Incremental effectiveness of 23-valent pneumococcal polysaccharide vaccine against pneumonia hospitalisation among Australian Indigenous children: A record linkage study

BACKGROUND

The impact of pneumococcal conjugate vaccines (PCVs) on pneumonia in children is well-documented but data on 23-valent pneumococcal polysaccharide vaccine (PPV23) are lacking. Between 2001 and 2011, Indigenous children in Western Australia (WA) were recommended to receive PPV23 at 18-24 months of age following 3 doses of 7-valent PCV. We evaluated the incremental effectiveness of PPV23 against pneumonia hospitalisation.

METHODS

Indigenous children born in WA between 2001 and 2012 who received PCV dose 3 by 12 months of age were followed from 18 to 60 months of age for the first episode of pneumonia hospitalisation (all-cause and 3 subgroups: presumptive pneumococcal, other specified causes, and unspecified). We used Cox regression modelling to estimate hazard ratios (HRs) for pneumonia hospitalisation among children who had, versus had not, received PPV23 between 18 and 30 months of age after adjustment for confounders.

RESULTS

11,120 children had 327 first episodes of all-cause pneumonia hospitalisation, with 15 (4.6%) coded as presumptive pneumococcal, 46 (14.1%) as other specified causes and 266 (81.3%) unspecified. No statistically significant reduction in all-cause pneumonia was seen with PPV23 (HR 1.11; 95% CI: 0.87-1.43), but the direction of the association differed for presumptive pneumococcal (HR 0.47; 95% CI: 0.16-1.35) and specified (HR 0.89; 95% CI: 0.49-1.62) from unspecified causes (HR 1.13; 95% CI: 0.86-1.49). During the baseline period before PPV23 vaccination (12-18 months), all-cause pneumonia risk was higher among PPV23-vaccinated than unvaccinated children (RR: 1.73; 95% CI: 1.30-2.28).

CONCLUSION

In this high-risk population, no statistically significant incremental effect of a PPV23 booster at 18-30 months was observed against hospitalised all-cause pneumonia or the more specific outcome of presumptive pneumococcal pneumonia. Confounding by indication may explain the slight trend towards an increased risk against all-cause pneumonia. Larger studies with better control of confounding are needed to further inform PPV23 vaccination.

Evaluating clinical effectiveness and impact of anti-pneumococcal vaccination in adults after universal childhood PCV13 implementation in Catalonia, 2017-2018

Background

At present, because of indirect effects derived from routine childhood immunisation, clinical benefits vaccinating adults with the 23-valent pneumococcal polysaccharide vaccine (PPsV23) and/or the 13-valent pneumococcal conjugate vaccine (PCV13) are uncertain. This study investigated clinical effectiveness for both PPsV23/PCV13 in preventing pneumonia among Catalonian adults during an earlier 2-year period post-PCV13 free (publicly funded) approval for infants.

Methods

We conducted a Population-based cohort study involving 2,059,645 adults ≥ 50 years in Catalonia, Spain, who were followed between 01/01/2017-31/12/2018. Primary outcomes were hospitalisation from pneumococcal pneumonia (PP) or all-cause pneumonia (ACP) and main explanatory variable was PCV13/PPsV23 vaccination status. Cox regression models were used to estimate vaccination effectiveness adjusted by age/sex and underlying-risk conditions.

Results

Cohort members were followed for 3,958,528 person-years (32,328 PCV13-vaccinated, 1,532,186 PPsV23-vaccinated), observing 3592 PP (131 in PCV13-vaccinated vs 2476 in PPsV23-vaccinated) and 24,136 ACP (876 in PCV13-vaccinated vs 17,550 in PPsV23-vaccinated). Incidence rates (per 100,000 person-years) were 90.7 for PP (394.2 in PCV13-vaccinated vs 161.6 in PPsV23-vaccinated) and 609.7 for ACP (2636.3 in PCV13-vaccinated vs 1145.4 in PPsV23-vaccinated). The PCV13 was associated with an increased risk of PP (hazard ratio [HR]: 1.24; 95% CI: 1.00-1.52; p = 0.046) and ACP (HR: 1.38; 95% CI: 1.28-1.49; p < 0.001) whereas the PPsV23 did not alter the risk of PP (HR: 1.07; 95% CI: 0.98-1.18; p = 0.153) and slightly increased the risk of ACP (HR: 1.14; 95% CI: 1.10-1.18; p < 0.001). In supplementary analyses focused on at-risk individuals (i.e., elderly persons, immunocompromissing and other chronic illnesses) protective effects of vaccination did not emerge either.

Conclusions

Data does not support clinical benefits from pneumococcal vaccination (nor PCV13 neither PPsV23) against pneumonia among Catalonian middle-aged and older adults in the current era of universal PCV13 childhood immunisation in our setting. New extended valency PCVs are greatly needed.

Application of vaccine response in the evaluation of patients with suspected B-cell immunodeficiency: Assessment of responses and challenges with interpretation

Diagnostic vaccination is an integral component in the evaluation of patients suspected to have a B cell or humoral deficiency. Evaluation of antibody production in response to both protein- and polysaccharide-based vaccines aids in distinguishing between specific categories of humoral deficiency. Although assessment of pneumococcal polysaccharide responses is widely available and included in diagnostic guidelines, significant variability still exists in the measurement and interpretation of these responses. Interpretation can also be complicated by age, vaccination history and treatment with immunoglobulin replacement therapy. Despite the challenges and limitations of evaluating pneumococcal polysaccharide vaccine responses, it can provide valuable diagnostic and prognostic information to guide therapeutic intervention. Future efforts are needed to further standardize measurement and interpretation of pneumococcal antibody responses to vaccination and to identify and establish other methods and/or vaccines as alternatives to pneumococcal vaccination to address the challenges in certain patient populations.

Effectiveness of the 23-valent pneumococcal polysaccharide vaccine against invasive pneumococcal disease among 948,263 individuals ≥ 65 years of age: a Danish cohort study

This study aimed to estimate the effectiveness of the 23-valent pneumococcal polysaccharide vaccine (PPV23) against invasive pneumococcal disease (IPD) among individuals ≥ 65 years of age. We used Danish nationwide databases to obtain information on PPV23 vaccination, covariates, and IPD and linked data on an individual level using a unique personal identifier. A total of 948,263 individuals were included and followed between June 15, 2020, and September 18, 2021 (58.6% were vaccinated during follow-up). The adjusted vaccine effectiveness was 42% (95% confidence interval (CI): 9–63%) for all-serotype IPD and 58% (95% CI: 21–78%) for PPV23-serotype IPD, using no vaccination as the reference.

Immunogenicity and safety of double dosage of pneumococcal vaccines in adult kidney transplant recipients and waiting list patients: A non-blinded, randomized clinical trial

BACKGROUND

Pneumococcal prime-boost vaccination is recommended for solid organ transplant recipients, but is not thoroughly tested in this population. Furthermore, a pneumococcal vaccine dose effect has never been investigated, though observed in healthy adults. To assess whether a double dose of 13-valent pneumococcal conjugate vaccine (PCV13) and of 23-valent pneumococcal polysaccharide vaccine (PPV23) increases the immunogenicity of prime-boost vaccination in kidney transplant recipients (KTRs) and patients on the kidney transplant waiting list (WLPs), a phase 3, randomized, non-blinded trial was conducted.

METHODS

KTRs and WLPs were in parallel groups assigned either normal or double dosage of both vaccines 12 weeks apart. A 'protective response' was an average geometric mean concentration ≥ 1 mg/L based on 12 vaccine shared serotype-specific IgG antibodies. Furthermore, number of antibodies with ≥ 2-fold rises and individual serotype-specific antibody concentrations were evaluated. Follow-up was 48 weeks.

RESULTS

Seventy-four KTRs and 65 WLPs were enrolled. In WLPs, double dosage resulted in a significantly higher proportion of participants with a 'protective response' (66.7%), 5 weeks after PPV23, compared to normal dosage (35.5%), p = 0.015. KTRs exhibited no dose effect. After PPV23, all four groups had increased their number of serotypes with ≥ 2-fold rises (p ≤ 0.05 for both WLPs groups; p ≤ 0.01 for both KTRs groups). Vaccines were safe, well tolerated and still immunogenic at week 48.

CONCLUSIONS

Data suggests that double dosage of pneumococcal vaccines used according to the prime-boost strategy might be recommendable for WLPs. Furthermore, our data supports PPV23́s additive effect to PCV13 in KTRs and WLPs. (EudraCT: 2016-004123-23).

Pneumococcal IgG Antibody Responses to 23vPPV in Healthy Controls Using an Automated ELISA

Measurement of pre- and post-pneumococcal antibody levels after immunization with the 23-valent capsular polysaccharide pneumococcal vaccine (23vPPV) is indicative of a T-independent antibody response. The World Health Organisation ELISA is considered gold standard yet is labor-intensive and technically difficult to perform. Interpretation criteria defining an adequate response to 23vPPV remain controversial. The diagnostic Immunology Laboratory at The Royal Children's Hospital, Melbourne (RCH), performs an in-house multi-serotype automated ELISA. The primary objective of this study was to verify RCH interpretation criteria for the laboratory's automated ELISA. Forty pneumococcal conjugate vaccine (PCV)-naïve healthy adults aged 18 to 25 years and 22 PCV-primed healthy children aged 2 to 5 years were immunized with 23vPPV. A serum sample was collected immediately prior and 28 to 42 (± 7) days post immunization. Samples were analyzed on the Tecan Freedom Evo 200 ELISA with adequate response defined as post-immunization antibody level of 1.3 µg/mL or fourfold rise from baseline in ≥ 10/15 serotypes in adult participants and ≥ 4/8 serotypes in pediatric participants. Thirty-nine (97.5%) adults and 22 (100%) children achieved an adequate response to 23vPPV. In PCV-naïve adults, serotypes contained within the conjugate vaccines were less immunogenic, with 12 (30%) adults not achieving an adequate antibody response when only PCV serotypes were used for interpretation. Our diagnostic laboratory has verified the interpretation criteria used for an automated multi-serotype pneumococcal ELISA method. Clinical Trial Registration: ANZCTR registration number ACTRN12618000822280.

[Vaccination against community acquired pneumonia in adults. Update 2021 of the position paper by Neumoexpertos en Prevención Group]

Community-acquired pneumonia (CAP) continues to be an important cause of morbidity and mortality in adults. The aim of this study is to update the practical prevention guide for CAP through vaccination in Spain developed in 2016 and updated in 2018, based on available vaccines and evidence through bibliographic review and expert opinion. The arrival of COVID-19 as a new cause of CAP and the recent availability of safe and effective vaccines constitutes the most significant change. Vaccines against pneumococcus, influenza, pertussis and COVID-19 can help to reduce the burden of disease from CAP and its associated complications. The available evidence supports the priority indications established in this guide, and it would be advisable to try to achieve a widespread dissemination and implementation of these recommendations in routine clinical practice.

Pneumococcal serotype-specific cut-offs based on antibody responses to pneumococcal polysaccharide vaccination in healthy adults

Antibody responses to pneumococcal polysaccharide vaccination are frequently used as a diagnostic tool for humoral immunodeficiencies, part of the larger collection of inborn errors of immunity. Currently, arbitrary criteria, such as a serotype specific titer of >/= 1.3 µg/mL is most often used as a cut-off for interpretation of pneumococcal antibody responses. The magnitude of the antibody response to each of the 23 serotypes in Pneumovax®, and serotype-specific cut-offs in healthy pneumococcal vaccine-naïve adults has not been previously characterized. IgG antibody concentrations were measured prospectively for 23 pneumococcal serotypes pre and 4-6 weeks post-Pneumovax® vaccination in 100 healthy adults, using a multiplex bead-based assay. Antibodies to 19 of 23 serotypes were informative for distinguishing subjects who responded to vaccination, and the serotype threshold was determined to be 9 of 19 serotypes, which characterized an antibody response to pneumococcal vaccination. While this study may facilitate classification of IgG serotype-specific antibody responses post-pneumococcal vaccination in adult patients undergoing diagnostic immunological evaluation for antibody immunodeficiencies or other relevant contexts, additional studies in healthy children and S. pneumoniae protein-conjugate-vaccinated healthy adults will need to be undertaken in the future.

[Evaluation of the change in pneumococcal vaccination in 2018 in adults in the Community of Madrid]

BACKGROUND

In the Community of Madrid since 2005 vaccination against pneumococcus in adults from 60 years of age has been carried out with pneumococcal polysaccharide vaccine (PPV23). In January 2018, the guideline changed in favor of pneumococcal conjugate vaccine (PCV13). The objective of this study was to analyze the data of pneumococcal vaccination and to evaluate the implementation of the new guideline of vaccination against pneumococcus in adults in the Community of Madrid.

METHODS

Cross-sectional study to estimate vaccine coverage by a retrospective review of the record of vaccination history of people ≥60 years resident in the Community of Madrid.

RESULTS

In the Community of Madrid until 2018, 83% of the population were vaccinated with PPV23, 6% with PCV13 and 11% with both vaccines. 96.5% came from Primary Care records. The doses administered of PCV13 surpassed those of PPV23 in ≥60 years in all age groups. 78,660 people ≥60 years were vaccinated with PCV13 (19.5% without risk factors, 67.3% with chronic diseases, 2.5% of the high-risk group and 10.7% belonging to both groups).

CONCLUSIONS

In 2018, following Community of Madrid recommendations, 6,639 people were not properly vaccinated with PCV13 and 72,021 (91.6%) were properly vaccinated. The greatest confusion occurred in people ≥60 years without risk factors who had a previous PPV23 and did not require another vaccine but received a PCV13 without complying with the recommended schedule.

Effectiveness of a 23-valent pneumococcal polysaccharide vaccine for the prevention of pneumococcal pneumonia in the elderly with chronic respiratory diseases: a case-control study of a single center

Background

The effectiveness of the 23-valent pneumococcal polysaccharide vaccine (PPSV23) in preventing pneumococcal pneumonia has been controversial.

Methods

To evaluate the effectiveness of the PPSV23 in elderly outpatients with chronic respiratory diseases, we carried out a case–control study, including 4128 outpatients aged ≥ 65 years, in the respiratory department.

Results

There were 320 vaccinated patients, of which 164 were diagnosed with pneumococcal pneumonia. The adjusted odds ratio was 0.39 (95% confidence interval (CI), 0.17 to 0.89). In the subsets consisting of age groups ≥ 70 and ≥ 75 years, the adjusted odds ratio (95% CI) was respectively 0.16 (0.04 to 0.67) and 0.15 (0.02 to 1.12).

Conclusion

This real-world study suggests that PPSV23 can be useful in preventing pneumococcal pneumonia in the elderly with chronic respiratory diseases.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-021-01491-w.

Immunogenicity following revaccination or sequential vaccination with 23-valent pneumococcal polysaccharide vaccine (PPSV23) in older adults and those at increased risk of pneumococcal disease: a review of the literature

Introduction: Immunogenicity studies evaluating sequential administration of pneumococcal conjugate vaccine (PCV) followed by 23-valent pneumococcal polysaccharide vaccine (PPSV23) or revaccination with PPSV23 have raised concerns that PPSV23 may not elicit higher antibody levels than those measured following PCV or first PPSV23 dose.Areas covered: Recent literature was evaluated for evidence of blunted immune response (hyporesponsiveness), focusing on studies using adequate intervals between doses in accordance with vaccination recommendations. In eight of nine studies that evaluated revaccination with PPSV23 at an interval of ≥5 years after the previous dose, immunoglobulin G geometric mean concentrations and/or opsonophagocytic assay geometric mean titers for most serotypes increased from pre- to post-repeat vaccination and were comparable between repeat and primary vaccination groups post-vaccination. In seven studies in which PPSV23 was administered after PCVs (8 weeks to 1 year apart), responses to PPSV23 were comparable to those seen after initial PCV dose for shared vaccine serotypes. Studies in which PCVs were administered after PPSV23 were not evaluated.Expert opinion: Published data suggest immune responses following repeat vaccination with PPSV23, or sequential PCV/PPSV23 vaccination, are robust, without evidence of hyporesponsiveness. PPSV23 vaccination of at-risk adults is essential to ensure broad protection against all 23 vaccine serotypes.

Pneumococcal polysaccharide vaccine is a cost saving strategy for prevention of acute coronary syndrome

OBJECTIVE

There is evidence that the pneumococcal polysaccharide vaccine (PPV) may reduce cardiovascular disease. We aimed to evaluate the cost-effectiveness of PPV for primary prevention of acute coronary syndrome (ACS) in the elderly in Australia.

METHODS

A Markov model was developed to investigate the costs, QALYs and ICERs of PPV administration in those aged ≥65 years without a history of ACS from the perspective of Australian healthcare system, using elderly-specific clinical data and local costs from Australian Heart Foundation and Australian Institute of Health and Welfare databases. A ten-years horizon was used, and all costs and health outcomes were discounted at 5% annually. The impact of various assumptions was tested with sensitivity analyses.

RESULTS

In the base-case analysis, interventional strategy (100% PPV coverage) prevented an additional five incident ACS events among 1000 "healthy" elderly individuals compared with standard of care (50% PPV coverage) over 10 years. 100% PPV was the dominant strategy, resulting in a QALY gain of 0.0075 and cost saving of AU$ 179 per person. The results were most sensitive to effectiveness of PPV at preventing ACS and reducing hospital bed-days, and cost of ACS admission, but in all sensitivity analyses 100% PPV remained the dominant strategy. Shortening the time horizon from ten to five years resulted in further cost saving.

CONCLUSION

PPV for the prevention of ACS in those aged ≥65 is a dominant intervention strategy, with cost saving and minor improvements in QALY. Healthcare providers should promote PPV administration for all eligible populations.

Estimating pneumococcal vaccine coverage among Australian Indigenous children and children with medically at-risk conditions using record linkage

BACKGROUND

Risk-based recommendations are common for pneumococcal vaccines but little is known about their uptake. In Australia, pneumococcal conjugate vaccine (PCV) was funded only for Aboriginal or Torres Strait Islander (Indigenous) children and those with underlying medical conditions in 2001, and then there were different booster dose recommendations depending on risk after the introduction of universal PCV vaccination in 2005.

METHODS

We measured coverage of PCV dose 3 and additional PCV and 23-valent pneumococcal polysaccharide vaccine (PPV23) doses by risk group among children born in July 2001-December 2012 in two Australian states using linked immunisation and hospitalisation data (available until December 2013). We ascertained medical risk conditions using hospitalisation diagnosis codes and Indigenous status using an established algorithm, comparing coverage for children born pre (2001-2004) and post (2005-2012) universal PCV funding.

RESULTS

Among 1.3 million children, 63,897 (4.9%) were Indigenous and 32,934 (2.5%) had at least one medically at-risk condition identified by age 6 months. For births in 2001-2004, coverage for PCV dose 3 by 1 year of age was 37% for Indigenous, 15% for medically at-risk and 11% in other children, increasing to 83%, 91% and 92%, respectively for births in 2005-2012. In children with medically at-risk conditions, PCV dose 4 coverage by 2 years was 1% for 2001-2004 births, increasing to 9% for 2005-2012 births, with PPV23 coverage by 6 years 3% in both cohorts. Among eligible Indigenous children, PPV23 coverage by 3 years was 45% for 2001-2004 births and 51% for 2005-2012 births.

CONCLUSIONS

Coverage with additional recommended booster doses was very low among children with medical conditions, and only modest among Indigenous children. If additional PCV doses are recommended for some risk groups, especially in the context of routine schedules with reduced doses (e.g. 2 + 1 and 1 + 1), measures to improve implementation will be required.

Response to Shami et al. 'Evaluating the cost-effectiveness of a sequential pneumococcal vaccination compared to single dose vaccination strategy for adults in Hong Kong' (Hum Vacc Immunother 2020)

The recently published article by Shami et al. describes a cost-effectiveness analysis of sequential pneumococcal vaccination with 13-valent pneumococcal conjugate vaccine (PCV13) followed by 23-valent pneumococcal polysaccharide vaccine (PPSV23), compared with a single PPSV23 dose, in adults in Hong Kong. Sequential vaccination was cost-saving versus PPSV23 alone. The model assumed vaccine effectiveness (VE) of 0% for PPSV23 against all-cause non-bacteremic pneumonia; this was based on studies with flawed methodologies and studies that did not evaluate non-bacteremic pneumococcal disease. In recent studies and meta-analyses, PPSV23 VE pneumococcal pneumonia, including against non-bacteremic pneumococcal pneumonia, ranged from 27% to 64%. In other cost-effectiveness analyses, assumptions for PPSV23 VE against non-bacteremic pneumococcal pneumonia, had dramatic effects on cost-effectiveness estimates. Future analyses must carefully consider PPSV23 VE assumptions to ensure accuracy.

[Expert consensus on immunoprophylaxis of pneumococcal disease (2020 version)]

Pneumococcal disease is a serious global public health problem and a leading cause of morbidity and mortality of children and adults in China. Antibiotics are commonly used to treat pneumococcal disease. However, antibiotic resistance to Streptococcus pneumoniae has become a severe problem around the world due to widespread antibiotic use. Immunoprophylaxis of pneumococcal disease with pneumococcal vaccines is therefore of great importance. In this article, we review the etiology, clinical presentation, epidemiology, and disease burden of pneumococcal disease and the vaccinology of pneumococcal vaccines. Our review is based on the Expert Consensus on Immunoprophylaxis of Pneumococcal Disease (2017 version), the Pneumococcal Vaccines WHO Position Paper (2019), and recent national and international scientific advances. This consensus article aims to provide public health and vaccination staff with appropriate evidence for pneumococcal vaccine use and to improve professional capacity for pneumococcal disease prevention and control.

[Expert consensus on immunoprophylaxis of pneumococcal disease (2020 version)]

Pneumococcal disease is a serious global public health problem and a leading cause of morbidity and mortality of children and adults in China. Antibiotics are commonly used to treat pneumococcal disease. However, antibiotic resistance to Streptococcus pneumoniae has become a severe problem around the world due to widespread antibiotic use. Immunoprophylaxis of pneumococcal disease with pneumococcal vaccines is therefore of great importance. In this article, we review the etiology, clinical presentation, epidemiology, and disease burden of pneumococcal disease and the vaccinology of pneumococcal vaccines. Our review is based on the Expert Consensus on Immunoprophylaxis of Pneumococcal Disease (2017 version), the Pneumococcal Vaccines WHO Position Paper (2019), and recent national and international scientific advances. This consensus article aims to provide public health and vaccination staff with appropriate evidence for pneumococcal vaccine use and to improve professional capacity for pneumococcal disease prevention and control.

Pneumococcal conjugate vaccine primes mucosal immune responses to pneumococcal polysaccharide vaccine booster in Papua New Guinean children

Introduction

Invasive pneumococcal disease remains a major cause of hospitalization and death in Papua New Guinean (PNG) children. We assessed mucosal IgA and IgG responses in PNG infants vaccinated with pneumococcal conjugate vaccine (PCV) followed by a pneumococcal polysaccharide vaccine (PPV) booster.

Methods

Infants received 7-valent PCV (7vPCV) in a 0–1–2 (neonatal) or 1–2-3-month (infant) schedule, or no 7vPCV (control). At age 9 months all children received 23-valent PPV (23vPPV). IgA and IgG to 7vPCV and non-7vPCV (1, 5, 7F, 19A) serotypes were measured in saliva collected at ages 1, 2, 3, 4, 9, 10 and 18 months (131 children, 917 samples). Correlations were studied between salivary and serum IgG at 4, 10 and 18 months.

Results

Salivary IgA and IgG responses overall declined in the first 9 months. Compared to non-7vPCV recipients, salivary IgA remained higher in 7vPCV recipients for serotypes 4 at 3 months, 6B at 3 months (neonatal), and 14 at 3 (neonatal), 4 and 9 months (infant); and for salivary IgG for serotypes 4 at 3, 4 and 9 months, 6B at 9 months, 14 at 4 (neonatal) and 9 months, 18C at 3, 4, and 9 (infant) months, and 23F at 4 months. Following 23vPPV, salivary 7vPCV-specific IgA and IgG increased in 7vPCV-vaccinated children but not in controls; and salivary IgA against non-PCV serotypes 5 and 7F increased in 7vPCV recipients and non-recipients. Salivary and serum IgG against 7vPCV-serotypes correlated in 7vPCV-vaccinated children at 4 and 10 months of age.

Conclusions

PCV may protect high-risk children against pneumococcal colonization and mucosal disease by inducing mucosal antibody responses and priming for mucosal immune memory that results in mucosal immune responses after booster PPV. Saliva can be a convenient alternative sample to serum to study PCV-induced systemic IgG responses.

Serotype distribution of Streptococcus pneumoniae isolated from children hospitalized in Beijing children's hospital (2013-2019)

BACKGROUND

Streptococcus pneumoniae can cause many infectious diseases among children, and relevant vaccines have not been scheduled into the National Immunization Program in China. The serotype distribution of Streptococcus pneumoniae is essential information used to evaluate the value of pneumococcal vaccines and formulate immunization strategies.

METHODS

Streptococcus pneumoniae isolates, identified as the disease pathogens, were collected from children hospitalized in Beijing Children's Hospital from 2013 to 2019. The serotype was detected by the Quellung reaction.

RESULTS

A total of 903 isolates of Streptococcus pneumoniae were collected, among which 809 were from non-invasive infections and 94 were from invasive infections. The non-invasive isolates were mainly isolated from respiratory secretions (49.4%) and bronchoalveolar lavage fluid (38.9%), while invasive isolates were from venous blood (5.4%), cerebrospinal fluid (2.8%) and pleural effusion (2.8%). The leading serotypes were 19F (36.0%), 19A (13.6%), 23F (9.4%), 14 (8.9%), 6A (6.9%), and 6B (5.3%). The overall coverage rates of 10-, 13-, 15-, 20-valent pneumococcal conjugate vaccines (PCV10, PCV13, PCV15, PCV20) and 23-valent pneumococcal polysaccharide vaccine (PPV23) as well as Pneumosil (a 10-valent pneumococcal conjugate vaccine) were 61.6%, 83.2%, 83.4%, 88.0%, 82.4% and 81.6%, respectively. The coverage rates of PCV13, PCV15 and PPV23 in isolates from invasive infections were significantly higher than those from non-invasive infections. The coverage rates of Pneumosil, either on the whole or among different age groups or different infections, were significantly higher than those of PCV10.

CONCLUSIONS

Serotypes 19F, 19A, 23F, 14, 6A and 6B were the most common types among the isolates. As for pneumococcal vaccines available now, the coverage rate of PCV13 was high, especially in isolates from invasive infections. The promotion of PCV13 or further high valent vaccines might be of greater benefit in preventing pneumococcal infections than other pneumococcal vaccines in children.

Isolating polysaccharide IgG pneumococcal antibody responses by pre-adsorption of conjugate vaccine serotypes: A modified approach for the conjugate vaccine era

BACKGROUND

Assessment of pure polysaccharide response to the 23-valent pneumococcal polysaccharide vaccine (PPV23) can be biased by previous exposure to the conjugate vaccine (PCV). We applied pre-analytical modification to the existing ELISA by pre-incubating serum with PCV.

METHODS

PCV-adsorbed and non-adsorbed sera were prepared before measuring the concentration of anti-pneumococcal capsular polysaccharide (PCP) IgG antibodies by the whole pneumococcal ELISA. Paired pre and post-pneumococcal vaccination sera from 73 subjects were analyzed and the baseline anti-PCP IgG for each sample was subtracted from the post-vaccination value to measure vaccine responses. Absolute change in titers and fold changes were then compared between both methods.

RESULTS

In the PCV-vaccinated group (n = 28), pre-adsorption with PCV significantly reduced the vaccine responses compared to non-adsorbed sera [median increase in anti-PCP titers: 27.55 mg/l and 45.98 mg/l, respectively]. In addition, the median fold change dropped significantly from 3.026 to 2.313. In PPV23-vaccinated immunocompetent subjects (n = 28) there was a significant difference in anti-PCP responses with PCV adsorption [median values: 73.71 mg/l without and 51.04 mg/l with adsorption]. All the antibody deficiency patients (n = 17) displayed poor PPV23 responses. Although PPV23 responsiveness was not statistically different between both methods, we have observed a trend for lower anti-PCP IgG titers in PCV-adsorbed sera compared to non-adsorbed ones. Serotype-specific IgG analysis using a multiplexed bead-based immunoassay performed on 10 paired samples confirmed that the adsorption observed is specific to PCV serotypes.

CONCLUSION

Pre-analytical modification to the conventional ELISA by removing the PCV-specific serotypes may differentiate true polysaccharide response from recall response induced by previous PCV vaccination.

Defining Polysaccharide Antibody Deficiency: Measurement of Anti-Pneumococcal Antibodies and Anti-Salmonella typhi Antibodies in a Cohort of Patients with Recurrent Infections

BACKGROUND

The correlation between different methods for the detection of pneumococcal polysaccharide vaccine (PPV) responses to diagnose specific polysaccharide antibody deficiency (SAD) is poor and the criteria for defining a normal response lack consensus. We previously proposed fifth percentile (p5) values of PPV responses as a new cutoff for SAD.

OBJECTIVE

To analyze the association of SAD (determined by either World Health Organization (WHO)-standardized ELISA or multiplex bead-based assay) with abnormal response to Salmonella (S.) typhi Vi vaccination in a cohort of patients with recurrent infections.

METHODS

Ninety-four patients with a clinical history suggestive of antibody deficiency received PPV and S. typhi Vi vaccines. Polysaccharide responses to either 3 or 18 pneumococcal serotypes were measured by either the WHO ELISA or a multiplex in-house bead-based assay. Anti-S. typhi Vi IgG were measured by a commercial ELISA kit. Allohemagglutinins (AHA) were measured by agglutination method.

RESULTS

Based on the American Academy of Allergy, Asthma and Immunology (AAAAI) criteria for WHO ELISA, 18/94 patients were diagnosed with SAD and 22/93 based on serotype-specific p5 cutoffs for bead-based assay. The association between the two methods was significant, with 10 subjects showing abnormal response according to both techniques. Abnormal response to S. typhi Vi vaccination was found in 7 patients, 6 of which had SAD. No correlation was found between polysaccharide response and AHA, age, or clinical phenotype.

CONCLUSION

The lack of evidence-based gold standards for the diagnosis of SAD represents a challenge in clinical practice. In our cohort, we confirmed the insufficient correlation between different methods of specific PPV response measurement, and showed that the S. typhi Vi response was not contributive. Caution in the interpretation of results is warranted until more reliable diagnostic methods can be validated.

Vaccines to Prevent Pneumococcal Community-Acquired Pneumonia

Streptococcus pneumoniae is the most frequent pathogen in community-acquired pneumonia and also causes invasive diseases like bacteremia and meningitis. Young children and elderly are especially at risk for pneumococcal diseases and are, therefore, eligible for pneumococcal vaccination in most countries. This reviews provides an overview of the current epidemiology of pneumococcal infections, history and evidence of available pneumococcal polysaccharide and conjugate vaccines, and current recommendations.

Race-related differences in functional antibody response to pneumococcal vaccination in HIV-infected individuals

BACKGROUND

Both HIV positivity and African American (AA) ethnicity are associated with increased incidence of invasive pneumococcal disease (IPD). Poor immune response to pneumococcal polysaccharide-based vaccines may contribute to the race related increased frequency of IPD in African American HIV positive individuals.

METHODS

Caucasian and AA HIV-infected (HIV+) individuals 40-65 years old with CD4+ T cells/µl (CD4) >200 on antiretroviral therapy (ART) received either the 13-valent pneumococcal conjugate vaccine (PCV) followed by the 23-valent pneumococcal polysaccharide vaccine (PPV) or PPV only. Serum IgG, IgM and opsonophagocytic antibody responses to serotypes 14 and 23F as well as serum IgG and opsonophagocytic antibody responses to serotype 19A were measured pre- and post-vaccination. We measured serum markers of inflammation in all participants and performed single cell gene expression profiling at the baseline by HD Biomark in Caucasians and African Americans.

RESULTS

There were no significant differences in pre-immunization inflammatory markers or post-vaccination IgG and IgM concentrations between Caucasian and African American participants. However, we found significantly lower opsonophagocytic activity in response to serotypes 14 and 19A in the AA group compared to the Caucasian group. There was no association between inflammatory markers and immune response to vaccination, however we found extensive biomodal variation in gene expression levels in single IgM+ memory B cells. Differentially expressed genes may be related to differences in the immune response between ethnic groups.

CONCLUSIONS

Distinct racial differences were found in the functional immune response following either PPV and/or PCV/PPV immunization in HIV-positive adults, although these differences were serotype dependent. Decreased ability to respond to vaccination may in part explain racial disparities in pneumococcal disease epidemiology. ClinicalTrials.gov ID: NCT03039491.

The impact of pneumococcal vaccination on pneumonia mortality among the elderly in Japan: a difference-in-difference study

BACKGROUND

It is plausible that the routine immunization among infants using pneumococcal conjugate vaccine 13 (PCV13) from 2013 and among the elderly using pneumococcal polysaccharide vaccine 23 (PPV23) from 2014 contributed to reducing the pneumonia mortality among the elderly in Japan. The present study aimed to estimate the causal effect of this vaccination on pneumonia mortality, using the available cause-of-death data and employing a difference-in-difference (DID) design.

METHODS

Two types of mortality data, that is, prefecture-dependent and age- and gender-specific mortality data, from 2003 to 2017 were retrieved. We used mortality due to malignant neoplasm and heart disease as control groups and employed a DID design with an assumed parallel mortality trend between pneumonia and control group mortality since 2013 to estimate the causal effect of pneumococcal vaccination from 2014.

RESULTS

Our estimation based on malignant neoplasm and heart disease as controls indicated that the reduced pneumonia mortality in 2017 owing to pneumococcal vaccination was as large as 41.9 (33.2, 50.6) and 31.2 (23.8, 38.6) per 100,000 individuals, respectively. The largest mortality reduction was observed for the oldest group (aged ≥90 years), especially among men.

DISCUSSION

The pneumococcal vaccination program, perhaps mainly represented by high vaccination coverage of PCV13 among children and partly by PPV23 administration with low coverage among the elderly in Japan, was shown to have reduced the pneumonia mortality in the elderly at the population level.

Effectiveness of 23-Valent Polysaccharide Pneumococcal Vaccine and Changes in Invasive Pneumococcal Disease Incidence from 2000 to 2017 in Those Aged 65 and Over in England and Wales

BACKGROUND

Invasive Pneumococcal Disease (IPD) is a major public health concern. The effectiveness of 23-valent polysaccharide pneumococcal vaccine (PPV23) against IPD in older age-groups is not fully understood. We measured PPV23 effectiveness against IPD and interpreted changes in IPD incidence between 2000 and 2017.

METHODS

Public Health England conducts enhanced national IPD surveillance in England and Wales. The indirect cohort method was used to estimate PPV23 effectiveness against IPD in individuals aged ≥ 65 years eligible for PPV23 vaccination during 2012-2016. IPD incidence in 2016/17 was compared to rates during 2000-2003, when neither PPV23 nor pneumococcal conjugate vaccines (PCVs) were routinely used in England and Wales.

FINDINGS

PPV23 effectiveness, irrespective of time since vaccination, was 27% (95% CI, 17-35) after adjusting for age, co-morbidity and year of infection. Vaccine effectiveness reduced non-significantly (p = 0.13) with time since vaccination, from 41% (95% CI, 23-54) for those vaccinated within two years, to 34% (95% CI, 16-48) for those vaccinated 2-4 years previously, and 23% (95% CI, 12-32) for those vaccinated ≥ 5 years previously. Vaccine effectiveness did not vary significantly by age but was highest in previously healthy individuals (45%; 95%CI, 27-59). IPD incidence for PPV23 serotypes not included in the PCVs did not decrease after routine PPV23 use but increased significantly since PCV introduction in 2006.

INTERPRETATION

PPV23 offers moderate short-term protection against IPD in older adults. PPV23 serotypes comprise an increasing proportion of IPD cases in older adults because of serotype replacement following routine PCV use in children.

FUNDING

European Union's Horizon 2020.

[Adult community acquired pneumonia vaccination: 2018 Update of the positioning of the Pneumonia Prevention Expert Group]

Community-acquired pneumonia (CAP) continues to be an important cause of morbidity and mortality in adults. The aim of this study is to update the 2016 practical prevention guidelines for CAP through vaccination in Spain, based on the available vaccines, as well as the evidence using a literature review and expert opinion. Vaccines against pneumococcus and influenza continue to be the main prevention tools available against CAP, and can contribute to reduce the burden of disease due to CAP and its associated complications. The available evidence supports the priority indications established in these guidelines, and it would be advisable to try to achieve a widespread dissemination and implementation of these recommendations in routine clinical practice.

[Expert consensus on immunization for prevention of pneumococcal disease in China (2017)]

Pneumococcal disease is one of the serious global public health problems, and an important leading cause of the morbidity and mortality of children and adults in China. Currently, antibiotics are the most choices for its clinical treatment. However, antibiotic resistance of Streptococcus pneumoniae has become a severe problem around the world due to the wide use of antibiotics. Hence, the prevention of pneumococcal disease by using pneumococcal vaccines is of great importance. In this article, we reviewed the etiology, clinic, epidemiology, disease burden of pneumococcal disease, and the vaccinology of pneumococcal vaccines, based on the Pneumococcal Vaccines WHO Position Paper (2012) and other latest evidence globally, to introduce comprehensive knowledge of pneumococcal disease, and for the purpose to improve the capacity of the professionals working on pneumococcal disease control and prevention and to provide appropriate evidences of pneumococcal vaccine applications for people who are engaged in public health and immunization vaccination.

Rationale and methods of a randomized controlled trial of immunogenicity, safety and impact on carriage of pneumococcal conjugate and polysaccharide vaccines in infants in Papua New Guinea

BACKGROUND

Children in third-world settings including Papua New Guinea (PNG) experience early onset of carriage with a broad range of pneumococcal serotypes, resulting in a high incidence of severe pneumococcal disease and deaths in the first 2 years of life. Vaccination trials in high endemicity settings are needed to provide evidence and guidance on optimal strategies to protect children in these settings against pneumococcal infections.

METHODS

This report describes the rationale, objectives, methods, study population, follow-up and specimen collection for a vaccination trial conducted in an endemic and logistically challenging setting in PNG. The trial aimed to determine whether currently available pneumococcal conjugate vaccines (PCV) are suitable for use under PNG's accelerated immunization schedule, and that a schedule including pneumococcal polysaccharide vaccine (PPV) in later infancy is safe and immunogenic in this high-risk population.

RESULTS

This open randomized-controlled trial was conducted between November 2011 and March 2016, enrolling 262 children aged 1 month between November 2011 and April 2014. The participants were randomly allocated (1:1) to receive 10-valent PCV (10vPCV) or 13-valent PCV (13vPCV) in a 1-2-3-month schedule, with further randomization to receive PPV or no PPV at age 9 months, followed by a 1/5th PPV challenge at age 23 months. A total of 1229 blood samples were collected to measure humoral and cellular immune responses and 1238 nasopharyngeal swabs to assess upper respiratory tract colonization and carriage load. Serious adverse events were monitored throughout the study. Of the 262 children enrolled, 87% received 3 doses of PCV, 79% were randomized to receive PPV or no PPV at age 9 months, and 67% completed the study at 24 months of age with appropriate immunization and challenge.

CONCLUSION

Laboratory testing of the many samples collected during this trial will determine the impact of the different vaccine schedules and formulations on nasopharyngeal carriage, antibody production and function, and immune memory. The final data will inform policy on pneumococcal vaccine schedules in countries with children at high risk of pneumococcal disease by providing direct comparison of an accelerated schedule of 10vPCV and 13vPCV and the potential advantages of PPV following PCV immunization.

TRIAL REGISTRATION

ClinicalTrials.gov CTN NCT01619462, retrospectively registered on May 28, 2012.

Functional immune responses to 11 non-PCV13 serotypes after immunization with a 23-valent pneumococcal polysaccharide vaccine in older adults

BACKGROUND

The 23-valent pneumococcal polysaccharide vaccine (PPSV23) has been recommended for adults aged ≥65years. To evaluate functional immune response against the additional 11 serotypes that are included in PPSV23, but not the 13-valent pneumococcal conjugate vaccine (PCV13), serotype-specific anti-pneumococcal antibodies were examined using an opsonophagocytic assay (OPA).

METHODS

Participants ≥65years of age that were naïve to the pneumococcal vaccine were enrolled. They were divided into two groups according to their age: group 1 (N=30; aged 65-74years) and group 2 (N=32; aged ≥75years). The functional antibody response prior to and 4weeks post-immunization with PPSV23 was determined, using a multiplexed OPA (MOPA) for 11 pneumococcal serotypes (2, 8, 9N, 10A, 11A, 12F, 15B, 17F, 20B, 22F, and 33F).

RESULTS

Geometric mean OPA titers (GMTs) to 11 serotypes were significantly increased in both groups post-immunization compared to those prior to immunization. The GMTs for all serotypes were not significantly different between the two groups after immunization. The proportion of subjects with OPA titers post-immunization of ≥8 and ≥64 was 93-100% and 80-100% for the 11 serotypes, respectively, while subjects with a ≥4-fold increase in OPA titers ranged from 9 to 90% for the 11 serotypes.

CONCLUSIONS

This study revealed that PPSV23 vaccination induced significant functional immune responses to 11 non-PCV13 serotypes in older adults. The MOPA has been shown to be a useful tool for future application in evaluating new PCVs in older adults. The clinical trial registration number is KCT 0001963 (CRIS, https://cris.nih.go.kr/cris/en/).

Pneumococcal vaccination in patients with systemic lupus erythematosus: A multicenter placebo-controlled randomized double-blind study

BACKGROUND

Invasive pneumococcal disease and respiratory tract infections are both frequent and severe in patients with systemic lupus erythematosus (SLE). This study aimed to compare the immunological efficacy and safety of pneumococcal vaccination with the 23-valent polysaccharide (PPS) vaccine alone to a sequential immunization with the 7-valent pneumococcal conjugate (PnCj) vaccine followed by PPS in patients with SLE and stable diseaase.

METHODS

Multicenter randomized placebo-controlled double-blind trial: PPS vaccine alone (placebo-PPS group) or PnCj vaccine followed by PPS vaccine (PnCj-PPS group) 24weeks later. The primary endpoint was the rate of responders at week 28 to at least 5 of the 7 serotypes (4, 6B, 9V, 14, 18C, 19F and 23F) shared by both PPS and PnCj. Pneumococcal IgG antibodies' opsonophagocytic activity (OPA) were also assessed.

RESULTS

Twenty-five patients in the placebo-PPS group and 17 in the PnCj-PPS group were included in a modified intention-to-treat analysis. The primary endpoint was reached in 72% (18/25) in the placebo-PPS and 76% (13/17) in the PnCj-PPS group (p=0.75). There was no difference in the rates of responders with OPA. At week 52, 13/18 (72%) patients in the placebo-PPS group and 10/13 (77%) patients in the PnCj-PPS group (p=0.77) that met the primary endpoint at week 28 were still responders to ≥5/7 serotypes shared by both PPS and PnCj vaccines. Nine SLE flares were reported in 6 patients (4 in the placebo-PPS and 2 in the PnCj-PPS groups respectively, p=0.70).

CONCLUSION

Sequential administration of PnCj vaccine followed by PPS vaccine is safe and shows short-term immunological efficacy in patients with SLE but was not superior to the PPS vaccine alone.

TRIAL REGISTRATION

www.clinicaltrials.gov, NCT NCT00611663.

A case series evaluating the serological response of adult asthma patients to the 23-valent pneumococcal polysaccharide vaccine

BACKGROUND

Asthma is an independent risk factor for invasive pneumococcal disease; however, the immune response of adult asthma patients to pneumococcal vaccination is unknown. We explore the serologic response of patients with moderate to severe asthma to the 23-valent pneumococcal polysaccharide vaccine (PPSV23).

METHODS

Seventeen moderate to severe adult asthma patients that had not been vaccinated against pneumococcus over the 5 previous years were prospectively recruited from a tertiary care asthma clinic. Serum was analyzed for the presence of antibodies to five capsular polysaccharide (CP) antigens (6B, 9V, 19A, 19F, 23F) before and 4 weeks after PPSV23 vaccination.

RESULTS

There was a wide variability in baseline anti-CP antibody concentrations. Other than for serotype 19A, our patients frequently have baseline anti-CP antibody concentrations below 1 µg/mL (35% for serotype 19F, 41% for serotypes 9V and 23F, and 59% for serotype 6B). All post-vaccination geometric mean antibody concentrations were significantly higher than baseline. In the 31 tests where the baseline antibody concentration was <1 µg/mL, 77.4% had at least a twofold increase post-vaccination. Despite this, a large proportion of post-vaccination anti-CP antibody concentrations remained <1 µg/mL (51.6% of tests). Nine patients had at least one anti-CP antibody concentration <1 µg/mL post-vaccination. There was no difference between these patients and the remaining eight patients in demographic or clinical variables.

CONCLUSIONS

Patients with moderate to severe asthma have variable baseline and low post-vaccination antibody concentrations to common CP antigens included in the PPSV23 vaccine. The clinical relevance of these observations remains to be determined since the threshold concentration in adults required for clinical protection from invasive pneumococcal disease is uncertain.

The 23-valent pneumococcal polysaccharide vaccine in patients with rheumatoid arthritis: a double-blinded, randomized, placebo-controlled trial

Background

Pneumococcal pneumonia is the most frequent form of pneumonia. We herein assessed the effectiveness of the 23-valent pneumococcal polysaccharide vaccine (PPSV23) in the prevention of pneumonia overall in rheumatoid arthritis (RA) patients at risk for infections. We hypothesized that PPSV23 vaccination is superior in preventing pneumococcal pneumonia compared with placebo in RA patients.

Methods

A prospective, multicenter, double-blinded, randomized, placebo-controlled (1:1) trial was conducted across departments of rheumatology in Japanese National Hospital Organization hospitals. RA patients (n = 900) who had been treated with biological or immunosuppressive agents were randomly assigned PPSV23 or placebo (sodium chloride). The primary endpoints were the incidences of all-cause pneumonia and pneumococcal pneumonia. The secondary endpoint was death from pneumococcal pneumonia, all-cause pneumonia, or other causes. Cox regression models were used to estimate the risk of pneumonia overall for the placebo group compared with the vaccine group.

Results

Seventeen (3.7%) of 464 patients in the vaccine group and 15 (3.4%) of 436 patients in the placebo group developed pneumonia. There was no difference in the rates of pneumonia between the two study groups. The overall rate of pneumonia was 21.8 per 1000 person-years for patients with RA. The presence of interstitial pneumonia (hazard ratio: 3.601, 95% confidence interval: 1.547–8.380) was associated with an increased risk of pneumonia in RA patients.

Conclusion

PPSV23 does not prevent against pneumonia overall in RA patients at relative risk for infections. Our results also confirm that the presence of interstitial lung disease is associated with pneumonia in Japanese patients with RA.

Trial registration

UMIN-CTR UMIN000009566. Registered 17 December 2012.

Pneumococcal polysaccharide vaccination administered early after neurotrauma or neurosurgery

OBJECTIVES

Pneumococcal vaccination is recommended to lower the risk of posttraumatic meningitis, and early vaccination may be of importance. After both trauma and central nervous system injury, immune-suppression may occur, which could affect T-cell function and the response to T-cell dependent vaccines. We therefore aimed to investigate the response to early vaccination with a T-cell independent pneumococcal polysaccharide vaccine (PPSV).

METHODS

Thirty-three patients with basilar skull fracture and 23 patients undergoing transsphenoidal pituitary gland surgery were vaccinated with PPSV within 10days after neurotrauma or neurosurgery. Twenty-nine neurosurgical patients vaccinated ⩾3weeks after neurotrauma or neurosurgery served as controls. Serotype-specific anti-polysaccharide binding IgG antibody levels to serotypes 4, 6B, 9V, 14, 18C, 19F and 23F were determined by enzyme immunoassay.

RESULTS

The vaccination was safe and a highly significant antibody response was found against all serotypes in all groups (p<0.001 for each of the serotypes). There were no differences between groups or in the group by time interaction in any of the serotypes. After early and late vaccination, protective levels were found in >80% for serotypes 9V, 14, 18C, 19F and 23F and in 70% and 50% for serotypes 6B and 4, respectively.

CONCLUSION

Patients vaccinated with PPSV within 10days after neurotrauma or neurosurgery respond similarly to those vaccinated after ⩾3weeks, indicating that PPSV can be administered early after neurotrauma or neurosurgery.

CLINICAL TRIALS REGISTRATION

NCT02806284.

Response to pneumococcal polysaccharide vaccine in children with asthma, and children with recurrent respiratory infections, and healthy children

BACKGROUND

To analyse specific immune response to the 23-valent pneumococcal polysaccharide vaccine by measuring pneumococcal antibodies in children with asthma and with respiratory recurrent infection (RRI) as compared to healthy children.

METHODS

The study included 60 children, divided into three groups: 20 with asthma, 20 with RRI, and 20 healthy controls. Post-vaccination specific IgG antibodies against 10 pneumococcal serotypes (S1, S3, S4, S5, S6B, S9V, S14, S18C, S19F, and S23F) contained in the 23-valent pneumococcal polysaccharide vaccine (PPV) were measured. A specific IgG concentration ≥1.3μg/mL was considered a protective response to the vaccine. For statistical analysis, levels of specific IgG antibodies against each of the 10 pneumococcal serotypes were compared across the three groups of children using the x(2) test.

RESULTS

All of the children showed antipneumococcal antibody levels >1.3μg/mL for over 70% of the serotypes, considered within the normal range of response. Average IgG antibody levels and percentages of children protected were statistically comparable among the three groups studied.

CONCLUSION

The asthmatic children without RRI had pneumococcal antibody levels and percentages of serotype-specific protection to PPV comparable to those of healthy children. Asthmatic children with recurrent infections should be evaluated for specific antibody deficiency (SAD). Because asthma patients are at high risk for invasive pneumococcal infections, it would be worthwhile to explore systematic administration of PPV in children over the age of two years who have not received a pneumococcal conjugate vaccine, considering the positive response to PPV reported here.

Quantitative and Functional Antibody Responses to the 13-Valent Conjugate and/or 23-Valent Purified Polysaccharide Vaccine in Aging HIV-Infected Adults

BACKGROUND

The number of aging human immunodeficiency virus-infected (HIV+) individuals living in the United States has substantially grown over the past two decades. Advanced age and HIV infection both increase susceptibility to Streptococcus pneumoniae infection due to B cell dysfunction. The combined impact of these factors on pneumococcal vaccine responses remains unknown.

METHODS

We assessed serum immunoglobulin (Ig) G and IgM levels and opsonophagocytic killing assay (OPA) titers to pneumococcal serotypes 14 and 23F in HIV+ subjects and HIV-uninfected (HIV-) controls 50-65 years old. HIV+ individuals with CD4⁺ T cells/μl (CD4) >200 and ≥1 year of antiretroviral therapy (ART) received either a dose of the 13-valent pneumococcal conjugate vaccine followed by the 23-valent pneumococcal polysaccharide vaccine 8 weeks later (PCV/PPV) as currently recommended (n=15) or a single dose of PPV only (n=22). HIV- controls received PCV/PPV (n=14).

RESULTS

HIV+ PCV/PPV and PPV groups exhibited similar increases in IgG levels and OPA titers for both serotypes after immunization. Postvaccination IgM levels for serotype 23F, but not 14, were significantly higher in HIV+ PCV/PPV compared to PPV groups. IgG and IgM levels for serotype 14 and OPA titers to serotype 23F were significantly reduced in HIV+ compared to HIV- PCV/PPV groups. Serotype-specific IgG levels correlated with OPA titers for all groups.

CONCLUSIONS

Our data suggest that the recommended PCV/PPV regimen may not significantly improve quantitative or functional antibody responses compared to PPV only in aging HIV+ subjects. Continued efforts aimed at improving vaccine responses in this high risk population are warranted.

No long-term evidence of hyporesponsiveness after use of pneumococcal conjugate vaccine in children previously immunized with pneumococcal polysaccharide vaccine

BACKGROUND

A randomized controlled trial in Fiji examined the immunogenicity and effect on nasopharyngeal carriage after 0, 1, 2, or 3 doses of 7-valent pneumococcal conjugate vaccine (PCV7; Prevnar) in infancy followed by 23-valent pneumococcal polysaccharide vaccine (23vPPV; Pneumovax) at 12 months of age. At 18 months of age, children given 23vPPV exhibited immune hyporesponsiveness to a micro-23vPPV (20%) challenge dose in terms of serotype-specific IgG and opsonophagocytosis, while 23vPPV had no effect on vaccine-type carriage.

OBJECTIVE

This follow-up study examined the long-term effect of the 12-month 23vPPV dose by evaluating the immune response to 13-valent pneumococcal conjugate vaccine (PCV13) administration 4 to 5 years later.

METHODS

Blood samples from 194 children (now 5-7 years old) were taken before and 28 days after PCV13 booster immunization. Nasopharyngeal swabs were taken before PCV13 immunization. We measured levels of serotype-specific IgG to all 13 vaccine serotypes, opsonophagocytosis for 8 vaccine serotypes, and memory B-cell responses for 18 serotypes before and after PCV13 immunization.

RESULTS

Paired samples were obtained from 185 children. There were no significant differences in the serotype-specific IgG, opsonophagocytosis, or memory B-cell response at either time point between children who did or did not receive 23vPPV at 12 months of age. Nasopharyngeal carriage of PCV7 and 23vPPV serotypes was similar among the groups. Priming with 1, 2, or 3 PCV7 doses during infancy did not affect serotype-specific immunity or carriage.

CONCLUSION

Immune hyporesponsiveness induced by 23vPPV in toddlers does not appear to be sustained among preschool children in this context and does not affect the pneumococcal carriage rate in this age group.

Alterations in serotype-specific B cell responses to the 13-valent pneumococcal conjugate vaccine in aging HIV-infected adults

BACKGROUND

Advanced age and human immunodeficiency virus (HIV) infection are associated with increased pneumococcal disease risk. The impact of these factors on cellular responses to vaccination is unknown.

METHODS

HIV-infected (HIV+) individuals 50-65 years old with CD4(+) Tcells/μl (CD4) >200 on antiretroviral therapy (ART) ≥1 year received either the 13-valent pneumococcal conjugate vaccine followed by the 23-valent pneumococcal polysaccharide vaccine (PCV/PPV) or PPV only. HIV-uninfected (HIV-) controls received PCV/PPV. Phenotype distribution and surface expression of complement receptor CD21 and tumor necrosis factor superfamily receptors (TNFRs) were compared on serotype-specific B cells postvaccination.

RESULTS

Postvaccination serotype-specific B cell percentages were significantly lower in HIV+ PCV/PPV compared to PPV groups, but similar between HIV+ or HIV- PCV/PPV groups. Transmembrane activator and calcium-modulating cyclophilin ligand interactor (TACI)(+) serotype-specific B cell percentages were significantly decreased in HIV+ PCV/PPV compared to PPV groups. CD21(+) serotype-specific B cells were significantly higher in HIV- compared to HIV+ PCV/PPV groups.

CONCLUSIONS

An initial dose of PCV reduced the frequency, but not phenotype distribution, of serotype-specific B cells and also lowered TACI expression in aging HIV+ subjects postvaccination with PPV. These findings suggest that PCV does not enhance cellular responses to revaccination with PPV.

Evaluation of impact of 23 valent pneumococcal polysaccharide vaccine following 7 valent pneumococcal conjugate vaccine in Australian Indigenous children

BACKGROUND

High incidence and serotype diversity of invasive pneumococcal disease (IPD) in Indigenous children in remote Australia led to rapid introduction of 7-valent conjugate pneumococcal vaccine (7vPCV) at 2, 4 and 6 months in 2001, followed by 23-valent polysaccharide pneumococcal vaccine (23vPPV) in the second year of life. All other Australian children were offered 3 doses of 7vPCV without a booster from 2005. This study evaluated the impact of the unique pneumococcal vaccine schedule of 7vPCV followed by the 23vPPV booster among Indigenous Australian children.

METHODS

Changes in IPD incidence derived from population-based passive laboratory surveillance in Indigenous children <5 years eligible for 23vPPV were compared to non-Indigenous eligible for 7vPCV only from the pre-vaccine introduction period (Indigenous 1994-2000; non-Indigenous 2002-2004) to the post-vaccine period (2008-2010 in both groups) using incidence rate ratios (IRRs) stratified by age into serotype groupings of vaccine (7v and 13vPCV and 23vPPV) and non-vaccine types. Vaccine coverage was assessed from the Australian Childhood Immunisation Register.

RESULTS

At baseline, total IPD incidence per 100,000 was 216 (n=230) in Indigenous versus 55 (n=1993) in non-Indigenous children. In 2008-2010, IRRs for 7vPCV type IPD were 0.03 in both groups, but for 23v-non7v type IPD 1.2 (95% CI 0.8-1.8) in Indigenous versus 3.1 (95% CI 2.5-3.7) in non-Indigenous, difference driven primarily by serotype 19A IPD (IRR 0.6 in Indigenous versus 4.3 in non-Indigenous). For non-7vPCV type IPD overall, IRR was significantly higher in those age-eligible for 23vPPV booster compared to those younger, but in both age groups was lower than for non-Indigenous children.

CONCLUSION

These ecologic data suggest a possible "serotype replacement sparing" effect of 23vPPV following 7vPCV priming, especially for serotype 19A with supportive evidence from other immunogenicity and carriage studies. Applicability post 10vPCV or 13v PCV priming in similar settings would depend on local serotype distribution of IPD.

Pneumococcal Carriage and Vaccine Coverage in Retirement Community Residents

OBJECTIVES

To evaluate pneumococcal immunization in older adults living in retirement communities and to measure nasopharyngeal carriage of Streptococcus pneumoniae to better assess the potential for herd protection from the 13-valent pneumococcal conjugate vaccine (PCV-13) in these settings.

DESIGN

Cross-sectional observational study of adults aged 65 and older living in retirement communities to determine coverage with 23-valent pneumococcal vaccine (PPSV-23), coverage with PCV-13 in immuncompromised individuals according to 2012 Advisory Committee on Immunization Practices (ACIP) guidelines, and nasopharyngeal carriage of S. pneumoniae.

SETTING

Two retirement communities in North Carolina.

PARTICIPANTS

Older adults recruited between December 2013 and April 2014 (N = 21, 64.8% female, mean age 81.4).

MEASUREMENTS

A survey was used to assess chronic illnesses, immunization history, and potential risk factors for pneumococcal carriage; a chart review was used to confirm immunization history and abstract chronic conditions; and a nasopharyngeal swab was collected and cultured for S. pneumoniae.

RESULTS

Eighty-seven percent of participants reported receiving PPSV-23 since age 65. Of the 16.2% of participants with an immunocompromising condition, only one had received PCV-13. Nasopharyngeal carriage with S. pneumoniae was detected in 1.9% (95% confidence interval = 0.0-3.8%) of participants.

CONCLUSION

In this select sample, PPSV-23 coverage was high, but adherence to the ACIP recommendation for PCV-13 in immunocompromised groups was low. Nasopharyngeal carriage of S. pneumoniae was present, although infrequent, suggesting that immunization with PCV-13 could provide an individual benefit and a small degree of herd protection.

Specific Antibody Deficiencies

Patients with specific antibody deficiency (SAD) have a deficient immunologic response to polysaccharide antigens. Such patients experience sinopulmonary infections with increased frequency, duration, or severity compared with the general population. SAD is definitively diagnosed by immunologic challenge with a pure polysaccharide vaccine in patients 2 years old and older who have otherwise intact immunity, using the 23-valent pneumococcal polysaccharide vaccine as the current gold standard. Specific antibody deficiencies comprise multiple immunologic phenotypes. Treatment must be tailored based on the severity of symptoms. Most patients have a good prognosis. The deficiency may resolve over time, especially in children.

Functional immune responses to twelve serotypes after immunization with a 23-valent pneumococcal polysaccharide vaccine in older adults

BACKGROUND

The 23-valent pneumococcal polysaccharide vaccine (PPSV23) was introduced as part of the national immunization program for the elderly (≥65 years of age) in Korea on 2013. To evaluate immune responses in this population, serotype-specific anti-pneumococcal antibodies were studied with opsonophagocytic assay (OPA).

METHODS

Pneumococcal vaccine-naïve participants ≥65 years of age were enrolled. They were divided into two groups according to their age: 30 in (65-74 years) and 32 in group (≥75 years). The functional antibody response was determined by multiplexed OPA (MOPA) for 12 serotypes (1, 3, 4, 5, 6B, 7F, 9V, 14, 18C, 19A, 19F, and 23F) before and 4 weeks after vaccination with PPSV23.

RESULTS

Geometric mean titers (GMTs) to all tested serotypes significantly increased in both groups after vaccination compared to those before vaccination. There were no significant differences in either the fold rise (post-vaccination to pre-vaccination) or the percentage of participants with a ≥4-fold increase in OPA titers between two groups for any of the 12 serotypes. Following vaccination, GMT for serotype 9V was higher in group 1 than in group 2 (P=0.011).

CONCLUSIONS

PPSV23 induces functional immune response for 12 vaccine serotypes in both age groups. Further analysis is needed for the remaining 11 serotypes in the PPSV23, in order to develop a better understanding of the immune responses induced by PPV23 in older adults.

Long-term impact of pneumococcal polysaccharide vaccination on nasopharyngeal carriage in children previously vaccinated with various pneumococcal conjugate vaccine regimes

Previously, the Fiji Pneumococcal Project (FiPP) evaluated reduced dose immunization schedules that incorporated pneumococcal protein conjugate and/or polysaccharide vaccine (PCV7 and 23vPPV, respectively). Immune hyporesponsiveness was observed in children vaccinated with 23vPPV at 12 months of age compared with children who did not receive 23vPPV. Here we assess the long-term impact of 23vPPV vaccination on nasopharyngeal carriage rates and densities of Streptococcus pneumoniae, Haemophilus influenzae, Staphylococcus aureus and Moraxella catarrhalis. Nasopharyngeal swabs (n=194) were obtained from healthy children who participated in FiPP (now aged 5-7 years). S. pneumoniae were isolated and identified by standard culture-based methods, and serotyped using latex agglutination and the Quellung reaction. Carriage rates and densities of S. pneumoniae, H. influenzae, S. aureus and M. catarrhalis were determined using real-time quantitative PCR. There were no differences in the rate or density of S. pneumoniae, H. influenzae or M. catarrhalis carriage by PCV7 dose or 23vPPV vaccination in the vaccinated participants overall. However, differences were observed between the two main ethnic groups: Fijian children of Indian descent (Indo-Fijian) were less likely to carry S. pneumoniae, H. influenzae and M. catarrhalis, and there was evidence of a higher carriage rate of S. aureus compared with indigenous Fijian (iTaukei) children. Polysaccharide vaccination appeared to have effects that varied between ethnic groups, with 23vPPV vaccination associated with a higher carriage rate of S. aureus in iTaukei children, while there was a lower carriage rate of S. pneumoniae associated with 23vPPV vaccination in Indo-Fijian children. Overall, polysaccharide vaccination had no long-term impact on pneumococcal carriage, but may have impacted on S. aureus carriage and have varying effects in ethnic groups, suggesting current WHO vaccine schedule recommendations against the use of 23vPPV in children under two years of age are appropriate.

Immunogenicity and safety of concomitant MF59-adjuvanted influenza vaccine and 23-valent pneumococcal polysaccharide vaccine administration in older adults

BACKGROUND

Concomitant administration of influenza and pneumococcal vaccines facilitates their uptake by older adults; however, data on immunogenicity and safety of concomitant administration of adjuvanted trivalent inactivated influenza vaccine (aIIV3) and 23-valent pneumococcal polysaccharide vaccine (PPSV23) have not been reported.

METHODS

Subjects aged ≥65 years (N=224) were randomized 1:1:1:1 to receive MF59-aIIV3 alone, MF59-aIIV3+PPSV23 in contralateral arms, MF59-aIIV3+PPSV23 in the same arm or PPSV23 alone (Clinical Trial Number - NCT02225327). Hemagglutination inhibition assay and multiplex opsonophagocytic killing assay were used to compare immunogenicity after single or concomitant vaccination.

RESULTS

All groups met immunogenicity criteria for the influenza vaccine in older adults with similar seroconversion rates and geometric mean fold-increases, irrespective of concomitant vaccinations and injection site. For each pneumococcal serotype, opsonic index (OI) increased markedly after the PPSV23 vaccination, irrespective of the concomitant influenza vaccine. All subjects showed an OI≥8 for serotypes 6B, 18C and 19A post-vaccination, with a suggestion that the ipsilateral concomitant vaccination might be associated with higher OIs for some antigens. Local and systemic adverse events were more common in subjects receiving PPSV23 compared to those receiving aIIV3 alone.

CONCLUSIONS

No interference was observed with antibody responses to influenza or pneumococcal antigens when aIIV3 and PPSV23 were administered concomitantly.

The 23-valent pneumococcal polysaccharide vaccine is effective in elderly adults over 75 years old--Taiwan's PPV vaccination program

BACKGROUND

Pneumococcal infection is a serious cause of mortality and morbidity in the elderly. A nationwide pneumococcal polysaccharide vaccine (PPV) program for elderly adults aged 75 years and older was conducted in Taiwan in 2008. The efficacy of the PPV in this very elderly population was evaluated.

METHODS

The data were analyzed using the Taiwan National Health Insurance Research Database (NHIRD), the cause-of-death registration database and the invasive pneumococcal disease (IPD) notification database of Taiwan's Ministry of Health and Welfare. The efficacy of PPV administration in this very elderly population was evaluated using multivariate logistic regression after propensity score matching (PSM). The rates of IPD, death from IPD, pneumonia hospitalization, death from pneumonia, and all-cause mortality were compared for those who did and did not receive the PPV.

RESULTS

Among the 1078,955 eligible people, 318,257 (29.5%) received the PPV, and 760,698 (70.5%) were not vaccinated. Using PSM to adjust for confounding factors, including age, gender, influenza vaccination status, associated chronic diseases and health care utilization, those who received the PPV had significantly lower odds ratios (ORs) for IPD (OR=0.24, 95% CI=0.123-0.461, p<0.001), death from IPD (OR=0.09, 95% CI=0.011-0.704, p<0.022, p<0.001), pneumonia hospitalization (OR=0.40, 95% CI=0.395-0.415, p<0.001), death from pneumonia (OR=0.07, 95% CI=0.059-0.082, p<0.001), and all-cause mortality (OR=0.07, 95% CI=0.069-0.072, p<0.001) compared with those who were not vaccinated.

CONCLUSIONS

PPV vaccination in the previous year was associated with a 60% reduction in pneumonia hospitalization, a 76% reduction in IPD, and a greater than 90% reduction in death from pneumonia, IPD and all causes among people over 75 years old in Taiwan. Data from subsequent years in Taiwan and similar populations elsewhere are needed to evaluate the contribution of underlying variations in the mortality rate and the confounding effects of prior disease severity to these findings.

[Pneumococcal vaccination for prevention of pneumonia]

Aging of the immune system, so-called immunosenescence, is well documented as the cause of increased infection rates and severe, often complicated courses of infections in older adults. This is particularly true for pneumococcal pneumonia in older adults; therefore, the standing committee on vaccination of the Robert Koch Institute (STIKO) recommends a once only vaccination with 23-valent pneumococcal polysaccharide vaccine for all persons aged 60 years and over. Furthermore, the 13-valent pneumococcal conjugate vaccine is also available for administration in adults and is recommended by the STIKO for particular indications. The advantage of the pneumococcal conjugate vaccine is the additional induction of a T-cell dependent immune response that leads to good immunogenicity despite immunosenescence. Initial data from a recent randomized controlled trial, so far only presented at conferences, confirm that the conjugate vaccine also provides protection against non-bacteremic pneumococcal pneumonia, which is not provided by the polysaccharide vaccine. Thus, there are two vaccines for prevention of pneumococcal diseases: one with a broader range of serotype coverage but with an uncertain protection against non-bacteremic pneumococcal pneumonia and another one with less serotype coverage but more effective protection. Vaccination of children with the conjugate vaccine also leads to a rapid decrease of infections by the 13 vaccine serotypes even in adults because of herd protection effects. For prevention of pneumonia in older adults the additional benefit of a concurrent application of influenza vaccine and pneumococcal vaccine should be considered.

Comparison of the immunogenicity and safety of polysaccharide and protein-conjugated pneumococcal vaccines among the elderly aged 80 years or older in Japan: an open-labeled randomized study

An open-labeled randomized study was conducted to compare the immunogenicity and safety of polysaccharide (PPV23) or protein-conjugated pneumococcal vaccine (PCV7) among the elderly aged 80 years or older. A total of 105 nursing home residents were enrolled in this study. We analyzed the geometric mean concentration (GMC) of serotype-specific immunoglobulin G (IgG) and the geometric mean titer (GMT) of the opsonization index (OI) for serotypes 4, 6B, 9V, 14, 18C, 19F, and 23F. The GMCs of serotype-specific IgG and the GMTs of the OI significantly increased one month after vaccination in both groups for all seven serotypes evaluated. In the PCV7 group, study subjects with serotypes 4, 9V, 18C, and 23F exhibited statistically significant elevations in both serotype-specific IgGs and OIs compared to those of the PPV23 group. Both vaccines were tolerated without any severe adverse events, and no differences in systemic adverse events were observed between the two groups, although adverse reactions such as redness and localized swelling were more common in the PCV7 group. Our data demonstrated that the GMCs of serotype-specific IgG and the GMTs of the OI were higher in the PCV7 group compared to those in the PPV23 group. Our study also confirmed the safety of both the PCV7 and PPV23 vaccines in elderly people aged 80 years or older.

Evaluation of antibody levels over 3 years after 23-valent pneumococcal polysaccharide vaccination in patients with pulmonary diseases receiving steroids and immunosuppressive agents

OBJECTIVES

Pneumococcal capsular polysaccharide vaccine is a mainstay for prevention of Streptococcus pneumoniae infection in adults. There is the possibility that this vaccine is less effective in patients undergoing immunosuppressive therapy. In the present study, we aimed to evaluate the immune response following 23-valent pneumococcal polysaccharide vaccination in pulmonary disease patients receiving steroids and immunosuppressive agents (immunosuppressive group).

DESIGN AND METHODS

Antibody levels were measured over 3 years in the immunosuppressive group (median age: 68.5 years) and in aged-match pulmonary disease patients not being treated with immunosuppressive therapy (control group) using enzyme-linked immunosorbent assays.

RESULTS

The geometric mean antibody levels were significantly increased after vaccination in both groups (p < 0.05) and remained above baseline for 3 years. The fold increases 1 month after vaccination were 9.4 (95% confidence interval [CI]: 5.7-15.6) and 8.8 (95% CI: 5.8-13.2) in the immunosuppressive and control groups, respectively (p = 0.813). There was no significant difference in the proportion of subjects with a ≥ two-fold increase of antibody level between the immunosuppressive and control groups at any point.

CONCLUSIONS

These results suggest that immunization with the 23-valent pneumococcal polysaccharide vaccine was effective, even in patients undergoing immunosuppressive therapy and should be recommended for such patients.

Pneumococcal vaccines and the prevention of community-acquired pneumonia

Community-acquired pneumonia (CAP) is a disease that frequently affects children and adults throughout the world. As it places a considerable burden on society and, particularly, healthcare resources, any means of reducing its incidence and impact arouses great interest. A substantial number of paediatric and adult CAP cases are due to Streptococcus pneumoniae but, fortunately, there are effective vaccines available that are likely to have a significant impact on CAP-related medical, social and economic problems. The main aim of this paper is to evaluate the published evidence concerning the impact of pneumococcal vaccines on CAP in children and adults. The original 7-valent pneumococcal conjugate vaccine (PCV-7) completely modified the total burden of pneumococcal diseases in vaccinated children and unvaccinated contacts of any age. However, the existence of some problems moderately reducing its preventive efficacy has led to the development of PCVs with a larger number of pneumococcal serotypes, including those that were previously of marginal importance but now cause of severe disease. It is reasonable to think that these PCVs (particularly PCV13, which includes all of the most important serotypes emerging since the introduction of PCV7) will further reduce the importance of pneumococcal diseases, although it is still not clear whether the replacement of the 23-valent polysaccharide vaccine with PCV13 would be more protective in adults.

Sustained functional serotype-specific antibody after primary and secondary vaccinations with a pneumococcal polysaccharide vaccine in elderly patients with chronic lung disease

An observational study was conducted to determine immunogenicity before and after primary and secondary vaccinations with 23-valent pneumococcal polysaccharide vaccine in a cohort of 40 elderly patients with chronic lung diseases. Safety of this vaccine was also compared between primary and secondary vaccination. We analyzed serotype-specific immunoglobulin G (IgG) and the opsonization index (OI) for serotypes 6B, 14, 19F, and 23F and compared adverse local and systemic reactions. The levels of serotype-specific IgG and the OIs significantly increased 1 month after primary and secondary vaccinations. Peak levels of IgG after secondary vaccination were 5-20% lower than those after primary vaccination, while serotype-specific OIs after secondary vaccination were comparable with those after primary vaccination. The levels of serotype-specific IgG required for 50% killing significantly decreased 1 month after vaccination. These values for serotypes 14, 19F, and 23F were slightly elevated immediately before secondary vaccination, but those for serotype 6B did not change. After secondary vaccination, these values declined slightly for serotypes 14, 19F, and 23F and remained low for serotype 6B. Although self-limited local and systemic reactions were more frequent after secondary vaccination compared with primary vaccination, no serious systemic reaction was found after either vaccination. Our data suggest a sustained functional serotype-specific IgG after primary and secondary vaccination and confirmed the safety of secondary vaccination among elderly individuals with chronic lung disease.