Pneumococcal Polysaccharide Conjugate Vaccine Research Articles

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

BackgroundIntroduction 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). MethodsThis 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. FindingsThe 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. InterpretationsBE-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.

In vivo functional immunoprotection correlates for vaccines against invasive bacteria

Vaccination has significantly reduced the incidence of invasive infections caused by several bacterial pathogens, including Streptococcus pneumoniae, Haemophilus influenzae, and Neisseria meningitidis. However, no vaccines are available for many other invasive pathogens. A major hurdle in vaccine development is the lack of functional markers to quantify vaccine immunity in eliminating pathogens during the process of infection. Based on our recent discovery of the liver as the major organ of vaccine-induced clearance of blood-borne virulent bacteria, we here describe a new vaccine evaluation system that quantitatively characterizes the key features of effective vaccines in shuffling virulent bacteria from the blood circulation to the liver resident macrophage Kupffer cells (KCs) and sinusoidal endothelial cells (LSECs) in mouse septic infection model. This system consists of three related correlates or assays: pathogen clearance from the bloodstream, pathogen trapping in the liver, and pathogen capture by KCs/LSECs. These readouts were consistently associated with the serotype-specific immunoprotection levels of the 13-valent pneumococcal polysaccharide conjugate vaccine (PCV13) against lethal infection of S. pneumoniae, a major invasive Gram-positive pathogen of community-acquired infections in humans. Furthermore, the reliability and sensitivity of these correlates in reflecting vaccine efficacy were verified with whole cell vaccines of Klebsiella pneumoniae and Escherichia coli, two major Gram-negative pathogens in hospital-acquired invasive infections. This system may be used as effective readouts to evaluate the immunoprotective potential of vaccine candidates in the preclinical phase by filling the current technical gap in vaccine evaluation between the conventional in vitro approaches (e.g. antibody production and pathogen neutralization/opsonophagocytosis) and survival of immunized animals.

Effectiveness of 13-valent pneumococcal conjugate vaccine against invasive disease caused by serotype 19A in children: a meta-analysis

Objective: Using Meta-analysis to evaluate the vaccine effectiveness of 13-valent pneumococcal conjugate vaccine (PCV13) against invasive Streptococcus pneumoniae disease (IPD) caused by serotype 19A in children <5 years old. Methods: "Streptococcus pneumoniae infection""invasive pneumococcal disease""13-valent pneumococcal polysaccharide conjugate vaccine""PCV13""effectiveness""infant""child" and related terms were searched from China National Knowledge Infrastructure (CNKI), WANFANG DATA, PubMed, SCOPUS and Web of science with no limited on language, region and research institution. The retrieval time was limited from January 2010 to February 2023 and cohort study, case-control study and randomized controlled trial were included. Data were extracted from eligible studies by two independent reviewers, and after study quality assessment by NOS scale, Meta-analysis was completed using Stata 16.0 software. Results: A total of 2 340 related literatures were searched, and 10 literatures were finally included, including 5 case-control studies and 5 indirect cohort studies, which showed good literature quality. The vaccine effectiveness against serotype 19A IPD of PCV13 in children was 83.91% (95%CI: 78.92%-88.89%), and the subgroup analysis (P=0.240) showed there was no significant difference among the case-control study (VE=87.34%, 95%CI:79.74%-94.94%) and the indirect cohort study (VE=81.30%, 95%CI:74.69%-87.92%). The funnel plot and Egger test suggested that the possibility of publication bias was small. Conclusion: The present evidence indicates that PCV13 has a good vaccine effectiveness against serotype 19A IPD in children, and it is recommended to further increase the vaccination rate of PCV13 to reduce the disease burden of IPD in children <5 years old.

Evaluating clinical effectiveness and safety of pneumococcal immunization of infants

According to WHO, pneumococcal infection (PI) is considered one of the most dangerous of all vaccine-preventable diseases and, before vaccination, led to the death of up to 1.6 million people per year, of which from 0.7 to 1 million were children. In the prevention of PI, specific prevention occupies a special place. For the first time in 2014, vaccination against PI with pneumococcal conjugate vaccine was included in the national calendar of preventive vaccinations. International practice of using pneumococcal vaccine has shown that timely vaccination can produce positive results in the fight against PI. Under observation were 55 children who were vaccinated against PI with the pneumococcal polysaccharide conjugate vaccine (adsorbed), 13 valent according to the national calendar of preventive vaccinations of the Russian Federation. It was revealed that post-vaccination complications after vaccination did not occur in any child. General post-vaccination reactions were observed in the form of a short-term increase in temperature, loss of appetite and sleep disturbances, as well as local reactions in the form of edema, hyperemia, and hardening at the site of vaccine administration. We studied the incidence of community-acquired pneumonia (CAP), acute otitis media and acute respiratory infections among 55 children of the first year of life vaccinated at 2 months and 4.5 months (main group) and 50 children for various reasons not vaccinated against PI (comparison group). A study of the long-term results of 2-fold vaccination in the first year of life and revaccination at 15 months against PV based on observation of children for two years showed that children of the main group, compared with the comparison group, were 3.3 times less likely to suffer from PV, 2.7 times acute otitis and 1.7 times acute respiratory infections, p &lt; 0.05. The data obtained show the high efficiency and safety of vaccinating children against PI with the pneumococcal vaccine.

Prognoses of patients undergoing hemodialysis administered 23-valent pneumococcal polysaccharide versus 13-valent pneumococcal protein conjugate vaccines

IntroductionSequential vaccination with the 13-valent pneumococcal protein conjugate vaccine (PCV13) and 23-valent pneumococcal polysaccharide vaccine (PPSV23) is recommended for patients undergoing hemodialysis; however, evidence for the efficacy of these pneumococcal vaccines for patients undergoing hemodialysis is limited to a single dose. We aimed to evaluate the prognosis of patients undergoing hemodialysis who received vaccination with PPSV23 alone versus sequential vaccination with PCV13 and PPSV23. MethodsPatients undergoing hemodialysis who were vaccinated with PPSV23 alone (PPSV23 group) or PCV13 followed by PPSV23 (PCV13+PPSV23 group) between 2014 and 2016 were included; the observation period was three years from the first injection. Patients who underwent hemodialysis between 2011 and 2012 were included as controls. After propensity score matching using age, sex, dialysis vintage, diabetes history, pneumonia history, and serum albumin and creatinine levels, survival analysis was performed. ResultsThe study included 89, 71, and 319 patients in the PPSV23, PCV13+PPSV23, and control groups, respectively. After propensity score matching, the PPSV23 and control group 1 (79 patients each) and the PCV13+PPSV23 and control group 2 (61 patients each) were compared. Significant differences were observed in the survival rate between the PPSV23 group and control group 1 (p = 0.005) but not between the PCV13+PPSV23 group and control group 2. Pneumonia-related mortality in the two vaccinated groups did not differ significantly during the observation period. ConclusionsPatients who received PPSV23 had a favorable prognosis; however, no positive effect was demonstrated in the PCV13+PPSV23 group.

Analysis of 13-valent pneumococcal polysaccharide conjugate vaccine among children born in Hangzhou from 2017 to 2021.

13-valent pneumococcal polysaccharide conjugate vaccine (PCV13) has been introduced in Hangzhou since 2017, whereas its current immunization state in children is not clear. Therefore, this study aims to describe the PCV13 vaccination distribution among children born in Hangzhou from 2017 to 2021 to provide data for reducing vaccination differences among different populations. Descriptive epidemiology was used for data analysis and PCV13 vaccination related information of children was collected from children vaccination management system of Zhejiang Province (ZJCVMS). Among the 649,949 children born in Hangzhou from 2017 to 2021, 169,230 were vaccinated with an average full course vaccination rate of 26.0%. The full course vaccination rates in 5 years were different (P = 0.000) with an increasing trend (P fortrend < 0.01). The first dose vaccination rates were different in 5 years (P = 0.000) with an increasing trend (P fortrend < 0.01). The distribution of age when first dose PCV13 was administered varied, most people at 2 months and least people at 5 months. The full course vaccination rate varied by areas, highest in central urban areas and lowest in remote areas respectively (all P-value < 0.05). Overall, the full course vaccination rate of PCV13 was higher in the registered residence population than the non-registered residence population, which was 136,693 (31.4%) and 32,537 (15.1%) respectively (P = 0.000). The full course vaccination rates were the same between men and women (P = 0.502), which was 87,844 for men (26.0%) and 81,386 for women (26.1%). Although the number of people who received PCV13 full course vaccination and received the first dose vaccination showed yearly increasing trends in Hangzhou, the full course vaccination rate for the whole population was relatively low. In addition, the PCV13 vaccination rates also differed by geography and household registration status. Measures such as expanding vaccination publicity or including national immunization should be taken to increase vaccination rates and reduce the differences in vaccination among groups with different characteristics.

30-Minute Highly Multiplexed VaxArray Immunoassay for Pneumococcal Vaccine Antigen Characterization.

Pneumonia accounts for over 20% of deaths worldwide in children aged 1 to 5 years, disproportionately affecting lower- and middle-income countries. Effective, highly multivalent pneumococcal vaccines are available to decrease disease burden, with numerous new vaccines currently under development to serve a variety of worldwide markets. However, pneumococcal conjugate vaccines are among the hardest biologics to manufacture and characterize due to their complexity and heterogeneity. Current characterization methods are often inherently singleplex, requiring separate tests for each serotype present. In addition, identity and quantity are often determined with separate methods. We developed the VaxArray pneumococcal assay for applications in identity, quantity, and stability testing of pneumococcal polysaccharide and pneumococcal conjugate vaccines. The VaxArray pneumococcal assay has a time to result of less than 30 min and is an off-the-shelf multiplexed, microarray-based immunoassay kit that can identify and simultaneously quantify 23 pneumococcal polysaccharide serotypes common to many on-market and in-development vaccines. Here, we highlight the potential of the assay for identity testing by showing high reactivity and serotype specificity to a wide variety of native polysaccharides, CRM197-conjugated polysaccharides, and drug product. The assay also has vaccine-relevant lower limits of quantification in the low-to-mid ng/mL range and can be used for accurate quantification even in adjuvanted vaccines. Excellent correlation to the anthrone assay is demonstrated, with VaxArray resulting in significantly improved precision over this antiquated chemical method.

The surveillance analysis of the adverse events following immunization of the domestic 13-valent pneumococcal polysaccharide conjugate vaccine in Zhejiang Province

To evaluate the safety of the domestic 13-valent pneumococcal polysaccharide conjugate vaccine-tetanus toxoid protein (PCV13-TT) after its licensure. The adverse event following immunization (AEFI) and the vaccination data of PCV13-TT in Zhejiang province from July 2020 to October 2021 were collected from national adverse event following immunization surveillance system and Zhejiang provincial immunization information system. Descriptive epidemiological method was used for this analysis. From July 2020 to October 2021, 302 317 doses of PCV13-TT were administered in children under 6 years old in Zhejiang Province and 636 AEFI case reports were received, with a reporting rate of 21.04 per 10 000 doses. Of these AEFI cases, 97.17% were mild vaccine product-related reaction (20.54 per 10 000 doses) and 95.44% occurred in the 0-1 d after vaccination (20.08 per 10 000 doses). The most common clinical diagnoses of AEFI included fever (224 cases), redness (204 cases), and induration (190 cases), while allergic rash (11 cases) was the most common diagnosis among the abnormal reactions. In conclusion,the present results bolstered that the domestic PCV13-TT was generally well tolerated in children under 6 years old in Zhejiang Province.

Streptococcus pneumoniae serotype 15B polysaccharide conjugate elicits a cross-functional immune response against serotype 15C but not 15A

Protection conferred by pneumococcal polysaccharide conjugate vaccines (PCVs) is associated with PCV-induced antibodies against vaccine-covered serotypes that exhibit functional opsonophagocytic activity (OPA). Structural similarity between capsular polysaccharides of closely related serotypes may result in induction of cross-reactive antibodies with or without a cross-functional activity against a serotype not covered by a PCV, with the former providing an additional protective clinical benefit. Serotypes 15B, 15A, and 15C, in the serogroup 15, are among the most prevalent Streptococcus pneumoniae serotypes associated with invasive pneumococcal disease following the implementation of a 13-valent PCV; in addition, 15B contributes significantly to acute otitis media. Serological discrimination between closely related serotypes such as 15B and 15C is complicated; here, we implemented an algorithm to quickly differentiate 15B from its closely related serotypes 15C and 15A directly from whole-genome sequencing data. In addition, molecular dynamics simulations of serotypes 15A, 15B, and 15C polysaccharides demonstrated that while 15B and 15C polysaccharides assume rigid branched conformation, 15A polysaccharide assumes a flexible linear conformation. A serotype 15B conjugate, included in a 20-valent PCV (PCV20), induced cross-functional OPA serum antibody responses against the structurally similar serotype 15C but not against serotype 15A, both not included in PCV20. In PCV20-vaccinated adults (18–49 years), robust OPA antibody titers were detected against both serotypes 15B (the geometric mean titer [GMT] of 19,334) and 15C (GMTs of 1692 and 2747 for strains PFE344340 and PFE1160, respectively), but were negligible against serotype 15A (GMTs of 10 and 30 for strains PFE593551 and PFE647449, respectively). Cross-functional 15B/C responses were also confirmed using sera from a larger group of older adults (60–64 years).

Conjugate of structurally reassigned pneumococcal serotype 31 polysaccharide with CRM197 elicited potent immune response

Around 100 Streptococcus pneumonia (Spn) serotypes have been discovered, 90% of the severe diseases in children are caused by 13 serotypes. With the success of pneumococcal bacterial polysaccharide conjugate vaccines (PCVs), the burden of pneumococcal disease has been significantly reduced. Serotype 31 is a non-vaccine serotype and has increased in prevalence. By using Nuclear Magnetic Resonance (NMR) as the primary tool, we report the revised serotype 31 polysaccharide (s-31-ps) structure as [→3)-β-D-Galf-(5/6-OAc)-(1 → 3)-β-D-Galp-(1 → 3)-β-L-Rhap-(2-OAc)-(1 → 2)-α-L-Rhap-(1 → 4)-β-D-GlcpA-(1→]n. Furthermore, the reductive amination-conjugate of serotype 31 polysaccharide and cross reacting material (CRM197) protein was prepared in organic solvent (N,N-dimethylformamide, DMF) instead of water. The reaction is faster, and the DMF conjugate elicited comparable immune responses with the aqueous conjugate. S-31-ps conjugate vaccine has the potential of being included in the next-generation PCV vaccines.

Isolation and Characterization of Human Monoclonal Antibodies to Pneumococcal Capsular Polysaccharide 3.

ABSTRACTThe current pneumococcal capsular polysaccharide (PPS) conjugate vaccine (PCV13) is less effective against Streptococcus pneumoniae serotype 3 (ST3), which remains a major cause of pneumococcal disease and mortality. Therefore, dissecting structure-function relationships of human ST3 pneumococcal capsular polysaccharide (PPS3) antibodies may reveal characteristics of protective antibodies. Using flow cytometry, we isolated PPS3-binding memory B cells from pneumococcal vaccine recipients and generated seven PPS3-specific human monoclonal antibodies (humAbs). Five humAbs displayed ST3 opsonophagocytic activity, four induced ST3 agglutination in vitro, and four mediated both activities. Two humAbs, namely, C10 and C27, that used the same variable heavy (VH) and light (VL) chain domains (VH3-9*01/VL2-14*03) both altered ST3 gene expression in vitro; however, C10 had fewer VL somatic mutations, higher PPS3 affinity, and promoted in vitro ST3 opsonophagocytic and agglutinating activity, whereas C27 did not. In C57BL/6 mice, both humAbs reduced nasopharyngeal colonization with ST3 A66 and a clinical strain, B2, and prolonged survival following lethal A66 intraperitoneal infection, but only C10 protected against lethal intranasal infection with the clinical strain. After performing VL swaps, C10VH/C27VL exhibited reduced ST3 binding and agglutination, but C27VH/C10VL binding was unchanged. However, both humAbs lost the ability to reduce colonization in vivo when their light chains were replaced. Our findings associate the ability of PPS3-specific humAbs to reduce colonization with ST3 agglutination and opsonophagocytic activity, and reveal an unexpected role for the VL in their functional activity in vitro and in vivo. These findings also provide insights that may inform antibody-based therapy and identification of surrogates of vaccine efficacy against ST3.IMPORTANCE Despite the global success of vaccination with pneumococcal conjugate vaccines, serotype 3 (ST3) pneumococcus remains a leading cause of morbidity and mortality. In comparison to other vaccine-included serotypes, the ST3 pneumococcal capsular polysaccharide (PPS3) induces a weaker opsonophagocytic response, which is considered a correlate of vaccine efficacy. Previous studies of mouse PPS3 monoclonal antibodies identified ST3 agglutination as a correlate of reduced ST3 nasopharyngeal colonization in mice; however, neither the agglutinating ability of human vaccine-elicited PPS3 antibodies nor their ability to prevent experimental murine nasopharyngeal colonization has been studied. We generated and analyzed the functional and in vivo efficacy of human vaccine-elicited PPS3 monoclonal antibodies and found that ST3 agglutination associated with antibody affinity, protection in vivo, and limited somatic mutations in the light chain variable region. These findings provide new insights that may inform the development of antibody-based therapies and next-generation vaccines for ST3.

16. A Randomized Phase 1 Study of a Novel Pneumococcal Conjugate Vaccine in Healthy Japanese Adults in the United States

BackgroundBecause of the number and variability of serotypes causing pneumococcal disease among different geographic regions, age groups, and environmental backgrounds, expanding serotype coverage with pneumococcal conjugate vaccines (PCVs) is a continued unmet need.MethodsThis phase 1, randomized, double-blind study included healthy Japanese adults aged 18–49 years residing in the United States. Subjects were randomized 1:1:1 to receive a single dose of a 20-valent PCV (containing 13-valent PCV [PCV13] serotypes plus 8, 10A, 11A, 12F, 15B, 22F, 33F), a novel pneumococcal polysaccharide conjugate vaccine with extended coverage, or PCV13 (control). Safety was the primary endpoint and included reactogenicity events occurring ≤ 14 days after vaccination, adverse events (AEs) ≤ 1 month after vaccination, and serious AEs (SAEs) ≤ 6 months after vaccination. The secondary endpoint was pneumococcal serotype-specific immunogenicity as determined by opsonophagocytic activity (OPA) titers on sera collected before and 1 month after vaccination.ResultsOverall, 35 subjects received PCV20 and 35 subjects received PCV13. One subject withdrew before the 1-month follow-up. Local reactions and systemic events across groups were generally mild or moderate (Figure 1). Two vaccine-related AEs occurred (injection site erythema and swelling in the PCV20 group); no severe AEs, SAEs, or safety-related withdrawals were reported. OPA geometric mean titers increased for all 20 serotypes in the PCV20 group and all 13 serotypes in the PCV13 group 1 month after vaccination; corresponding OPA geometric mean fold rises from baseline to 1 month after vaccination are reported (Figure 2; Figure 3).Figure 1 Figure 2 Figure 3 ConclusionPCV20 was well tolerated and induced serotype-specific functional OPA immune responses that are anticipated to be associated with protection in Japanese adults. ClinicalTrials.gov: NCT03642847. Funding: Pfizer Inc.DisclosuresDavid Fitz-Patrick, MD, Pfizer Inc (Grant/Research Support) Mariano Young Jr., MD, Pfizer Inc (Employee, Shareholder) Daniel Scott, MD, Pfizer (Employee, Shareholder) Ingrid L. Scully, PhD, Pfizer Inc (Employee, Shareholder) Gary Baugher, PharmD, Pfizer Inc (Employee, Shareholder) Yahong Peng, PhD, Pfizer (Employee, Shareholder) Kathrin U. Jansen, PhD, Pfizer (Employee, Shareholder) William C. Gruber, MD, Pfizer (Employee, Shareholder) Wendy Watson, MD, Pfizer (Employee, Shareholder)

Divergent serotype replacement trends and increasing diversity in pneumococcal disease in high income settings reduce the benefit of expanding vaccine valency

Streptococcus pneumoniae is a significant cause of otitis media, pneumonia, and meningitis. Only seven of the approximately 100 serotypes were initially included in the pneumococcal polysaccharide conjugate vaccine (PCV) in 2000 before it was expanded in subsequent years. Although the invasive pneumococcal disease (IPD) incidence due to vaccine serotypes (VT) has declined, partial replacement by non-vaccine serotypes (NVT) was observed following widespread vaccine uptake. We conducted a trend analysis assembling the available evidence for PCV impact on European, North American and Australian national IPD. Significant effectiveness against VT IPD in infants was observed, although the impact on national IPD incidence varied internationally due to serotype replacement. Currently, NVT serotypes 8, 9N, 15A and 23B are increasing in the countries assessed, although a variety of other NVTs are affecting each country and age group. Despite these common emerging serotypes, there has not been a dominant IPD serotype post-vaccination as there was pre-vaccination (serotype 14) or post-PCV7 (serotype 19A), suggesting that future vaccines with additional serotypes will be less effective at targeting and reducing IPD in global populations than previous PCVs. The rise of diverse NVTs in all settings’ top-ranked IPD-causing serotypes emphasizes the urgent need for surveillance data on serotype distribution and serotype-specific invasiveness post-vaccination to facilitate decision making concerning both expanding current vaccination programmes and increasing vaccine valency.

Efficacy of Pneumococcal Polysaccharide Conjugate Vaccine (13-valent, Adsorbed) in Patients with Systemic Juvenile Idiopathic Arthritis Treated with Genetically Engineered Biologic Drugs (Tocilizumab or Canakinumab): Prospective Cohort Study

Background. Immunological potency of 13-valent pneumococcal vaccine (PCV-13) in children with systemic juvenile idiopathic arthritis (SJIA) is still unstudied. Estimates of the genetically engineered biologic drugs (GEBD) effects on pneumococcal vaccination results also remain controversial.Objective. The aim of the study was to explore the PCV-13 efficacy in patients with SJIA and who is on treatment with monoclonal antibodies against interleukin 6 receptor (tocilizumab) and interleukin 8 receptor beta (canakinumab).Methods. The study included patients under the age of 18 with SJIA in remission or active form of disease vaccinated with PCV-13. The vaccine was administered in single dose of 0.5 ml intramuscularly in patients on treatment with GEBD or 3 weeks before GEBD administration for the first time (for patients with active disease). Vaccination was considered effective at achievement of the minimum protective level of antibodies to capsular polysaccharide of pneumococcus (anti-SPP IgG; ≥ 7 U/ml) or increase of anti-SPP IgG level ≥ 2 times in 4 weeks after vaccination. The anti-SPP IgG levels were measured with enzyme immunoassay.Results. The study included 53 patients (27 girls) in remission of SJIA and 25 (16 girls) in active disease. Median age was 13.3 and 10.8 years respectively. Tocilizumab/canakinumab was administrated in 43/10 and 18/7 patients respectively. Minimum significant anti-SPP IgG level and two-fold increase in anti-SPP IgG level were recorded in 49/53 (92%) and 32/53 (60%) patients with SJIA in remission, as well as in 22/25 (88%) and 18/25 (72%) patients in active disease respectively. PCV-13 immunological potency in patients with SJIA in remission and in active disease (in those who were initially administrated and who did not receive GEBD) did not differ.Conclusion. PCV-13 vaccination allows to achieve protective antibodies level in most of the patients with SJIA in children population regardless of the disease stage and the history of GEBD administration.

Lipidation of Pneumococcal Antigens Leads to Improved Immunogenicity and Protection.

Streptococcus pneumoniae infections lead to high morbidity and mortality rates worldwide. Pneumococcal polysaccharide conjugate vaccines significantly reduce the burden of disease but have a limited range of protection, which encourages the development of a broadly protective protein-based alternative. We and others have shown that immunization with pneumococcal lipoproteins that lack the lipid anchor protects against colonization. Since immunity against S. pneumoniae is mediated through Toll-like receptor 2 signaling induced by lipidated proteins, we investigated the effects of a lipid modification on the induced immune responses in either intranasally or subcutaneously vaccinated mice. Here, we demonstrate that lipidation of recombinant lipoproteins DacB and PnrA strongly improves their immunogenicity. Mice immunized with lipidated proteins showed enhanced antibody concentrations and different induction kinetics. The induced humoral immune response was modulated by lipidation, indicated by increased IgG2/IgG1 subclass ratios related to Th1-type immunity. In a mouse model of colonization, immunization with lipidated antigens led to a moderate but consistent reduction of pneumococcal colonization as compared to the non-lipidated proteins, indicating that protein lipidation can improve the protective capacity of the coupled antigen. Thus, protein lipidation represents a promising approach for the development of a serotype-independent pneumococcal vaccine.

Human medicines European public assessment report (EPAR): Prevenar 13, pneumococcal polysaccharide conjugate vaccine (13-valent, adsorbed), Pneumococcal Infections,Immunization, Date of authorisation: 09/12/2009, Revision: 34, Status: Authorised

Human medicines European public assessment report (EPAR): Prevenar 13, pneumococcal polysaccharide conjugate vaccine (13-valent, adsorbed), Pneumococcal Infections,Immunization, Date of authorisation: 09/12/2009, Revision: 34, Status: Authorised

Pneumococcal vaccination coverages by age, sex and specific underlying risk conditions among middle-aged and older adults in Catalonia, Spain, 2017.

BackgroundRecent published data on pneumococcal vaccination coverages among adults are scarce.AimTo update on pneumococcal vaccination uptakes among middle-aged and older adults in Catalonia.MethodsWe conducted a population-based retrospective observational study including 2,057,656 individuals ≥ 50 years old assigned to primary care centres managed by the Catalonian Health Institute on 1 January 2017 (date of data collection). An institutional clinical research database (SIDIAP) was used to classify persons by vaccination status for both 23-valent pneumococcal polysaccharide (PPsV23) and 13-valent pneumococcal conjugate (PCV13) vaccines, as well as to identify underlying risk conditions.ResultsOverall, 796,879 individuals (38.7%) had received PPsV23 and 13,607 (0.7%) PCV13. PPsV23 coverage increased with age: 9.2% (95,409/1,039,872) in 50–64 year olds, 63.1% (434,408/688,786) in 65–79 year olds and 81.2% (267,062/328,998) in ≥ 80 year olds (p < 0.001). PCV13 coverage also increased with age, although percentages were smaller in all age strata (4,250/1,039,872: 0.4%; 6,005/688,786: 0.9% and 3,352/328,998: 1.0%, respectively; p < 0.001). By sex, no substantial coverage differences were observed. Considering publically funded target groups for PPsV23 vaccination in Catalonia (i.e. < 65 year olds with at least one risk factor, plus all adults aged ≥ 65 years), PPsV23 coverage reached 52.8% (771,722/1,462,261) in our study population. Regarding PCV13 publicly funded targets (i.e. all-age immunocompromised persons), PCV13 coverage was 3.3% (6,617/202,348). By risk conditions, the highest PPsV23 coverage appeared in congestive heart failure (51,909/63,596; 81.6%), chronic renal disease (122,791/158,726; 77.4%) and chronic bronchitis/emphysema (96,453/132,306; 72.9%). Maximum PCV13 coverage appeared in cirrhosis (294/7,957; 3.7%), chronic renal disease (5,633/158,726; 3.5%) and chronic bronchitis/emphysema (2,859/132,306; 2.2%).ConclusionPneumococcal vaccination coverages in Catalonian adults are suboptimal, especially for PCV13.

Assignment of Serotype-Specific IgG1, IgG2, and IgA Weight-Based Antibody Units to the Human Pneumococcal Standard Reference Serum, 007sp.

In 2011, the human pneumococcal standard reference serum, 007sp, was established as a replacement for the previous standard, lot 89SF, supplies of which were dwindling. The pneumococcal reference serum is used primarily in the standardized pneumococcal enzyme-linked immunosorbent assay (World Health Organization reference enzyme-linked immunosorbent assay) but has also been used in functional assays. Serotype-specific IgG values for 24 pneumococcal capsular serotypes have previously been assigned to 007sp by bridging to the original values derived for lot 89SF. In this study, by bridging to existing values in lot 89SF, we assign weight-based serotype-specific IgA, IgG1, and IgG2 to 007sp for 11 pneumococcal capsular serotypes (1, 3, 4, 5, 6B, 7F, 9V, 14, 18C, 19F, and 23F), as well as serotype 19A-specific IgA. Concentrations for serotype-specific IgA, IgG1, and IgG2 present in 007sp were comparable to those previously assigned to lot 89SF. In addition, the concentration of serotype-specific IgG1 plus IgG2 assigned to 007sp significantly correlated to previously assigned 007sp IgG values. The accuracy of antibody assignments to 007sp from lot 89SF was assessed by comparing the concentration of serotype-specific IgA, IgG1, and IgG2 in 16 unknown samples using both 007sp and lot 89SF as the standard. Interpolated values for the unknown samples were highly correlated with average R2 values of 0.9729, 0.9951, and 0.9933 for IgA, IgG1, and IgG2, respectively, for all serotypes demonstrating the precise nature assignments to 007sp made in this study. Nonparallelism between 007sp and lot 89SF has precluded the derivation of serotype-specific IgM values.IMPORTANCE A well-characterized antibody standard is an indispensable reagent for use in assays designed to measure antibodies with precision and where assays between laboratories need to be comparable. The human pneumococcal standard reference serum, lot 89SF, greatly facilitated the standardization of enzyme-linked immunosorbent assay methodologies during a critical period when the first pneumococcal polysaccharide-conjugate vaccines were being evaluated for licensure. Due to dwindling supplies of lot 89SF, a new reference standard, 007sp, was produced in 2011. Understanding the isotype and subclass composition of either natural or vaccine induced responses to pathogens has assumed increasing importance. In this study, we have assigned IgA, IgG1, and IgG2 values to pneumococcal serotypes 1, 3, 4, 5, 6B, 7F, 9V, 14, 18C, 19A, 19F, and 23F by bridging to existing values in lot 89SF.

Human medicines European public assessment report (EPAR): Prevenar 13, pneumococcal polysaccharide conjugate vaccine (13-valent, adsorbed), Pneumococcal Infections,Immunization, Date of authorisation: 09/12/2009, Revision: 33, Status: Authorised

Human medicines European public assessment report (EPAR): Prevenar 13, pneumococcal polysaccharide conjugate vaccine (13-valent, adsorbed), Pneumococcal Infections,Immunization, Date of authorisation: 09/12/2009, Revision: 33, Status: Authorised

Human monoclonal antibodies isolated from a primary pneumococcal conjugate Vaccinee demonstrates the expansion of an antigen-driven Hypermutated memory B cell response

BackgroundCommunity-acquired pneumonia is a leading infectious cause of hospitalization. A few vaccines exist to prevent pneumococcal disease in adults, including a pneumococcal polysaccharide unconjugated vaccine and a protein conjugated polysaccharide vaccine. Previous studies on the human immune response to the unconjugated vaccine showed that the vaccine boosted the existing memory B cells. In the present study, we investigated the human B cell immune response following pneumococcal polysaccharide conjugate vaccination.MethodsPlasmablast B cells from a pneumococcal polysaccharide conjugate vaccinee were isolated and cloned for analysis. In response to primary vaccination, identical sequences from the plasmablast-derived antibodies were identified from multiple B cells, demonstrating evidence of clonal expansion. We evaluated the binding specificity of these human monoclonal antibodies in immunoassays, and tested there in vitro function in a multiplexed opsonophagocytic assay (MOPA). To characterize the plasmablast B cell response to the pneumococcal conjugated vaccine, the germline usage and the variable region somatic hypermutations on these antibodies were analyzed. Furthermore, a serotype 4 polysaccharide-specific antibody was tested in an animal challenge study to explore the in vivo functional activity.ResultsThe data suggests that the pneumococcal polysaccharide conjugate vaccine boosted memory B cell responses, likely derived from previous pneumococcal exposure. The majority of the plasmablast-derived antibodies contained higher numbers of variable region somatic hypermutations and evidence for selection, as demonstrated by replacement to silent ratio’s (R/S) greater than 2.9 in the complementarity-determining regions (CDRs). In addition, we found that VH3/JH4 was the predominant germline sequence used in these polysaccharide-specific B cells. All of the tested antibodies demonstrated narrow polysaccharide specificity in ELISA binding, and demonstrated functional opsonophagocytic killing (OPK) activity in the MOPA assay. The in-vivo animal challenge study showed that the tested serotype 4 polysaccharide-specific antibody demonstrated a potent protective effect when administered prior to bacterial challenge.ConclusionsThe findings on the pneumococcal polysaccharide conjugate vaccine responses from a vaccinated subject reported in this study are similar to previously published data on the pneumococcal polysaccharide unconjugated vaccine responses. In both vaccine regimens, the pre-existing human memory B cells were expanded after vaccination with preferential use of the germline VH3/JH4 genes.