The effectiveness of pneumococcal polysaccharide vaccine 23 (PPV23) in the general population of 50 years of age and older: A systematic review and meta-analysis

Evaluation of the decision-making process underlying the initial off-label use of vaccines: A scoping review

BACKGROUND

This scoping review aimed to assess the non-standardized decision-making process of National or International Immunization Technical Advisory Groups (NITAG) in developing novel off-label recommendations by examining the supportive evidence.

METHODS

We used the Joanna Briggs Institute framework. A search strategy was developed with a librarian to identify recommendations and evidence from peer-reviewed and gray literature until January 2022, using PubMed, Medline, EMBASE, clinicaltrials.gov, the International Clinical trials registry, governmental agency and pharmaceutical websites, the Global NITAG Network center website, and Google Scholar. Recommendations involving one of 26 pre-identified vaccine-preventable diseases, human use, and the introduction of a novel change across time and countries, were included. Evidence regarding efficacy/effectiveness, safety, or immunogenicity were included. Recommendations for fast-track approval, unlabeled or individual level off-label use, passive immunization, booster doses or provincial strategies were excluded. Only English and French documents were included. Two reviewers reviewed title/abstracts and full-text documents, and three performed data extraction. The primary outcome was the presence and elements of the evidence.

FINDINGS

Out of 4023 documents, 12 were included, and 116 were found through manual search. Over the 40-year span captured (1982-2018), most recommendations were from the last two decades and included evidence, except three from the 1990s. Most included safety (69.2%) and immunogenicity (65.4%) studies and randomized controlled trials (57.7%). Indication-based recommendations included RCTs more often (84.6%) than posology-based recommendations (30.8%). There was evidence involving populations or vaccines different from those in the recommendation.

INTERPRETATION

Critical outcomes evidence is not systematically included in off-label recommendations, nor must it involve the exact population or vaccine(s) of concern. However, in recent years, more off-label recommendations include critical outcome evidence, mainly RCTs.

Effectiveness of the 23-Valent Pneumococcal Polysaccharide Vaccine (PPV23) in Preventing Community-Acquired Pneumonia in Adults: A Population-Based Cohort Study

AIM

The aim was to assess the effectiveness of 23-valent pneumococcal polysaccharide vaccine (PPV23) in preventing CAP in adults.

METHODS

This was a population-based cohort study, followed up over 5 years (2015-2019), that included 47,768 persons aged ≥18 years assigned to three primary care centres. Data were retrospectively obtained from electronic medical records and databases. The vaccination effect was adjusted for potential confounders. Analyses were performed for the entire study population and for the ≥65 age subgroup.

RESULTS

The annual incidence of CAP (per 103 adult inhabitants) was 3.29 overall, and 8.08 and 2.93 for vaccinated and non-vaccinated persons, respectively. The non-adjusted effect of PPV23 on CAP was evidenced by HR = 2.80 (95% CI: 2.32-3.37), and after adjusting for possible confounders, PPV23 showed no significant independent effect on CAP in the overall population (HR = 1.14; p = 0.277) or in persons aged ≥65 years (HR = 1.30; p = 0.051). No protective effect was observed in persons vaccinated <2 years previously (HR = 1.17; p = 0.514).

CONCLUSIONS

PPV23 showed no effect in preventing CAP in adults aged ≥18 years or in the subgroup aged ≥65 years, even if vaccinated <2 years previously.

Global, regional, and national incidence and mortality burden of non-COVID-19 lower respiratory infections and aetiologies, 1990-2021: a systematic analysis from the Global Burden of Disease Study 2021

BACKGROUND

Lower respiratory infections (LRIs) are a major global contributor to morbidity and mortality. In 2020-21, non-pharmaceutical interventions associated with the COVID-19 pandemic reduced not only the transmission of SARS-CoV-2, but also the transmission of other LRI pathogens. Tracking LRI incidence and mortality, as well as the pathogens responsible, can guide health-system responses and funding priorities to reduce future burden. We present estimates from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 of the burden of non-COVID-19 LRIs and corresponding aetiologies from 1990 to 2021, inclusive of pandemic effects on the incidence and mortality of select respiratory viruses, globally, regionally, and for 204 countries and territories.

METHODS

We estimated mortality, incidence, and aetiology attribution for LRI, defined by the GBD as pneumonia or bronchiolitis, not inclusive of COVID-19. We analysed 26 259 site-years of mortality data using the Cause of Death Ensemble model to estimate LRI mortality rates. We analysed all available age-specific and sex-specific data sources, including published literature identified by a systematic review, as well as household surveys, hospital admissions, health insurance claims, and LRI mortality estimates, to generate internally consistent estimates of incidence and prevalence using DisMod-MR 2.1. For aetiology estimation, we analysed multiple causes of death, vital registration, hospital discharge, microbial laboratory, and literature data using a network analysis model to produce the proportion of LRI deaths and episodes attributable to the following pathogens: Acinetobacter baumannii, Chlamydia spp, Enterobacter spp, Escherichia coli, fungi, group B streptococcus, Haemophilus influenzae, influenza viruses, Klebsiella pneumoniae, Legionella spp, Mycoplasma spp, polymicrobial infections, Pseudomonas aeruginosa, respiratory syncytial virus (RSV), Staphylococcus aureus, Streptococcus pneumoniae, and other viruses (ie, the aggregate of all viruses studied except influenza and RSV), as well as a residual category of other bacterial pathogens.

FINDINGS

Globally, in 2021, we estimated 344 million (95% uncertainty interval [UI] 325-364) incident episodes of LRI, or 4350 episodes (4120-4610) per 100 000 population, and 2·18 million deaths (1·98-2·36), or 27·7 deaths (25·1-29·9) per 100 000. 502 000 deaths (406 000-611 000) were in children younger than 5 years, among which 254 000 deaths (197 000-320 000) occurred in countries with a low Socio-demographic Index. Of the 18 modelled pathogen categories in 2021, S pneumoniae was responsible for the highest proportions of LRI episodes and deaths, with an estimated 97·9 million (92·1-104·0) episodes and 505 000 deaths (454 000-555 000) globally. The pathogens responsible for the second and third highest episode counts globally were other viral aetiologies (46·4 million [43·6-49·3] episodes) and Mycoplasma spp (25·3 million [23·5-27·2]), while those responsible for the second and third highest death counts were S aureus (424 000 [380 000-459 000]) and K pneumoniae (176 000 [158 000-194 000]). From 1990 to 2019, the global all-age non-COVID-19 LRI mortality rate declined by 41·7% (35·9-46·9), from 56·5 deaths (51·3-61·9) to 32·9 deaths (29·9-35·4) per 100 000. From 2019 to 2021, during the COVID-19 pandemic and implementation of associated non-pharmaceutical interventions, we estimated a 16·0% (13·1-18·6) decline in the global all-age non-COVID-19 LRI mortality rate, largely accounted for by a 71·8% (63·8-78·9) decline in the number of influenza deaths and a 66·7% (56·6-75·3) decline in the number of RSV deaths.

INTERPRETATION

Substantial progress has been made in reducing LRI mortality, but the burden remains high, especially in low-income and middle-income countries. During the COVID-19 pandemic, with its associated non-pharmaceutical interventions, global incident LRI cases and mortality attributable to influenza and RSV declined substantially. Expanding access to health-care services and vaccines, including S pneumoniae, H influenzae type B, and novel RSV vaccines, along with new low-cost interventions against S aureus, could mitigate the LRI burden and prevent transmission of LRI-causing pathogens.

FUNDING

Bill & Melinda Gates Foundation, Wellcome Trust, and Department of Health and Social Care (UK).

Pneumococcal Vaccination Strategies in 50-Year-Olds to Decrease Racial Disparities: A US Societal Perspective Cost-Effectiveness Analysis

OBJECTIVES

This study assesses the impact of expanding pneumococcal vaccination to all 50-year-olds to decrease racial disparities by estimating from the societal perspective, the cost-effectiveness of 20-valent pneumococcal conjugate vaccine (PCV20) and 15-valent conjugate vaccine followed by 23-valent polysaccharide vaccine (PCV15/PPSV23) for 50-year-olds.

METHODS

A Markov model compared the cost-effectiveness of PCV20 or PCV15/PPSV23 in all general population 50- and 65-years-olds compared with current US recommendations and with no vaccination in US Black and non-Black cohorts. US data informed model parameters. Pneumococcal disease societal costs were estimated using direct and indirect costs of acute illness and of pneumococcal-related long-term disability and mortality. Hypothetical 50-year-old cohorts were followed over their lifetimes with costs and effectiveness discounted 3% per year. Deterministic and probabilistic sensitivity analyses assessed model uncertainty.

RESULTS

In Black cohorts, PCV20 for all at ages 50 and 65 was the least costly strategy and had greater effectiveness than no vaccination and current recommendation strategies, whereas PCV15/PPSV23 at 50 and 65 cost more than $1 million per quality-adjusted life year (QALY) gained compared with PCV20 at 50 and 65. In non-Black cohorts, PCV20 at 50 and 65 cost $62 083/QALY and PCV15/PPSV23 at 50 and 65 cost more than $1 million/QALY with current recommendations, again being more costly and less effective. In probabilistic sensitivity analyses, PCV20 at 50 and 65 was favored in 85.7% (Black) and 61.8% (non-Black) of model iterations at a $100 000/QALY gained willingness-to-pay threshold.

CONCLUSIONS

When considering the societal costs of pneumococcal disease, PCV20 at ages 50 and 65 years in the general US population is a potentially economically viable strategy, particularly in Black cohorts.

Pneumococcal vaccination and primary care presentations for acute respiratory tract infection and antibiotic prescribing in older adults

BACKGROUND

While the 23-valent pneumococcal polysaccharide vaccine (PPV23) has demonstrated its role in preventing severe pneumococcal disease, its impact on more non-specific conditions like acute respiratory tract infection (ARI) and lower respiratory tract infections (LRTI) remains unclear. We aimed to investigate the role of PPV23 in prevention of presentations for ARI and LRTI and related antibiotic prescriptions among older adults in primary care.

METHODS

Using a nationwide general practice dataset, we followed a cohort of regularly attending patients aged ≥65 years from 1 January 2014 until 31 December 2018 for presentations for ARI, LRTI, and related antibiotic prescriptions. Associations between PPV23 receipt and each outcome were assessed using a multiple failures survival model to estimate hazard ratios (HR) adjusted for age, sex, socioeconomic status, and various health measures.

RESULTS

A cohort of 75,264 patients aged ≥65 years (mean 75.4, 56% female) in 2014 was followed. The incidence of presentations for ARI, ARI-related antibiotic prescription, LRTI, and LRTI-related antibiotic prescription was 157.6, 76.0, 49.6, and 24.3 per 1000 person-years, respectively. Recent PPV23 vaccine receipt was associated with a small reduction in ARI presentations (adjusted HR vaccinated vs. unvaccinated 0.96; 95%CI 0.94-0.98; p = 0.002); however, there was no reduction in ARI-related antibiotic prescription, LRTI presentation, nor LRTI-related antibiotic prescription (adjusted HR were 0.99[95%CI 0.96-1.03], 1.04[95%CI 0.99-1.09], 1.07[95%CI 1.00-1.14]).

CONCLUSION

PPV23 vaccination in older adults may result in a small reduction in the incidence of total ARI presentations in primary care. However, the effect is small and residual confounding cannot be excluded.

Distinct baseline immune characteristics associated with responses to conjugated and unconjugated pneumococcal polysaccharide vaccines in older adults

Pneumococcal infections cause serious illness and death among older adults. The capsular polysaccharide vaccine PPSV23 and conjugated alternative PCV13 can prevent these infections; yet, underlying immunological responses and baseline predictors remain unknown. We vaccinated 39 older adults (>60 years) with PPSV23 or PCV13 and observed comparable antibody responses (day 28) and plasmablast transcriptional responses (day 10); however, the baseline predictors were distinct. Analyses of baseline flow cytometry and bulk and single-cell RNA-sequencing data revealed a baseline phenotype specifically associated with weaker PCV13 responses, which was characterized by increased expression of cytotoxicity-associated genes, increased frequencies of CD16+ natural killer cells and interleukin-17-producing helper T cells and a decreased frequency of type 1 helper T cells. Men displayed this phenotype more robustly and mounted weaker PCV13 responses than women. Baseline expression levels of a distinct gene set predicted PPSV23 responses. This pneumococcal precision vaccinology study in older adults uncovered distinct baseline predictors that might transform vaccination strategies and initiate novel interventions.

Baseline immune states (BIS) associated with vaccine responsiveness and factors that shape the BIS

Vaccines are among the greatest inventions in medicine, leading to the elimination or control of numerous diseases, including smallpox, polio, measles, rubella, and, most recently, COVID-19. Yet, the effectiveness of vaccines varies among individuals. In fact, while some recipients mount a robust response to vaccination that protects them from the disease, others fail to respond. Multiple clinical and epidemiological factors contribute to this heterogeneity in responsiveness. Systems immunology studies fueled by advances in single-cell biology have been instrumental in uncovering pre-vaccination immune cell types and genomic features (i.e., the baseline immune state, BIS) that have been associated with vaccine responsiveness. Here, we review clinical factors that shape the BIS, and the characteristics of the BIS associated with responsiveness to frequently studied vaccines (i.e., influenza, COVID-19, bacterial pneumonia, malaria). Finally, we discuss potential strategies to enhance vaccine responsiveness in high-risk groups, focusing specifically on older adults.

Effect of the 23-valent pneumococcal polysaccharide vaccine on the incidence of hospitalisation with pneumonia in adults aged ≥65 years: retrospective cohort study using a population-based database in Japan

OBJECTIVES

The effectiveness of the 23-valent pneumococcal polysaccharide vaccine (PPV23) in preventing pneumonia in older adults remains controversial. Some studies have suggested differences in the effectiveness according to age or sex.

METHODS

We conducted an observational study using the database of vaccine subsidisation data and health insurance claims data for a city in Japan. Participants were residents from 2014 to 2018 turning 65, 70, 75, 80, 85, 90 or 95 years during a given fiscal year, and PPV23 during the first year of observation were identified. We matched vaccinated and non-vaccinated individuals of the same age using propensity scores for vaccination. Incidence of hospitalisation with pneumonia was compared using Fine-Gray regression model. We summarised the results for each age using random-effects meta-analysis and conducted a subgroup analysis by sex.

RESULTS

A total of 102,136 participants were included, of whom 35% received PPV23. Propensity score matching selected 32,510 pairs of vaccinated and non-vaccinated individuals. Overall, PPV23 administration was associated with a decreased incidence of hospitalisation with pneumonia (17.2 vs. 20.4 per 1,000 person-years, sub-distribution hazard ratio: 0.84, 95% confidence interval: 0.77 to 0.91). Vaccine effectiveness was highest among those aged 70 years and decreased with increasing age. No statistically significant effect was observed in those aged 90 or 95 years. Vaccine effectiveness was observed in both males and females.

CONCLUSIONS

PPV23 was associated with an overall decrease in hospitalisation with pneumonia in older adults. However, vaccine effectiveness was significant in those aged 65 to 85 years but not in older population.

Strengths and weaknesses of pneumococcal conjugate vaccines

Multivalent vaccines addressing an increasing number of Streptococcus pneumoniae types (7-, 10-, 13-, 15-, 20-valent) have been licensed over the last 22 years. The use of polysaccharide-protein conjugate vaccines has been pivotal in reducing the incidence of invasive pneumococcal disease despite the emergence of non-vaccine serotypes. Notwithstanding its undoubtable success, some weaknesses have called for continuous improvement of pneumococcal vaccination. For instance, despite their inclusion in pneumococcal conjugate vaccines, there are challenges associated with some serotypes. In particular, Streptococcus pneumoniae type 3 remains a major cause of invasive pneumococcal disease in several countries.Here a deep revision of the strengths and weaknesses of the licensed pneumococcal conjugate vaccines and other vaccine candidates currently in clinical development is reported.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSION

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

Optimization of Elderly Influenza and Pneumococcal Immunization Programs in Beijing, China Using Health Economic Evaluations: A Modeling Study

(1) Background: Currently, residents ≥ 60 and ≥65 years old in Beijing, China, are eligible for free influenza and pneumococcal polysaccharide vaccines (PPSV23), respectively. The present study aimed to assess the cost-effectiveness of current and alternative strategies of dual influenza and PPSV23 vaccination among the elderly in Beijing. (2) Methods: We developed a Markov state-transition model to compare the costs and the quality-adjusted life years (QALYs) associated with four influenza and PPSV23 vaccination strategies among the elderly in Beijing. The strategies were as follows: (1) no vaccination; (2) only flu vaccine for people ≥ 60 years old; (3) flu vaccine for people ≥ 60 years old and PPSV23 for people ≥ 65 years old; and (4) dual influenza vaccines and PPSV23 for people ≥ 60 years old. Incremental costs and QALYs were quantified to determine the optimal option. If dominant strategies emerged, the Chinese gross domestic product per capita in 2021 (80,976 CNY) was used as the willingness-to-pay (WTP) threshold to covert QALYs into the monetary equivalent. (3) Results: The current program saved costs and increased QALYs compared to no vaccination or flu vaccine-only strategies. However, extending free PPSV23 to people ≥ 60 years old saved 0.35 CNY additionally while increasing QALYs marginally compared with the current policy. Results were robust in all sensitivity analyses. (4) Conclusion: Beijing's current dual influenza and pneumococcal vaccination program was cost-effective among the elderly compared with the preceding policies of no vaccination and flu-only immunization programs. However, the program can further save money while enhancing the population health by extending PPSV23 to all people ≥ 60 years old.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Cost-utility analysis of the universal pneumococcal vaccination programme for older adults in Norway

The aim of this study was to establish whether the universal pneumococcal vaccination for older adults in Norway is likely to be cost-effective from the perspective of the health care provider. A decision tree model developed by the Public Health Agency of Sweden was adapted to the Norwegian setting. Two cohorts, consisting of 65-year-olds and 75-year-olds grouped into vaccinated and unvaccinated, were followed over a 5-year time horizon. In the base case, the 23-valent polysaccharide vaccine (PPV23) was used while the 13-valent pneumococcal conjugate vaccine (PCV13) was included in scenario analyses only. The costs and health benefits (measured in quality adjusted life years (QALY) gained) were compared in the two cohorts between the vaccinated and unvaccinated groups. The impact of indirect effects of the vaccine, such as herd immunity and serotype replacement, were not investigated. The relative importance of change in price was assessed by performing one-way sensitivity analyses. Under base-case assumptions, the programme for the 75-year-old cohort is expected to be dominant (cost-effective) from the health care perspective at the current maximal pharmacy retail price and at 75% vaccination coverage. In comparison, for the 65-year-old cohort the cost per QALY gained is approximately NOK 601,784 (EUR 61,281) under the base-case assumptions. A reduction in the cost of the vaccine to one quarter of its current level also brings the cost per QALY gained within the acceptable ranges in a Norwegian context for both the 65- and 75-year-old cohorts. There is no exact cost-effectiveness threshold in Norway. However, introducing a vaccination programme against pneumococcal disease for 65-year-olds in Norway is likely to fall within the acceptable range while for the 75-year-old cohort the universal programme appears to be dominant (cost-effective).

Construction and protective efficacy of a novel Streptococcus pneumoniae fusion protein vaccine NanAT1-TufT1-PlyD4

During the past decades, with the implementation of pneumococcal polysaccharide vaccine (PPV) and pneumococcal conjugate vaccines (PCVs), a dramatic reduction in vaccine type diseases and transmissions has occurred. However, it is necessary to develop a less expensive, serotype-independent pneumococcal vaccine due to the emergence of nonvaccine-type pneumococcal diseases and the limited effect of vaccines on colonization. As next-generation vaccines, conserved proteins, such as neuraminidase A (NanA), elongation factor Tu (Tuf), and pneumolysin (Ply), are promising targets against pneumococcal infections. Here, we designed and constructed a novel fusion protein, NanAT1-TufT1-PlyD4, using the structural and functional domains of full-length NanA, Tuf and Ply proteins with suitable linkers based on bioinformatics analysis and molecular cloning technology. Then, we tested whether the protein protected against focal and lethal pneumococcal infections and examined its potential protective mechanisms. The fusion protein NanAT1-TufT1-PlyD4 consists of 627 amino acids, which exhibits a relatively high level of thermostability, high stability, solubility and a high antigenic index without allergenicity. The purified fusion protein was used to subcutaneously immunize C57BL/6 mice, and NanAT1-TufT1-PlyD4 induced a strong and significant humoral immune response. The anti-NanAT1-TufT1-PlyD4 specific IgG antibody assays increased after the first immunization and reached the highest value at the 35th day. The results from in vitro experiments showed that anti-NanAT1-TufT1-PlyD4 antisera could inhibit the adhesion of Streptococcus pneumoniae (S. pneumoniae) to A549 cells. In addition, immunization with NanAT1-TufT1-PlyD4 significantly reduced S. pneumoniae colonization in the lung and decreased the damage to the lung tissues induced by S. pneumoniae infection. After challenge with a lethal dose of serotype 3 (NC_WCSUH32403), a better protection effect was observed with NanAT1-TufT1-PlyD4-immunized mice than with the separate full-length proteins and the adjuvant control; the survival rate was 50%, which met the standard of the marketed vaccine. Moreover, we showed that the humoral immune response and the Th1, Th2 and Th17-cellular immune pathways are involved in the immune protection of NanAT1-TufT1-PlyD4 to the host. Collectively, our results support that the novel fusion protein NanAT1-TufT1-PlyD4 exhibits extensive immune stimulation and is effective against pneumococcal challenges, and these properties are partially attributed to humoral and cellular-mediated immune responses.

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.

Real-world effectiveness of pneumococcal vaccination in older adults: Cohort study using the UK Clinical Practice Research Datalink

BACKGROUND

The 23-valent pneumococcal polysaccharide vaccine (PPV23) is recommended for UK older adults, but how age moderates effectiveness is unclear.

METHODS

Three annual cohorts of primary-care patients aged≥65y from the Clinical Practice Research Datalink selected from 2003-5 created a natural experiment (n = 324,804), reflecting the staged introduction of the vaccine. The outcome was symptoms consistent with community-acquired pneumococcal pneumonia (CAP) requiring antibiotics or hospitalisation. We used the prior event rate ratio (PERR) approach to address bias from unmeasured confounders.

RESULTS

Vaccinated patients had higher rates of CAP in the year before vaccination than their controls, indicating the potential for confounding bias. After adjustment for confounding using the prior event rate ratio (PERR) method, PPV23 was estimated to be effective against CAP for two years after vaccination in all age sub-groups with hazard ratios (95% confidence intervals) of 0.86 (0.80 to 0.93), 0.74 (0.65 to 0.85) and 0.65 (0.57 to 0.74) in patients aged 65-74, 75-79 and 80+ respectively in the 2005 cohort. Age moderated the effect of vaccination with predicted risk reductions of 8% at 65y and 29% at 80y.

CONCLUSIONS

PPV23 is moderately effective at reducing CAP among UK patients aged≥65y, in the two years after vaccination. Vaccine effectiveness is maintained, and may increase, in the oldest age groups in step with increasing susceptibility to CAP.

Protocol for a phase IV double-blind randomised controlled trial to investigate the effect of the 13-valent pneumococcal conjugate vaccine and the 23-valent pneumococcal polysaccharide vaccine on pneumococcal colonisation using the experimental human pneumococcal challenge model in healthy adults (PREVENTING PNEUMO 2)

INTRODUCTION

Despite widely available vaccinations, Streptococcus pneumoniae (SPN) remains a major cause of morbidity and mortality worldwide, causing community-acquired pneumonia, meningitis, otitis media, sinusitis and bacteraemia. Here, we summarise an ethically approved protocol for a double-blind, randomised controlled trial investigating the effect of the 13-valent pneumococcal conjugate vaccine (PCV13) and the 23-valent pneumococcal polysaccharide vaccine (PPV23) on pneumococcal nasopharyngeal colonisation acquisition, density and duration using experimental human pneumococcal challenge (EHPC).

METHODS AND ANALYSIS

Healthy adult participants aged 18-50 years will be randomised to receive PCV13, PPV23 or placebo and then undergo one or two EHPCs involving intranasal administration of SPN at 1-month post-vaccination with serotype 3 (SPN3) and 6 months with serotype 6B (SPN6B). Participants randomised to PCV13 and placebo will also be randomised to one of two clinically relevant SPN3 strains from distinct lineages within clonal complex 180, clades Ia and II, creating five study groups. Following inoculation, participants will be seen on days 2, 7, 14 and 23. During the follow-up period, we will monitor safety, colonisation status, density and duration, immune responses and antigenuria. The primary outcome of the study is comparing the rate of SPN3 acquisition between the vaccinated (PCV13 or PPV23) and unvaccinated (placebo) groups as defined by classical culture. Density and duration of colonisation, comparison of acquisition rates using molecular methods and evaluation of the above measurements for individual SPN3 clades and SPN6B form the secondary objectives. Furthermore, we will explore the immune responses associated with these vaccines, their effect on colonisation and the relationship between colonisation and urinary pneumococcal antigen detection.

ETHICS AND DISSEMINATION

The study is approved by the NHS Research and Ethics Committee (Reference: 20/NW/0097) and by the Medicines and Healthcare products Regulatory Agency (Reference: CTA 25753/0001/001-0001). Findings will be published in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

ISRCTN15728847, NCT04974294.

Vaccination of older adults: Influenza, pneumococcal disease, herpes zoster, COVID-19 and beyond

Preserving good health in old age is of utmost importance to alleviate societal, economic and health care-related challenges caused by an aging society. The prevalence and severity of many infectious diseases is higher in older adults, and in addition to the acute disease, long-term sequelae, such as exacerbation of underlying chronic disease, onset of frailty or increased long-term care dependency, are frequent. Prevention of infections e.g. by vaccination is therefore an important measure to ensure healthy aging and preserve quality of life. Several vaccines are specifically recommended for older adults in many countries, and in the current SARS-CoV-2 pandemic older adults were among the first target groups for vaccination due to their high risk for severe disease. This review highlights clinical data on the influenza, Streptococcus pneumoniae and herpes zoster vaccines, summarizes recent developments to improve vaccine efficacy, such as the use of adjuvants or higher antigen dose for influenza, and gives an overview of SARS-CoV-2 vaccine development for older adults. Substantial research is ongoing to further improve vaccines, e.g. by developing universal influenza and pneumococcal vaccines to overcome the limitations of the current strain-specific vaccines, and to develop novel vaccines against pathogens, which cause considerable morbidity and mortality in older adults, but for which no vaccines are currently available. In addition, we need to improve uptake of the existing vaccines and increase awareness for life-long vaccination in order to provide optimal protection for the vulnerable older age group.

Effectiveness of 23-Valent Pneumococcal Polysaccharide Vaccine Against Pneumococcal Diseases Among the Elderly Aged 60 Years or Older: A Matched Test Negative Case-Control Study in Shanghai, China

Background:Streptococcus pneumoniae infection among adults, especially in adults over 60 years old in China results in a large number of hospitalizations and a substantial financial burden. This study assessed the vaccine effectiveness (VE) of 23-valent pneumococcal polysaccharide vaccine (PPV23) against pneumococcal diseases among the elderly aged 60 years or older in Shanghai, China.

Methods: We conducted a test-negative case–control study among the elderly aged 60 years or older who sought care at hospitals in 13 districts of Shanghai from September 14, 2013 to August 31, 2019. A case was defined as pneumococcal disease and testing positive for Streptococcus pneumoniae. Controls had symptoms congruent with pneumococcal disease but were negative for Streptococcus pneumoniae. We conducted 1:2 matching by gender, age, hospital and admission date. Vaccination status was verified from the immunization system database. VE was calculated with conditional logistic regression according to the formula (1–OR) ×100%.

Results: Overall, 603 adults aged 60 years or older with pneumococcal disease and positive for Streptococcus pneumoniae were included as cases, and 19.6% (118 persons) had a recorded PPV23 vaccination. The controls included 1,206 adults, whose vaccination rate was 23.8% (287 persons). The VE against pneumococcal diseases among the whole population was 24% (95% CI: 2%, 40%) and among women 44% (95% CI: 6%, 67%). After adjusting for multiple variables, the effectiveness of PPV23 against pneumococcal diseases was still statistically significant with VE for all of 25% (95% CI: 3%, 42%) and VE for women of 49% (95% CI: 11%, 71%).

Conclusion: PPV23 was effective against pneumococcal diseases in adults aged 60 years or older in Shanghai, China. Its relatively high effectiveness among women warrants this group to be particularly targeted for vaccination, with further research on why vaccination effectiveness is less among men.

The incidence of lower respiratory tract infections and pneumococcal vaccination status in adults in flemish primary care

Pneumococcal vaccination coverage of adults at risk for pneumococcal disease is below recommended levels. There is no observational data on pneumococcal vaccination and the incidence of lower respiratory tract infections in a general adult population. The current study had the objective to explore the incidence of lower respiratory tract infections and the pneumococcal vaccine coverage in function of age, influenza vaccination status and risk status, in Flanders, Belgium. We used data from Intego, ageneral practice-based morbidity registration network in Flanders (Belgium). We gathered data on pneumococcal vaccinations, influenza vaccination (in 2014) and ICPC2-coded diagnoses of pneumonia and acute bronchitis (2015). First, we divided the population into three groups along the risk status for developing apneumococcal infection according to the recommendations for pneumococcal vaccination in adults by the Belgian High Council of Health. 28.6% from our total adult study population are considered the target group for vaccination. Second, we found that the average pneumococcal vaccination coverage in this targeted population was 18.7%. Third, we found asignificantly higher incidence of LRTI in patients previously vaccinated against pneumococcal disease and/or influenza across the majority of subgroups. Pneumococcal vaccination coverage in Flanders is quantitatively low but observed to be qualitatively high in terms of reaching the most at risk population. Our findings are likely to be highly relevant to addressing future vaccination strategies in Flanders.

Effectiveness of Pneumococcal Vaccination Against Hospitalized Pneumococcal Pneumonia in Older Adults: A Prospective, Test-Negative Study

BACKGROUND

Despite use of the 13-valent pneumococcal conjugate vaccine (PCV13) and 23-valent pneumococcal polysaccharide vaccine (PPSV23) over the last decade, the disease burden of pneumococcal pneumonia is still high. We evaluated the field effectiveness of PCV13, PPSV23, and sequential vaccination against pneumococcal pneumonia in older adults.

METHODS

This prospective multicenter study was conducted in adults aged ≥ 65 years with hospitalized community-acquired pneumonia (CAP) between September 2015 and August 2017. The case-control test-negative design was used to estimate vaccine effectiveness (VE) against pneumococcal CAP.

RESULTS

Of 1,525 cases with hospitalized CAP, 167 (11.0%) were identified as pneumococcal CAP. In the elderly aged ≥65 years, the adjusted VE of pneumococcal vaccines against pneumococcal CAP was statistically insignificant: 40.0% (95% CI -10.8% to 67.5%) for PCV13 and 11.0% (95% CI, -26.4% to 37.3%) for PPSV23. However, in the younger subgroup (aged 65-74 years), sequential PCV13/PPSV23 vaccination showed the highest adjusted VE of 80.3% (95% CI 15.9% to 95.4%), followed by single-dose PCV13 (adjusted VE 66.4%; 95% CI 0.8% to 88.6%) and PPSV23 (adjusted VE 18.5%; 95% CI -38.6% to 52.0%).

CONCLUSIONS

Sequential PCV13/PPSV23 vaccination is most effective for preventing pneumococcal CAP among the elderly aged 65-74 years.

Community-acquired pneumonia

Community-acquired pneumonia is not usually considered a high-priority problem by the public, although it is responsible for substantial mortality, with a third of patients dying within 1 year after being discharged from hospital for pneumoniae. Although up to 18% of patients with community-acquired pneumonia who were hospitalised (admitted to hospital and treated there) have at least one risk factor for immunosuppression worldwide, strong evidence on community-acquired pneumonia management in this population is scarce. Several features of clinical management for community-acquired pneumonia should be addressed to reduce mortality, morbidity, and complications related to community-acquired pneumonia in patients who are immunocompetent and patients who are immunocompromised. These features include rapid diagnosis, microbiological investigation, prevention and management of complications (eg, respiratory failure, sepsis, and multiorgan failure), empirical antibiotic therapy in accordance with patient's risk factors and local microbiological epidemiology, individualised antibiotic therapy according to microbiological data, appropriate outcomes for therapeutic switch from parenteral to oral antibiotics, discharge planning, and long-term follow-up. This Seminar offers an updated view on community-acquired pneumonia in adults, with suggestions for clinical and translational research.

Is there a need for pneumococcal vaccination programs for the homeless to prevent invasive pneumococcal disease?

INTRODUCTION

Homeless are a vulnerable segment of society at risk for infections. Invasive pneumococcal disease (IPD) infections are increasingly identified in homeless as a major contributor of morbidity and mortality. Very few countries have recommended pneumococcal vaccination programs for the homeless.

AREAS COVERED

A literature review of IPD in the homeless from 1980 to 2020 in PubMed and Scopus using terms, 'homeless,' and 'homelessness,' and after 'chronic' or 'transitory' homeless was conducted. Gray literature from the CDC, WHO and major governmental agencies/organizations were included. Terms for IPD eligible for inclusion in the database search included 'pneumococcal disease,' 'invasive pneumococcal disease,' 'Streptococcus pneumoniae.' This included outbreaks of pneumococcal disease in the homeless, clinical characteristics associated with pneumococcal disease in the homeless, pneumococcal vaccines and vaccination recommendations for the homeless.

EXPERT OPINION

Homeless populations are at increased risk for IPD in comparison to the general population. This is due to clinical conditions experienced by the homeless including alcoholism and cigarette smoking. In addition, a collection of specific pneumococcal serotypes are associated with IPD in this group. Pneumococcal vaccine programs aimed at this population would likely decrease the incidence of IPD for this group and contribute to better overall health for the homeless.

Pneumococcal vaccine uptake and vaccine effectiveness in older adults with invasive pneumococcal disease in Germany: A retrospective cohort study

BACKGROUND

Invasive pneumococcal disease (IPD) in people ≥60 years old is on the rise in Germany. There has been a recommendation for pneumococcal vaccination in this age group since 1998.

METHODS

We determined the vaccination status of people ≥60 years old with IPD in Germany. We assessed vaccine effectiveness (VE) of the recommended 23-valent polysaccharide vaccine (PPV23) against IPD using the indirect cohort method.

RESULTS

The rate of pneumococcal vaccination in older adults with IPD is low, 26%, with only 16% of people receiving a pneumococcal vaccine within five years of the IPD episode. Age- and gender- adjusted vaccine effectiveness (VE) for PPV23 was 37% (95% confidence interval 12% - 55%). For people vaccinated with PPV23 less than two years prior to IPD, VE was -20% (-131% - 34%), between two and four years prior to IPD, VE was 56% (20% - 76%), and 47% (17% - 63%) for those vaccinated ≥5 five years ago. Excluding serotype 3, overall VE for the remaining serotypes in PPV23 was 63% (49% - 74%). For people receiving PPV23 within the past two years, VE against all serotypes except 3 was 49% (12% - 71%); for people vaccinated between two and four years prior to IPD 66% (37% - 82%); for those vaccinated ≥five years ago, 69% (50% - 81%). VE of PPV23 against serotype 3 IPD only was -110% (-198% - -47%).

CONCLUSIONS

To reduce IPD in older adults in Germany, we must increase the rate of pneumococcal vaccine uptake. For 22/23 serotypes, PPV23 was effective. Serotype 3 remains a major problem.

FUNDING

This work was supported by an investigator-initiated research grant from Pfizer.

The impact of childhood 13-valent pneumococcal conjugate vaccination on overall invasive pneumococcal disease, including the oldest old

Objectives: Our aim was to compare serotype distribution in invasive pneumococcal disease (IPD) in the Belgian population before and after introduction of the 13-valent conjugte vaccine (PCV13) in the national childhood vaccination schedule.Methods: Serotyping was performed on 12,534 pleural fluid and bacteraemic Streptococcus pneumoniae isolates sent to the National Reference Centre. We compared the distribution of serotypes (ST)/serogroups (SG) between the periods before (2007-2010) and after (2012-2015) the introduction of PCV13, in children and adults of different age groups, including older individuals (65-84 and ≥85 years).Results: The introduction of PCV13 in the childhood immunization program resulted in a reduction of 16% of all IPD-isolates. The prevalence of PCV13-SG decreased in all age groups: from 81% to 53% (p < 0.0001) in children <18 years, and from 69% to 53% (p < 0.0001) in individuals aged 18-64. This effect was also observed in age groups 65-84 (64% to 50%, p < 0.0001) and ≥85 years (63% to 47%; p < 0.0001). The proportion of IPD cases caused by non-PCV13 SG increased from 31% to 49% between the two periods, indicating replacement with non-vaccine SG. The coverage rate for the 23-valent polysaccharide vaccine (PPV23) in all age groups remains as high as 89% for the total group.Conclusion: After introduction of PCV13, a reduction of PCV13-serotypes occurred in IPD in all age groups. This supports the rationale to combine the effect of PCV13 with the broader coverage of PPV23 as a vaccination strategy for adults.

Effectiveness of 23-Valent Pneumococcal Polysaccharide Vaccine against Invasive Pneumococcal Disease in Adults, Japan, 2013-2017

The decline in the proportion of pneumococcal conjugate vaccine (PCV)–covered serotypes among adult invasive pneumococcal disease (IPD) patients might change the overall effectiveness of the 23-valent pneumococcal polysaccharide vaccine (PPSV23) because its effectiveness differs according to serotype. Using the indirect cohort method, we calculated the effectiveness of PPSV23 against IPD among adults in Japan to assess the impact of the national pediatric PCV program. Clinical and epidemiologic information and pneumococcal isolates were collected from IPD patients >20 years of age through enhanced IPD surveillance during April 2013–December 2017. Adjusted effectiveness against PPSV23-serotype IPD was 42.2%. Despite a substantial decline in the proportion of 13-valent PCV serotypes during the study period (45% to 31%), the change in effectiveness for PPSV23-serotype IPD was limited (47.1% to 39.3%) and only marginal in the elderly population (39.9% to 39.4%). The pediatric PCV program had limited impact on PPSV23 effectiveness against IPD in adults.

Multiple comorbidities increase the risk of death from invasive pneumococcal disease under the age of 65 years

INTRODUCTION

Risk factors for death from invasive pneumococcal disease (IPD) have not been clearly established in patients aged under 65 years. We aimed to evaluate contributions of host and bacterial factors to the risk of death from IPD in patients aged under 65 years in Japan.

METHODS

In this prospective, observational, multicenter cohort study, patients with IPD (n = 581) aged 6-64 years were enrolled between 2010 and 2017. We investigated the role of host and bacterial factors in 28-day mortality.

RESULTS

The mortality rate increased from 3.4% to 6.2% in patients aged 6-44 years to 15.5%-19.5% in those aged 45-64 years. Multivariable analysis identified the following risk factors for mortality: age 45-64 years (hazard ratio [HR], 3.4; 95% confidence interval [CI], 1.6-6.8, p = 0.001), bacteremia with unknown focus (HR, 2.0; 95% CI, 1.1-3.7, p = 0.024), meningitis (HR, 2.1; 95% CI, 1.1-4.0, p = 0.019), underlying multiple non-immunocompromising conditions (HR, 2.6; 95% CI, 1.1-7.4, p = 0.023), and immunocompromising conditions related to malignancy (HR, 2.4; 95% CI, 1.0-5.2, p = 0.039). Pneumococcal serotype was not associated with poor outcomes.

CONCLUSIONS

Host factors, including age of 45-64 years and underlying multiple non-immunocompromising conditions, are important for the prognosis of IPD. Our results will contribute to the development of targeted pneumococcal vaccination strategies in Japan.

Constrained Optimization for Pneumococcal Vaccination in Brazil

OBJECTIVES

To identify the most cost-efficient combination of pneumococcal vaccines in infants and aging adults for a 10-year period in Brazil.

METHODS

Constrained optimization (CO) prioritized 9 pneumococcal vaccine regimens according to their gain in quality-adjusted life-years (QALYs) and their related costs over a prespecified time horizon with defined constraints for 2 age groups, infants and aging adults. The analysis starts from the current universal infant vaccination of pneumococcal non-typeable Haemophilus influenzae protein D conjugate vaccine (PHiD-CV), 2 primary and 1 booster dose at 2, 4, and 12 months, respectively. Key constraints are the fixed annual vaccine budget increase and the relative return on investment (ROI_R) per regimen, which must be > 1, the reference intervention being the current vaccination strategy in infants and the most cost-efficient one in aging adults.

RESULTS

The CO analysis including all the constraints indicates that over 10 years the maximum extra health gain is 126 194 QALYs for an extra budget of $974 million Brazilian reals (ROI_R = 1.15). Results could be improved with a higher proportion of the at-risk population in aging adults, less herd effect, and better QALY scores.

CONCLUSION

The study shows that with 4 constraints on budget, time horizon, vaccine coverage, and cost efficiency, a CO analysis could identify the most cost-efficient overall pneumococcal vaccination strategy for Brazil, allowing for limited vaccine budget increase while obtaining appropriate health gain.

Cost-effectiveness of dual influenza and pneumococcal vaccination among the elderly in Shenzhen, China

OBJECTIVE

To assess the cost-effectiveness of dual influenza and pneumococcal vaccination for the elderly in Shenzhen, China.

METHODS

A Markov state-transition model with a weekly cycle was developed to compare the outcomes of dual influenza and pneumococcal vaccination for the prevention of influenza and pneumococcal infections compared with no vaccination among 70-74 years old people in Shenzhen over 5 years. The model allowed seasonal variation of influenza activity. We calculated the incremental cost-effectiveness ratio (ICER) with costs and quality-adjusted life years (QALYs) discounted at 5% annually from the societal perspective. The impact of parameter uncertainty on the results was examined using one-way and probabilistic sensitivity analyses (PSA).

RESULTS

In the base case, dual vaccination prevented 5042 influenza infections, 26 IPD cases, 3 disabilities, 34 deaths, and cost US$7.1 per person while resulting in a net gain of 0.0026 QALYs compared with no vaccination. Using once the Chinese gross domestic product per capita in 2019 (US$10,289) as the willingness-to-pay threshold, dual vaccination was cost-effective with an ICER of US$2699 per QALY gained. One-way sensitivity analyses showed that the ICER was relatively sensitive to changes in influenza attack rates and influenza vaccine effectiveness. Based on the results of PSA with 1000 Monte Carlo simulations, receiving both vaccines was cost-effective in 100% of the repetitions.

CONCLUSION

The current study provides evidence that dual influenza and pneumococcal vaccination is a cost-effective disease prevention strategy for the elderly in Shenzhen, China.

Distribution and Variation of Serotypes and Pneumococcal Surface Protein A Clades of Streptococcus pneumoniae Strains Isolated From Adult Patients With Invasive Pneumococcal Disease in Japan

Pneumococcal surface protein A (PspA) is a surface protein of Streptococcus pneumoniae that may be a candidate antigen for new pneumococcal vaccines. This study investigates the distribution of PspA clades of the causative strains of adult invasive pneumococcal disease (IPD) in Japan. Of the 1,939 strains isolated from cases of adult IPD during 2014–2019, the PspA clades of 1,932 (99.6%) strains were determined, and no pspA was detected in the remaining 7 strains (0.4%). PspA clades 1–6 were detected in 786 (40.5%), 291 (15.0%), 443 (22.8%), 369 (19.0%), 33 (1.7%), and 6 (0.3%) strains, respectively. New PspA clades (0.2%) were identified in two non-typeable and two serotype 35B pneumococci. The proportions of clade 1 and clade 2 showed significantly decreased and increased trends, respectively. Furthermore, the PspA clade of pneumococcal strains was partially serotype- and sequence type-dependent. The majority of strains belonging to serotypes contained in both the 13-valent pneumococcal conjugate vaccine (PCV13) and the 23-valent pneumococcal polysaccharide vaccine (PPSV23) belonged to PspA clades 1 or 3. In contrast, the distribution of clades in non-vaccine serotypes was wider than that of vaccine serotype pneumococci. Our findings demonstrate that almost all pneumococcal strains from adult IPD express PspA clades 1–4, especially for non-vaccine serotypes. These results may be useful for the development of a new pneumococcal vaccine with PspA.

Evaluation of the decision-making process underlying the initial off-label use of vaccines: a scoping review protocol

INTRODUCTION

Vaccination has become a central part of public health prevention. Vaccines are introduced after licensure by national regulatory authorities, whereas recommendations for use of licensed vaccines are made by national or international advisory committees and may include off-label use. The methodological and decision-making processes that are used to assess novel initial off-label vaccine use are unclear. This review aims to examine the off-label assessment processes to map evidence and concepts used in the decision-making process and present a common approach between all recommendations and specifics of each decision.

METHODS AND ANALYSIS

The methodological framework described at the Joanna Briggs Institute will be applied to this scoping review. A search strategy was developed, in collaboration with an experienced senior health research librarian, by combining Mesgarpour's highly sensitive search strategies. Peer-reviewed and grey literature will be systematically identified using PubMed, Medline and EMBASE; governmental agency and pharmaceutical websites; and search engines, such as Google Scholar. Reports and studies on off-label vaccine use in public health will be included. Screening will be independently undertaken by two reviewers. Data will be extracted using a standard form. Results will be narratively summarised to highlight relevant findings and guide the development of an analytical framework for off-label vaccination recommendations.

ETHICS AND DISSEMINATION

This research does not require ethical approval. This scoping review will provide decision-making elements and a synthesis of knowledge on vaccines off-label use. Findings will be relevant to decision-makers/advisory committees and public health. These will be disseminated through peer-reviewed articles and conferences.

Efficacy and effectiveness of a 23-valent polysaccharide vaccine against invasive and noninvasive pneumococcal disease and related outcomes: a review of available evidence

Introduction: Routine pneumococcal vaccination for adults aged ≥60 or ≥65 years and those with underlying at-risk and high-risk conditions is recommended in many countries. However, studies estimating the effectiveness of 23-valent pneumococcal polysaccharide vaccine (PPSV23) have revealed mixed results, partly due to variability in study design and endpoints used to assess outcomes.Areas covered: The authors conducted a literature review of independently randomized trials and real-world studies published from 2010 to 2020 that assessed the effectiveness and efficacy of PPSV23 against vaccine-type or any-serotype invasive and noninvasive pneumococcal disease in adults aged ≥60 years. The authors also evaluated differences in study design that may contribute to the heterogeneity of available evidence.Expert opinion: Policy decisions regarding the inclusion of vaccines into national immunization plans should consider study quality and limitations. This review shows that PPSV23 is effective against vaccine-type invasive pneumococcal disease and vaccine-type pneumococcal pneumonia and can lower the burden of vaccine-type pneumococcal pneumonia. PPSV23-conferred protection may be lower in adults aged ≥75 years, those with certain underlying conditions, and individuals who were vaccinated >5 years before disease onset. This is an important finding that supports the benefit of PPSV23 vaccination for older adults.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Cost-effectiveness of pneumococcal vaccines among adults over 50 years old in low- and middle-income countries: a systematic review

INTRODUCTION

This systematic review aims to provide a critical summary of economic evaluations of pneumococcal vaccines for adults aged 50 years or older in low- and middle-income countries (LMICs): a 23-valent polysaccharide vaccine (PPSV23), and a 13-valent conjugated vaccine (PCV13).

AREAS COVERED

We systematically searched for studies published until October2020 in PubMed and Web of Science. Searching strategies in this literature review were done using various combinations of terms related to 'economic evaluation or cost-effectiveness or cost-benefit or cost-utility,' 'pneumococcal or PPSV or PCV or PPV,' and 'vaccine or vaccination or immunization' in all fields. To be included, each study had to meet our inclusion criteria. Two authors reviewed and extracted studies. From 1,711 records, we included 18 studies for this review. All 18 studies were cost-effectiveness analysis. Compared with no vaccination, either PPSV23 or PCV13 was economically favorable, highly cost-effective, and in many cases, cost-saving for older adults. Studies compared one vaccination (PPSV23 or PCV13) over another and had different findings.

EXPERT OPINION

While all studies recommended either PPSV23 or PCV13 for older adults in LMICs, substantial questions about potential bias in studies and whether conclusions hold after including the impact of indirect protection.

Application of the screening and indirect cohort methods to evaluate the effectiveness of pneumococcal vaccination program in adults 75 years and older in Taiwan

Background

The Taiwanese national 23-valent pneumococcal polysaccharide vaccine (PPV23) program in adults ≥75 years of age and the 13-valent pneumococcal conjugate vaccine (PCV13) program for children were implemented in 2008 and 2013, respectively. In this study we evaluated PPV23 vaccine effectiveness (PPV23VE) in the elderly, with regard to both direct protection from the vaccine itself and the indirect protection conferred by PCV13 immunization in children.

Methods

The incidence of invasive pneumococcal disease (IPD) in Taiwan from July 2008 to June 2016 was collected from IPD surveillance data. A comparison of IPD incidence with a nationwide vaccination registry allowed an estimation of PPV23VE by the screening and indirect cohort methods.

Results

The incidence of IPD in adults ≥75 years of age ranged from 13.9 per 100,000 inhabitants during the period July 2008–June 2013 to 10.4 per 100,000 inhabitants between July 2013 and June 2016 (relative risk [RR]: 0.75; 95% confidence interval [95% CI]: 0.67–0.85). According to the screening method, PPV23VE against death within 30 days of IPD onset, all IPD, and PPV23-serotype IPD was 32.5% (95% CI: 17.5–44.7%), 33.9% (95% CI: 25.2–41.5%) and 43.4% (95% CI: 34.4–51.2%), respectively. PPV23VE with the indirect cohort method was 39.0% (95% CI: 15.5–55.9%) for all PPV23 serotypes and 71.5% (95% CI: 44.2–85.4%) for 11 serotypes included in PPV23 but not in PCV13. During the period July 2008–June 2012, PPV23VE against PPV23-serotype IPD was 55.1% (95% CI: 27.2–72.3%).

Conclusions

PPV23 is able to prevent IPD and 30-day fatality in adults 75 years of age and older due to a combination of direct effects from PPV23 and indirect effects from PCV13. It might confer higher protection against PPV23-serotype IPD before the introduction of PCV13 program in children.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-020-05721-0.

Vaccination pattern of the 23-valent pneumococcal polysaccharide vaccine (PPV23) in Hangzhou, China: a coverage and adverse events following immunization of different age groups

Background: 23-valent pneumococcal polysaccharide vaccine (PPSV23) has been used to prevent pneumococcal disease, and PPSV23 became available in 2003 in Hangzhou, China as a private-sector, vaccinee-chosen vaccine. No national guidelines for PPSV23 have been developed. We analyzed PPSV23 coverage and utilization in Hangzhou to determine patterns of PPSV23 use and the occurrence of adverse events following immunization (AEFI) in Hangzhou. Materials and Methods: Individuals over 2 years of age in Hangzhou were included. Vaccination data during 2006-2017 was retrieved from Hangzhou's Immunization Information System (HZIIS). We used descriptive epidemiological methods to determine PPSV23 usage patterns and AEFI occurrence. Results: In 2017, there were 9,027,973 persons above 2 years of age with the coverage of PPSV23 of 2.98%. The coverage of PPSV23 among elders ranged from 0.17% to 0.69%, and the overall coverage was higher in urban areas (3.70%) than in rural (3.34%) and suburban areas (2.16%). 93.45% of 268957 recipients were vaccinated with PPSV23 at 2-4 years of age. 394 AEFI of PPSV23 cases were reported to the Chinese national adverse event following immunization information system (CNAEFIS) during 2008-2017, with the reporting rate of 140.39 per 100,000 doses. Conclusion: Persons in Hangzhou had overall low PPSV23 vaccination coverage especially for adults. Most of PPSV23 were used in children, while the proportion of the old population over 60 years slightly increased over year. PPSV23 was safe with a low reported AEFI rate, which was a little higher for children than for the elderly (over 60 years).

Current situation and need for prevention of invasive pneumococcal disease and pneumococcal pneumonia in 6- to 64-year-olds in Japan

We conducted a systematic review of the literature to evaluate the reported epidemiology and burden of invasive pneumococcal disease (IPD) and pneumococcal pneumonia (PP) among children and adults aged 6-64 years in Japan. Studies published from Japan between September 2009 and September 2019 and indexed in the MEDLINE/PubMed or ICHUSHI databases were evaluated. A majority of the studies reported overlapping age ranges, including children aged <6 years and adults aged >64 years. According to the national surveillance data, 19% of the IPD cases were patients aged 5-59 years, and an increasing trend in IPD cases was reported from 2013 to 2017. Comorbidities were consistent with those reported by the Advisory Committee on Immunization Practices. Deaths from IPD appeared to increase nearly 3-fold between 2013 and 2017. Overall, both 13-valent pneumococcal conjugate vaccine (PCV13) and 23-valent pneumococcal polysaccharide vaccine (PPSV23) coverage was higher for IPD compared with PP. All the serotypes known to be prominent in Japan were also identified as common serotypes (3, 6A, 19A: PCV13 serotypes; 12F: outbreak serotype; 15A, 35B: drug-resistant serotypes). This systematic literature review suggests a substantial burden of IPD and PP in Japanese children and adults aged 6-64 years. The burden of comorbidities, hospitalizations, and mortality was particularly high among adults. Concerted pneumococcal vaccination strategies may help to reduce the incidence and burden of IPD and PP in this large proportion of the Japanese population.

Prevalence of influenza and pneumococcal vaccination in chronic obstructive pulmonary disease patients in association with the occurrence of acute exacerbations

Background

Based on current evidence, vaccination is recommended against the influenza virus and pneumococcus to avoid serious acute exacerbations in patients with chronic obstructive pulmonary disease (COPD), but the rate of their vaccination coverage is still suboptimal. To determine the prevalence and effectiveness of influenza and pneumococcal vaccination in COPD patients, and to prove its hypothetical association with the decreasing number of acute exacerbations.

Methods

We conducted a retrospective, population-based cohort study. Influenza and pneumococcal vaccination history were collected from 250 patients selected by simple random sampling from all COPD patients in Budapest at the Department of Pulmonary Rehabilitation of the National Koranyi Institute of Pulmonology between 01 January 2019 and 01 June 2019. Inclusion criteria were the following: age 40 years and diagnosis of COPD. Odds ratios (ORs) were evaluated based on the occurrence of acute exacerbations during the preceding year.

Results

The average age was 66.62 (±8.34) years, 67.30 (±8.54) for males, and 66.09 (±8.16) for females. Man:woman ratio: 43.6%:56.4% in total. Overall prevalence of influenza vaccination was 23.6%, and the pneumococcal vaccination rate was 10.8% among COPD patients. Influenza and pneumococcal vaccination showed a significant protective effect and reduced the occurrence of exacerbations in the following year, influenza vaccination OR: 2.11 (95% CI: 0.88-5.02), pneumococcal vaccination OR: 1.06 (95% CI: 0.84-1.34), when taking both vaccination: OR: 2.37 (95% CI: 1.39-4.08).

Conclusions

We found association between influenza and pneumococcal vaccination and the reduced risk of hospitalization due to exacerbations in the ensuing year. The prevalence of vaccination is significantly below the optimal level.

Smoking Cessation/Vaccinations

More than one-third of patients with chronic obstructive pulmonary disease (COPD) continue to smoke cigarettes despite knowing they have the disease. This behavior has a negative impact on prognosis and progression, as repeated injury enhances the pathobiological mechanisms responsible for the disease. A combination of counseling plus pharmacotherapy is the most effective cessation treatment of smokers with COPD, and varenicline seems to be the most effective pharmacologic intervention. Preventing exacerbations in patients with COPD is a major goal of treatment, and vaccination against influenza and pneumococcus is an effective preventive strategy to achieve this goal.

Impact of the 13-Valent Pneumococcal Conjugate Vaccine on the Incidence of All-cause Pneumonia in Adults Aged ≥60 Years: A Population-based, Retrospective Cohort Study

In this population-based study evaluating the effectiveness of the 13-valent pneumococcal conjugate vaccine (2012-2016) to prevent all-cause pneumonia in adults ≥60 years of age, we found significant, 0.63% absolute risk and 11.9% relative risk reductions on the 3-year (2014-2016) cumulative incidences of all-cause pneumonia after vaccination.

Cost-effectiveness of pneumococcal vaccination for elderly in Sweden

INTRODUCTION

The aim was to assess cost-effectiveness of including pneumococcal vaccination for elderly in a national vaccination programme in Sweden, comparing health-effects and costs of pneumococcal related diseases with a vaccination programme versus no vaccination.

METHOD

We used a single-cohort deterministic decision-tree model to simulate the current burden of pneumococcal disease in Sweden. The model accounted for invasive pneumococcal disease (IPD) and pneumonia caused by pneumococci. Costs included in the analysis were those incurred when treating pneumococcal disease, and acquisition and administration of the vaccine. Health effects were measured as quality-adjusted life years (QALY). The time-horizon was set to five years, both effects and costs were discounted by 3% annually. Health-effects and costs were accumulated over the time-horizon and used to create an incremental cost-effectiveness ratio. The 23-valent polysaccharide vaccine (PPV23) was used in the base-case analysis. The 13-valent pneumococcal conjugate vaccine PCV13 was included in sensitivity analyses.

RESULTS

A vaccination programme using PPV23 would reduce the burden of pneumococcal related disease significantly, both when vaccinating a 65-year-old cohort and a 75-year-old cohort. IPD would decrease by 30% in the 65-year-old cohort, and by 29% in the 75-year-old cohort. The corresponding figures for CAP (communicable acquired pneumonia) are 19% and 15%. The cost per gained QALY was estimated to EUR 94,000 for vaccinating 65-year-olds and EUR 29,500 for 75-year-olds. With one dose PCV13 given instead of PPV23, the cost per gained QALY would increase by around 400% for both cohorts. The results were robust in sensitivity analyses.

CONCLUSION

Introducing a vaccination programme against pneumococcal disease for 65-year-olds in Sweden is unlikely to be cost-effective, whereas it for 75 year-olds and using PPV23 can be considered good value for money. Our model indicates that vaccine price needs to be reduced by 55% for vaccination of 65-year-olds to be cost-effective, given a threshold of EUR 50,000.

Vaccines to Prevent Infectious Diseases in the Older Population: Immunological Challenges and Future Perspectives

Infectious diseases are a major cause for morbidity and mortality in the older population. Demographic changes will lead to increasing numbers of older persons over the next decades. Prevention of infections becomes increasingly important to ensure healthy aging for the individual, and to alleviate the socio-economic burden for societies. Undoubtedly, vaccines are the most efficient health care measure to prevent infections. Age-associated changes of the immune system are responsible for decreased immunogenicity and clinical efficacy of most currently used vaccines in older age. Efficacy of standard influenza vaccines is only 30-50% in the older population. Several approaches, such as higher antigen dose, use of MF59 as adjuvant and intradermal administration have been implemented in order to specifically target the aged immune system. The use of a 23-valent polysaccharide vaccine against Streptococcus pneumoniae has been amended by a 13-valent conjugated pneumococcal vaccine originally developed for young children several years ago to overcome at least some of the limitations of the T cell-independent polysaccharide antigens, but still is only approximately 50% protective against pneumonia. A live-attenuated vaccine against herpes zoster, which has been available for several years, demonstrated efficacy of 51% against herpes zoster and 67% against post-herpetic neuralgia. Protection was lower in the very old and decreased several years after vaccination. Recently, a recombinant vaccine containing the viral glycoprotein gE and the novel adjuvant AS01B has been licensed. Phase III studies demonstrated efficacy against herpes zoster of approx. 90% even in the oldest age groups after administration of two doses and many countries now recommend the preferential use of this vaccine. There are still many infectious diseases causing substantial morbidity in the older population, for which no vaccines are available so far. Extensive research is ongoing to develop vaccines against novel targets with several vaccine candidates already being clinically tested, which have the potential to substantially reduce health care costs and to save many lives. In addition to the development of novel and improved vaccines, which specifically target the aged immune system, it is also important to improve uptake of the existing vaccines in order to protect the vulnerable, older population.

A Systematic Review of Studies Published between 2016 and 2019 on the Effectiveness and Efficacy of Pneumococcal Vaccination on Pneumonia and Invasive Pneumococcal Disease in an Elderly Population

Adult vaccination is high on the agenda in many countries. Two different vaccines are available for the prevention of pneumococcal disease in adults: a 23-valent polysaccharide vaccine (PPV23), and a 13-valent conjugated vaccine (PCV13). The objective of this review is to update the evidence base for vaccine efficacy and effectiveness of PPV23 and PCV13 against invasive pneumococcal disease and pneumonia among an unselected elderly population. We systematically searched for clinical trials and observational studies published between January 1 2016 and April 17 2019 in Pubmed, Embase, Cinahl, Web of Science, Epistemonikos and Cochrane databases. Risk of bias was assessed using Cochrane Risk of Bias tool for and the Newcastle–Ottawa Scale. Results were stratified by vaccine type and outcome. We identified nine studies on PCV13 and six on PPV23. No new randomized clinical trials were identified. Due to different outcomes, it was not possible to do a meta-analysis. New high-quality observational studies indicate protective vaccine effectiveness for both vaccines against vaccine type pneumonia. Our estimates for the protective vaccine efficacy and effectiveness (VE) of PPV23 on pneumonia and pneumococcal pneumonia overlap with results from previously published reviews. Some of the results indicate that the effectiveness of the PPV23 is best in younger age groups, and that it decreases over time.

Development of Next Generation Streptococcus pneumoniae Vaccines Conferring Broad Protection

Streptococcus pneumoniae is a major pathogen causing pneumonia with over 2 million deaths annually, especially in young children and the elderly. To date, at least 98 different pneumococcal capsular serotypes have been identified. Currently, the vaccines for prevention of S. pneumoniae infections are the 23-valent pneumococcal polysaccharide-based vaccine (PPV23) and the pneumococcal conjugate vaccines (PCV10 and PCV13). These vaccines only cover some pneumococcal serotypes and are unable to protect against non-vaccine serotypes and unencapsulated S. pneumoniae. This has led to a rapid increase in antibiotic-resistant non-vaccine serotypes. Hence, there is an urgent need to develop new, effective, and affordable pneumococcal vaccines, which could cover a wide range of serotypes. This review discusses the new approaches to develop effective vaccines with broad serotype coverage as well as recent development of promising pneumococcal vaccines in clinical trials. New vaccine candidates are the inactivated whole-cell vaccine strain (Δpep27ΔcomD mutant) constructed by mutations of specific genes and several protein-based S. pneumoniae vaccines using conserved pneumococcal antigens, such as lipoprotein and surface-exposed protein (PspA). Among the vaccines in Phase 3 clinical trials are the pneumococcal conjugate vaccines, PCV-15 (V114) and 20vPnC. The inactivated whole-cell and several protein-based vaccines are either in Phase 1 or 2 trials. Furthermore, the recent progress of nanoparticles that play important roles as delivery systems and adjuvants to improve the performance, as well as the immunogenicity of the nanovaccines, are reviewed.

Community-Acquired Pneumonia. Spanish Society of Pulmonology and Thoracic Surgery (SEPAR) Guidelines. 2020 Update

The guidelines for community-acquired pneumonia, last published in 2010, have been updated to provide recommendations based on a critical summary of the latest literature to help health professionals make the best decisions in the care of immunocompetent adult patients. The methodology was based on 6 PICO questions (on etiological studies, assessment of severity and decision to hospitalize, antibiotic treatment and duration, and pneumococcal conjugate vaccination), agreed by consensus among a working group of pulmonologists and an expert in documentation science and methodology. A comprehensive review of the literature was performed for each PICO question, and these were evaluated in in-person meetings. The American Thoracic Society guidelines were published during the preparation of this paper, so the recommendations of this association were also evaluated. We concluded that the etiological source of the infection should be investigated in hospitalized patients who have suspected resistance or who fail to respond to treatment. Prognostic scales, such as PSI, CURB 65, and CRB65, are useful for assessing severity and the decision to hospitalize. Different antibiotic regimens are indicated, depending on the treatment setting - outpatient, hospital, or intensive care unit - and the resistance of PES microorganisms should be calculated. The minimum duration of antibiotic treatment should be 5 days, based on criteria of clinical stability. Finally, we reviewed the indication of the 13-valent conjugate vaccine in immunocompetent patients with risk factors and comorbidity.

Indirect costs of adult pneumococcal disease and the productivity-based rate of return to the 13-valent pneumococcal conjugate vaccine for adults in Turkey

Productivity benefits of health technologies are ignored in typical economic evaluations from a health payer’s perspective, risking undervaluation. We conduct a productivity-based cost-benefit analysis from a societal perspective and estimate indirect costs of adult pneumococcal disease, vaccination benefits from the adult 13-valent pneumococcal conjugate vaccine (PCV13 Adult), and rates of return to PCV13 Adult for a range of hypothetical vaccination costs. Our context is Turkey’s funding PCV13 for the elderly and for non-elderly adults with select comorbidities within the Ministry of Health’s National Immunization Program. We use a Markov model with one-year cycles. Indirect costs from death or disability equal the expected present discounted value of lifetime losses in the infected individual’s paid and unpaid work and in caregivers’ paid work. Vaccination benefits comprise averted indirect costs. Rates of return equal vaccination benefits divided by vaccination costs, minus one. Input parameters are from public data sources. We model comorbidities’ effects by scalar multiplication of the parameters of the general population. Indirect costs per treatment episode of inpatient community-acquired pneumonia (CAP), bacteremia, and meningitis – but not for outpatient CAP – approach or exceed Turkish per capita gross domestic product. Vaccination benefits equal $207.02 per vaccination in 2017 US dollars. The rate of return is positive for all hypothetical costs below this. Results are sensitive to herd effects from pediatric vaccination and vaccine efficacy rates. For a wide range of hypothetical vaccination costs, the rate of return compares favorably with those of other global development interventions with well-established strong investment cases.

Immunosenescence and human vaccine immune responses

The age-related dysregulation and decline of the immune system-collectively termed "immunosenescence"-has been generally associated with an increased susceptibility to infectious pathogens and poor vaccine responses in older adults. While numerous studies have reported on the clinical outcomes of infected or vaccinated individuals, our understanding of the mechanisms governing the onset of immunosenescence and its effects on adaptive immunity remains incomplete. Age-dependent differences in T and B lymphocyte populations and functions have been well-defined, yet studies that demonstrate direct associations between immune cell function and clinical outcomes in older individuals are lacking. Despite these knowledge gaps, research has progressed in the development of vaccine and adjuvant formulations tailored for older adults in order to boost protective immunity and overcome immunosenescence. In this review, we will discuss the development of vaccines for older adults in light of our current understanding-or lack thereof-of the aging immune system. We highlight the functional changes that are known to occur in the adaptive immune system with age, followed by a discussion of current, clinically relevant pathogens that disproportionately affect older adults and are the central focus of vaccine research efforts for the aging population. We conclude with an outlook on personalized vaccine development for older adults and areas in need of further study in order to improve our fundamental understanding of adaptive immunosenescence.