Pneumococcal conjugate vaccine use for the prevention of pneumococcal disease in adults <50 years of age

Establishment of Safety Monitoring System for Vaccines Not Included in the National Immunization Program in Korea

BACKGROUND

In Korea, there are no surveillance programs for vaccines that are not included in the national immunization program (NIP), and vaccine safety monitoring in the adult population is inadequate. This study aimed to establish a safety monitoring system for non-NIP vaccines in adults.

METHODS

Frequently administered non-NIP vaccines were selected. Individuals were included if they received at least one of the selected vaccines at a participating institution and provided informed consent. Solicited and unsolicited adverse events were monitored using questionnaires sent through text messages on days 1, 3, 7, 28, and 90 post-vaccination. Selected adverse events of special interest (AESIs) were monitored monthly by retrospective review of electronic medical records. Causality was assessed according to the Korea Disease Control and Prevention Agency guidelines.

RESULTS

Four vaccines (tetanus-diphtheria-pertussis [Tdap], pneumococcal conjugate 13-valent [PCV13], live zoster vaccine [ZVL], and recombinant zoster vaccine [RZV]) were selected, and their safety profiles were monitored at four tertiary hospitals and 10 primary care clinics. The response rates of the questionnaires on post-vaccination days 1, 7, 28, and 90 were 99.2%, 93.6%, 81.0%, and 48.7%, respectively. Of 555 AESI identified over 10 months, 10 cases received one of the selected non-NIP vaccines within 90 days of the event.

CONCLUSION

We are establishing the first safety monitoring system for selected non-NIP vaccines in Korea since September 2022 and report its progress as of July 2023. However, continuous government support is essential for its maintenance and improvement.

Effect of Pneumococcal Vaccine on Mortality and Cardiovascular Outcomes: A Systematic Review and Meta-Analysis

Various studies have suggested the possible cardiovascular (CV) protective effects of the pneumococcal vaccine (PV). Therefore, we conducted a meta-analysis to assess the association between recipients of PV with mortality and CV outcomes among patients with and without established cardiovascular disease. We performed a systematic literature search in PubMed, Embase, and Scopus for studies evaluating the effect of PV on mortality and CV outcomes. A total of 15 studies with 347,444 patients were included in the meta-analysis: 111,784 patients received PV (32%) and 235,660 patients were in the unvaccinated group (68%). Recipients of PV were associated with decreased all-cause mortality (HR, 0.76 (95% CI: 0.66 to 0.87), p < 0.001). PV was associated with a decrease in the incidence of myocardial infarction (MI) (HR, 0.73 (95% CI: 0.56−0.96), p = 0.02), without significant reduction in CV mortality (HR, 0.87 (95% CI: 0.72−1.07), p = 0.18) and stroke (HR, 1.01 (95% CI: 0.93−1.10), p = 0.82). Our study found PV was associated with decreased risk of all-cause mortality and MI. Future RCTs will be necessary to confirm benefits associated with receipt of PV.

Vaccine-driven lung TRM cells provide immunity against Klebsiella via fibroblast IL-17R signaling

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Promoting Healthy Ageing in South Africa Through Vaccination of the Elderly

The World Health Organization estimates that globally, the proportion of people aged ≥60 years will more than double by the year 2050, with the majority of elderly people living in low- and middle-income countries such as South Africa. Population ageing is an impending public health concern, potentially negatively impacting on South Africa's economy and health system if the government does not adequately prepare for this change. Globally, many potential solutions to ensure healthy ageing are being discussed and implemented, including adopting a “life-course” approach to vaccination which includes vaccination of the elderly, since they are at considerable risk of severe morbidity and mortality from vaccine-preventable diseases. While vaccines are considered as one of the greatest tools for preventing childhood infectious disease morbidity and mortality, they are under-utilised in strategies for promoting healthy ageing in South Africa, where only influenza vaccination is available free of charge to the elderly accessing public sector healthcare. Population ageing coupled with the high incidence of vaccine-preventable diseases amongst elderly South Africans, necessitates establishing a comprehensive national policy and guidelines for vaccination of the elderly.

The Emergence of Invasive Streptococcus pneumoniae Serotype 24F in Lebanon: Complete Genome Sequencing Reveals High Virulence and Antimicrobial Resistance Characteristics

Background

Invasive pneumococcal disease (IPD) remains a global health problem. IPD incidence has significantly decreased by the use of pneumococcal conjugate vaccines (PCV). Nevertheless, non-PCV serotypes remain a matter of concern. Eight Streptococcus pneumoniae serotype 24F isolates, belonging to a non-PCV serotype, were detected through the Lebanese Inter-Hospital Pneumococcal Surveillance Program. The aim of the study is to characterize phenotypic and genomic features of the 24F isolates in Lebanon.

Methods

WGS using long reads sequencing (PacBio) was performed to produce complete circular genomes and to determine clonality, antimicrobial resistance and virulence determinants.

Results

The sequencing results yielded eight closed circular genomes. Three multilocus sequence typing (MLST) types were identified (ST11618, ST14184, ST15253). Both MLST and WGS analyses revealed that these isolates from Lebanon were genetically homogenous belonging to clonal complex CC230 and clustered closely with isolates originating from Canada, United States of America, United Kingdom and Iceland. Their penicillin binding protein profiles correlated with both β-lactam susceptibility patterns and MLST types. Moreover, the isolates harbored the macrolide and tetracycline resistance genes and showed a similar virulence gene profile. To our knowledge, this study represents the first report of complete phenotypic and genomic characterization of the emerging Streptococcus pneumoniae, serotype 24F, in the Middle East and North Africa region.

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.

Rates of hospitalization for community-acquired pneumonia among US adults: A systematic review

BACKGROUND

Community-acquired pneumonia (CAP) is associated with significant disease burden in adults but has not been measured uniformly. Reconciling differences across studies is critical for understanding the true burden of CAP.

METHODS

We performed a systematic literature review of the incidence of hospitalized CAP among US adults and described the impact of key study characteristics on these estimates.

RESULTS

After review of 8361 articles as of January 31, 2019, we identified 28 studies with 41 unique estimates of hospitalized CAP incidence. Among adults ≥65 years of age, annual rates of hospitalized CAP ranged from 847 to 3500 per 100,000 persons with median = 1830. Rates were lower in studies that excluded patients with healthcare-associated (but community-onset) pneumonia (HCAP; median = 2003 vs 1286; P = 0.02) or immunocompromising conditions (median = 1895 vs 1409; P = 0.27) compared to those that did not. Rates of CAP were also lower in studies that used more restrictive criteria for diagnosing pneumonia (eg, pneumonia coded in any diagnosis position [median = 2270] vs pneumonia coded in the first position only [median = 1375] in studies of administrative claims; P = 0.02). For adults <65 years of age, rates of CAP were lower (range: 89 to 1138 per 100,000; median = 199).

CONCLUSIONS

CAP causes a significant disease burden among adults, particularly among those ≥65 years of age. Commonly-applied exclusion criteria (eg, persons with HCAP or immunocompromising conditions) or restrictive case definitions (eg, only including pneumonias coded in the primary diagnosis position) have led to systematic underestimation of CAP incidence in many previous studies. In studies that did not apply these restrictive criteria, the rate of hospitalization was approximately 2000 per 100,000 annually. Understanding the true burden of adult CAP is critical for highlighting the ongoing need for expanded prevention programs, including vaccination.

Mortality and costs of pneumococcal pneumonia in adults: a cross-sectional study

Objective

Pneumococcal pneumonia is a significant cause of morbidity and mortality among adults. The study’s main aim was to evaluate the in-hospital mortality and related costs of community-acquired pneumococcal pneumonia in adults.

Methods

This cross-sectional study used medical records of adult patients with pneumococcal pneumonia hospitalized in a university hospital in Brazil from October 2009 to April 2017. All patients aged ≥ 18 years diagnosed with pneumococcal pneumonia were included. Risk factors, intensive care unit admission, length of hospital stay, in-hospital mortality, and direct and indirect costs were analyzed.

Results

In total, 186 patients were selected. The mean in-hospital mortality rate was 18% for adults aged < 65 years and 23% for the elderly (≥ 65 years). Bacteremic pneumococcal pneumonia affected 20% of patients in both groups, mainly through chronic respiratory disease (adjusted OR: 3.07, 95% CI: 1.23–7.65, p < 0.01). Over 7 years, annual total direct and indirect costs were USD 28,188 for adults < 65 years (USD 1,746 per capita) and USD 16,350 for the elderly (USD 2,119 per capita).

Conclusion

Pneumococcal pneumonia remains an important cause of morbidity and mortality among adults, significantly affecting direct and indirect costs. These results suggest the need for prevention strategies for all adults, especially for patients with chronic respiratory diseases.

Changes in serotype distribution and antimicrobial resistance of Streptococcus pneumoniae isolates from adult patients in Asia: Emergence of drug-resistant non-vaccine serotypes

This study was performed to investigate the serotype distribution and antimicrobial susceptibility of Streptococcus pneumoniae in Asian countries. A prospective surveillance study on S. pneumoniae collected from adult patients (≥50 years old) with invasive pneumococcal disease or community-acquired pneumonia was performed at 66 hospitals in Asian countries (Korea, China, Malaysia, Singapore, the Philippines, and Thailand) in 2012-2017. Serotyping and antimicrobial susceptibility tests of 850 pneumococcal isolates were performed. The proportions of isolates with serotypes covered by 13-valent pneumococcal conjugate vaccine (PCV13) were 37.0% in Korea, 53.4% in China, 77.2% in Malaysia, 35.9% in the Philippines, 68.7% in Singapore, and 60.2% in Thailand. Major serotypes were 19F (10.4%), 19A (10.1%), and 3 (8.5%) in 2012-2017, with different serotype distributions in each country. Macrolide resistance in pneumococci was high (66.8%) and prevalence of multidrug resistance (MDR) also remained high (50.8%). MDR non-PCV13 serotypes such as 11A, 15A, 35B, and 23A have emerged in Asian countries. This study showed the persistent prevalence of 19F and 19A with a noteworthy increase of certain non-PCV13 serotypes in Asian countries. High prevalence of macrolide resistance and MDR was also found in pneumococcal isolates. These data emphasize the need for continued surveillance of pneumococcal epidemiology in Asia in the post-pneumococcal vaccine era.

Cost-effectiveness of the 13-valent pneumococcal conjugate vaccine in adults in Portugal versus "no vaccination" and versus vaccination with the 23-valent pneumococcal polysaccharide vaccine

The burden of pneumococcal disease in adults is substantial from a social and economic point of view. This study assessed the cost-effectiveness of the 13-valent pneumococcal conjugate vaccine (PCV13) for the prevention of invasive pneumococcal disease and pneumococcal pneumonia in adults versus "no vaccination" and versus vaccination with the 23-valent pneumococcal polysaccharide vaccine (PPSV23). A Markov model was used to simulate three strategies: no vaccination, complete vaccination with PPSV23 and complete vaccination with PCV13. The comparison between strategies allowed the estimation of clinical and economic outcomes including incremental cost-effectiveness ratios (ICER) and incremental cost-utility ratios (ICUR). The model took into account the distributions of age, risk profile, vaccination status, type of immunization and time since vaccination in the population. A societal perspective was adopted and a lifetime horizon was considered. Different sources of data and assumptions were used to calibrate PPSV23 and PCV13 effectiveness. Inpatient costs were based on the 2013 diagnosis-related group (DRG) database for National Health Service (NHS) hospitals and expert opinion; NHS official tariffs were the main source for unitary costs. PCV13 shows ICURs of €17,746/QALY and €13,146/QALY versus "no vaccination" and vaccination with PPSV23, respectively. Results proved to be robust in univariate sensitivity analyses, where all ratios were below a €20,000 threshold, with the exception of the scenario with PCV13 effectiveness halved. In a probabilistic sensitivity analysis, 94% of simulations showed cost-effectiveness ratios lower than €20,000/QALY, in both strategies. It was found that PCV13 is a cost-effective strategy to prevent pneumococcal disease in adults in Portugal.

Decision-making for PCV in adults

Thirteen-valent pneumococcal conjugate vaccine (PCV13) was licensed in adults to address the unmet medical need of vaccine-type community acquired pneumonia (CAP) and the limitations of previous plain-polysaccharide vaccines. Since then, some have questioned the utility of adult PCV13 use, arguing that: i) high PCV13 uptake in young children would provide indirect effects that, by themselves, would sufficiently protect unvaccinated adults and ii) no data describing the real-world effectiveness of PCV13 use in adults, especially with immunocompromising conditions, exist. Even in countries like the United States where PCV13 has been routinely recommended for all adults aged ≥ 65 years, the recommendation is contingent on a re-evaluation to determine if continued use is needed in the context of a mature PCV13 pediatric immunization program. Emerging evidence, however, suggests that i) a meaningful burden of PCV13-type pneumococcal pneumonia still persists in adults at increased risk for pneumococcal disease, despite indirect effects from long-standing pediatric PCV13 use, ii) adult PCV13 use is effective and has reduced pneumococcal CAP, even in the elderly and those with chronic medical or immunocompromising conditions – and disease could come back if PCV13 were removed, and iii) ethical and pragmatic vaccine policy considerations support continued adult PCV13 use in countries that have already introduced the vaccine (eg, disparities in adult PCV13 uptake, confusion stemming from removing a previously-recommended vaccine for a non-safety-related concern, and the reality that next-generation PCVs are only a few years away). Together, these findings suggest that continued PCV13 vaccination in adults is needed to control vaccine-type CAP.