypes (22F and 33F) in BE-PCV-14, NI criteria was demonstrated as defined by WHO TRS-977. Primary immunogenicity endpoint was met in terms of IgG immune responses for all 14 serotypesof BE-PCV-14. Moreover, a significant proportion of subjects (69%) seroconverted against serotype 6A, even though this antigen was not present in BE-PCV-14. This indicates that serotype 6B of BE-PCV-14 cross protects serotype 6A. BE-PCV-14 also elicited comparable serotype specific functional OPA immune responses to all the serotypes common to PCV-13.

INTERPRETATIONS

BE-PCV-14 was found to be safe and induced robust and functional serotype specific immune responses to all 14 serotypes. It also elicited cross protective immune response against serotype 6B.These findings suggest that BE-PCV-14 can be safely administered to infants and achieve protection against pneumococcal disease caused by serotypes covered in the vaccine. The study was prospectively registered with clinical trial registry of India - CTRI/2020/02/023129.

Phase 3 trial to evaluate the safety, tolerability, and immunogenicity of V114, a 15-valent pneumococcal conjugate vaccine, followed by 23-valent pneumococcal polysaccharide vaccine 6 months later, in at-risk adults 18-49 years of age (PNEU-DAY): A subgroup analysis by baseline risk factors

Immunocompetent adults with certain medical and behavioral factors are at increased risk of pneumococcal disease. In some countries, sequential vaccination with 13-valent pneumococcal conjugate vaccine (PCV13) followed by 23-valent pneumococcal polysaccharide vaccine (PPSV23) is recommended for at-risk adults. This subgroup analysis from a phase 3 study evaluated the safety, tolerability, and immunogenicity of sequential administration of either V114 (a 15-valent PCV containing serotypes 1, 3, 4, 5, 6A, 6B, 7F, 9V, 14, 18C, 19A, 19F, 22F, 23F, and 33F) or PCV13, followed 6 months later by PPSV23, in immunocompetent adults 18-49 years of age with pre-defined risk factors for pneumococcal disease. Safety and immunogenicity post-vaccination were analyzed by type and baseline number of risk factors for pneumococcal disease (1 and ≥2 risk factors). This analysis included 1,131 participants randomized 3:1 to receive either V114 or PCV13, followed by PPSV23. The majority (73.1%) of participants had at least one risk factor. Safety and tolerability profiles of V114 and PCV13 were similar across risk factor groups. V114 administered either alone or sequentially with PPSV23 6 months later was immunogenic for all 15 serotypes, including those not contained in PCV13, regardless of the number of baseline risk factors. V114 has the potential to broaden serotype coverage for at-risk adults.

Pneumococcal Serotype Evolution and Burden in European Adults in the Last Decade: A Systematic Review

Pneumococcal disease is a major cause of morbidity/mortality worldwide, and vaccination is an important measure in its prevention. Despite European children being vaccinated with pneumococcal conjugate vaccines (PCVs), pneumococcal infections are still a major cause of morbidity/mortality in adults with risk conditions and their vaccination might be an important prevention strategy. New PCVs have been approved, but information is lacking on their potential impact in European adults. In our review, we searched PubMed, MEDLINE, and Embase for studies on the additional PCV20 serotypes (concerning incidence, prevalence, disease severity, lethality, and antimicrobial resistance) in European adults, between January 2010 and April 2022, having included 118 articles and data from 33 countries. We found that these serotypes have become more prevalent in both invasive and non-invasive pneumococcal disease (IPD and NIPD), representing a significant proportion of cases (serotypes 8, 12F, 22F) and more serious disease and/or lethality (10A, 11A, 15B, 22F), showing antimicrobial resistance (11A, 15B, 33F), and/or affecting more vulnerable individuals such as the elderly, immunocompromised patients, and those with comorbidities (8, 10A, 11A, 15B, 22F). The relevance of pneumococcal adult carriers (11A, 15B, 22F, and 8) was also identified. Altogether, our data showed an increase in the additional PCV20 serotypes' prevalence, accounting for a proportion of approximately 60% of all pneumococcal isolates in IPD in European adults since 2018/2019. Data suggest that adults, as older and/or more vulnerable patients, would benefit from vaccination with higher-coverage PCVs, and that PCV20 may address an unmet medical need.

Nasopharyngeal Carriage of Pneumococcus in Children in England up to 10 Years After 13-Valent Pneumococcal Conjugate Vaccine Introduction: Persistence of Serotypes 3 and 19A and Emergence of 7C

BACKGROUND

Monitoring changes in pharyngeal carriage of pneumococcus in children following 13-valent pneumococcal conjugate vaccine (PCV13) introduction in the United Kingdom in 2010 informs understanding of patterns of invasive pneumococcal disease (IPD) incidence.

METHODS

Nasopharyngeal swabs from healthy children vaccinated with PCV13 according to schedule (2, 4, and 12 months) were cultured and serotyped. Results for children aged 13-48 months were compared between 2014-2015 and 2017-2019 and with children aged 6-12 months (2017-2020). Blood was obtained from a subset of children for pneumococcal serotype-specific immunoglobulin G (IgG).

RESULTS

Total pneumococcal carriage at 13-48 months was 47.9% (473/988) in 2014-2015 and 51.8% (412/795) in 2017-2019 (P = .10); at age 6-12 months this value was 44.6% (274/615). In 2017-2019, 2.9% (95% confidence interval, 1.8%-4.3%) of children aged 13-48 months carried PCV13 serotypes (mainly 3 [1.5%] and 19A [0.8%]) and >20% carried the additional 20-valent PCV (PCV20) serotypes. Similar proportions of children had IgG ≥0.35 IU/mL for each serotype in 2014-2015 and 2017-2019. Serotype 7C carriage increased significantly (P < .01) between 2014-2015 and 2017-2019. Carriage of PCV20 serotypes 8 and 12F, both major causes of IPD, was rare.

CONCLUSIONS

Introduction of PCV20, if licensed for children, could significantly change the composition of pneumococcal serotypes carried in the pharynx of UK children.

CLINICAL TRIALS REGISTRATION

NCT03102840.

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.

Invasive Pneumococcal Disease Characterization in Adults and Subgroups aged < 60 years and ≥ 60 years in Bogota, Colombia

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The clinical burden of IPD is high in the elderly and adults with comorbidities

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IPD placed a high burden on healthcare resources in the adult population

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The most common types causing IPD in adults were similar to those found in children

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Policy makers should consider pneumococcal vaccination for populations at risk

Background

Methods

Results

Conclusions

Pneumococcal Serotype Identification by Capsular Sequence Typing (CST): A Modified Novel Approach for Serotyping Directly in Clinical Samples

As almost 60-70% of Invasive Pneumococcal Disease (IPD) is identified by nonculture methods in Greece, serotyping is of high importance for the better monitoring of pneumococcal serotypes due to the availability of conjugate vaccines. The aim of the study was the modification and direct application of the Capsular Sequence Typing (CST) assay in clinical samples in order to serotype Streptococcus pneumoniae culture-negative, Polymerase Chain Reaction (PCR_-positive samples, followed by CST group specific single-tube PCR assays. A two-step PCR modified assay was applied on a total of 306 samples (such as CSF, blood, pleural and middle ear fluids, isolates) obtained from 283 patients with IPD. The overall performance permits a rapid, accurate and cost-effective method for nonculture pneumococcal serotyping. As the management of IPD is closely related to the continuous monitoring of pneumococcal serotypes, the proposed approach proved to be a valuable tool for the typing and epidemiological monitoring of S. pneumoniae, for the evaluation of the overall impact of vaccination programs in the era of pneumococcal conjugate vaccines, in order to initiate the appropriate vaccination strategy.

Streptococcus Pneumoniae septic arthritis in adults in Bristol and Bath, United Kingdom, 2006-2018: a 13-year retrospective observational cohort study

Few studies on adult pneumococcal septic arthritis are sufficiently large enough to assess both epidemiological trends following routine pneumococcal immunization and clinical disease. With major shifts in serotypes causing invasive pneumococcal disease (IPD), we wanted to determine the clinical phenotype of adult septic arthritis caused by Streptococcus pneumoniae. We conducted a retrospective cohort study of pneumococcal infections in Bristol and Bath, UK, 2006–2018. We defined pneumococcal septic arthritis as adults with clinically-confirmed septic arthritis, with pneumococcus isolated from sterile-site culture or urinary antigen test positivity. Clinical records were reviewed for each patient in the cohort. Septic arthritis accounted for 1.7% of all IPD cases. 45 cases of adult pneumococcal septic arthritis occurred, with disease typically affecting older adults and those with underlying comorbidity. 67% patients had another focus of infection during their illness. 66% patients required increased care on discharge and 43% had reduced range of movement. In-hospital case fatality rate was 6.7%. One-year patient mortality was 31%. Currently most cases of adult pneumococcal septic arthritis are due to non-PCV13 serotypes which are associated with more severe disease. Non-PCV-13 serotypes had higher prevalence of concomitant pneumococcal infection at another site (73.7% versus 36.6%), increased intensive care or high-dependency unit requirement (32.4% versus 0%), and increased inpatient and 1-year case fatality rate (8.8% versus 0%, and 32.4% versus 27.4% respectively) compared to PCV-13 serotypes. Pneumococcal septic arthritis remains a small proportion of IPD. However, there is significant associated morbidity and mortality, and pneumococcal septic arthritis requires monitoring in coming years.