Twelve years of pneumococcal conjugate vaccination in the Netherlands: Impact on incidence and clinical outcomes of invasive pneumococcal disease

Effects of PCV10 and PCV13 on pneumococcal serotype 6C disease, carriage, and antimicrobial resistance

BACKGROUND

The cross-protection of pneumococcal conjugate vaccines (PCV) against serotype 6C is not clearly documented, although 6C represents a substantial burden of pneumococcal disease in recent years. A systematic review by the World Health Organization that covered studies through 2016 concluded that available data were insufficient to determine if either PCV10 (which contains serotype 6B but not 6A) or PCV13 (containing serotype 6A and 6B) conferred protection against 6C.

METHODS

We performed a systematic review of randomized controlled trials and observational studies published between January 2010 - August 2022 (Medline/Embase), covering the direct, indirect, and overall effect of PCV10 and PCV13 against 6C invasive pneumococcal disease (IPD), non-IPD, nasopharyngeal carriage (NPC), and antimicrobial resistance (AMR).

RESULTS

Of 2548 publications identified, 112 were included. Direct vaccine effectiveness against 6C IPD in children ranged between 70 and 85 % for ≥ 1 dose PCV13 (n = 3 studies), was 94 % in fully PCV13 vaccinated children (n = 2), and -14 % for ≥ 1 dose of PCV10 (n = 1). Compared to PCV7, PCV13 efficacy against 6C NPC in children was 66 % (n = 1). Serotype 6C IPD rates or NPC prevalence declined post-PCV13 in most studies in children (n = 5/6) and almost half of studies in adults (n = 5/11), while it increased post-PCV10 for IPD and non-IPD in all studies (n = 6/6). Changes in AMR prevalence were inconsistent.

CONCLUSIONS

In contrast to PCV10, PCV13 vaccination consistently protected against 6C IPD and NPC in children, and provided some level of indirect protection to adults, supporting that serotype 6A but not 6B provides cross-protection to 6C. Vaccine policy makers and regulators should consider the effects of serotype 6A-containing PCVs against serotype 6C disease in their decisions.

Antimicrobial Resistance of Streptococcus pneumoniae Clinical Serotypes between 2017 and 2022 in Crete, Greece

BACKGROUND

Pneumococcal disease is still considered a global problem. With the introduction of pneumococcal conjugate vaccines (PCVs) serotype epidemiology changed, but antimicrobial resistance persists constituting a serious problem. The current study aimed to determine the serotype distribution and the antimicrobial susceptibility of recent Streptococcus pneumoniae isolates, following implementation of the 13-valent conjugate vaccine (PCV13).

MATERIALS AND METHODS

From January 2017 to December 2022 we evaluated 116 nonduplicate S. pneumoniae isolates collected from adult patients (21 - 98 years) cared for in the University Hospital of Heraklion, Crete, Greece. Pneumococcal isolates were serotyped by the Quellung reaction, and antimicrobial susceptibility testing was performed using E-test. Multidrug resistance (MDR) was defined as non-susceptibility to at least one agent in ≥3 classes of antibiotics.

RESULTS

Among the 116 isolates, 31% were recognized as invasive pneumococcal strains, while 69% were non-invasive. The isolates tested belonged to 25 different serotypes. The most prevalent serotypes were 11A (10.3%), and 35B (10.3%), followed by 3 (9.5%), 15A (7.8%), 25F (6.9%), 19A (5.3%), 35F (5.3%), and others (44.6%). The coverage rates of PCV13 and the pneumococcal polysaccharide vaccine (PPSV23) were 26.7% and 57.8%, respectively. PCV13 and PPSV23 serotypes decreased between 2017 - 2019 and 2020 - 2022, with a parallel increase in the non-vaccine types. Resistance rates to erythromycin, clindamycin, trimethoprim/sulfamethoxazole, penicillin, levofloxacin, and ceftriaxone, were 40.5%, 21.6%, 13.8%, 12.1%, 3.4%, and 0%, respectively. All isolates were susceptible to vancomycin, linezolid, and daptomycin. MDR was observed among 36 (31%) S. pneumoniae isolates.

CONCLUSION

The increasing levels of resistance in S. pneumoniae in Crete, Greece, highlight the need for continuous surveillance of antimicrobial resistance and development of strategies for its reduction, including antimicrobial stewardship programs, increased pneumococcal vaccination, and development of next generation PCVs with a wider serotype coverage.

Higher-valency pneumococcal conjugate vaccines in older adults, taking into account indirect effects from childhood vaccination: a cost-effectiveness study for the Netherlands

BACKGROUND

New 15- and 20-valent pneumococcal vaccines (PCV15, PCV20) are available for both children and adults, while PCV21 for adults is in development. However, their cost-effectiveness for older adults, taking into account indirect protection and serotype replacement from a switch to PCV15 and PCV20 in childhood vaccination, remains unexamined.

METHODS

We used a static model for the Netherlands to assess the cost-effectiveness of different strategies with 23-valent pneumococcal polysaccharide vaccine (PPV23), PCV15, PCV20, and PCV21 for a 65-year-old cohort from a societal perspective, over a 15-year time horizon. Childhood vaccination was varied from PCV10 to PCV13, PCV15, and PCV20. Indirect protection was assumed to reduce the incidence of vaccine serotypes in older adults by 80% (except for serotype 3, no effect), completely offset by an increase in non-vaccine serotype incidence due to serotype replacement.

RESULTS

Indirect effects from childhood vaccination reduced the cost-effectiveness of vaccination of older adults, depending on the serotype overlap between the vaccines. With PCV10, PCV13, or PCV15 in children, PCV20 was more effective and less costly for older adults than PPV23 and PCV15. PCV20 costs approximately €10,000 per quality-adjusted life year (QALY) gained compared to no pneumococcal vaccination, which falls below the conventional Dutch €20,000/QALY gained threshold. However, with PCV20 in children, PCV20 was no longer considered cost-effective for older adults, costing €22,550/QALY gained. As indirect effects progressed over time, the cost-effectiveness of PCV20 for older adults further diminished for newly vaccinated cohorts. PPV23 was more cost-effective than PCV20 for cohorts vaccinated 3 years after the switch to PCV20 in children. PCV21 offered the most QALY gains, and its cost-effectiveness was minimally affected by indirect effects due to its coverage of 11 different serotypes compared to PCV20.

CONCLUSIONS

For long-term cost-effectiveness in the Netherlands, the pneumococcal vaccine for older adults should either include invasive serotypes not covered by childhood vaccination or become more affordable than its current pricing for individual use.

Long-term surveillance of invasive pneumococcal disease: The impact of 10-valent pneumococcal conjugate vaccine in the metropolitan region of Salvador, Brazil

BACKGROUND

In 2010, Brazil introduced the ten-valent pneumococcal conjugate vaccine (PCV10) in the national infant immunization program. Limited data on the long-term impact of PCV10 are available from lower-middle-income settings. We examined invasive pneumococcal disease (IPD) in Salvador, Bahia, over 11 years.

METHODS

Prospective laboratory-based surveillance for IPD was carried out in 9 hospitals in the metropolitan region of Salvador from 2008 to 2018. IPD was defined as Streptococcus pneumoniae cultured from a normally sterile site. Serotype was determined by multiplex polymerase chain reaction and/or Quellung reaction. Incidence rates per 100,000 inhabitants were calculated for overall, vaccine-type, and non-vaccine-type IPD using census data as the denominator. Incidence rate ratios (IRRs) were calculated to compare rates during the early (2010-2012), intermediate (2013-2015), and late (2016-2018) post-PCV10 periods in comparison to the pre-PCV10 period (2008-2009).

RESULTS

Pre-PCV10, overall IPD incidence among all ages was 2.48/100,000. After PCV10 introduction, incidence initially increased (early post-PCV10 IRR 3.80, 95% CI 1.18-1.99) and then declined to 0.38/100,000 late post-PCV10 (IRR 0.15; 95% CI 0.09-0.26). The greatest reductions in the late post-PCV10 period were observed in children aged ≤2 years, with no cases (IRR not calculated) and those ≥60 years (IRR 0.11, 95% CI 0.03-0.48). Late post-PCV10, significant reductions were observed for both PCV10 serotypes (IRR 0.02; 95% CI 0.0-0.15) and non-PCV10 serotypes (IRR 0.27; 95%CI 0.14-0.53). Non-PCV10 serotypes 15B, 12F, 3, 17F, and 19A became predominant late post-PCV10 without a significant increase in serotype-specific IPD incidence compared to pre-PCV10.

CONCLUSION

Significant declines in IPD, including among adults not eligible for vaccination, suggest direct and indirect protection up to nine years after PCV10 introduction, without evidence of significant replacement disease. Continued surveillance is needed to monitor changes in non-vaccine serotypes and inform decisions about introducing higher valent PCVs.

Assessing Public Health Impact of Four Pediatric Pneumococcal Conjugate Vaccination Strategies in the Netherlands

INTRODUCTION

The 10-valent pneumococcal conjugate vaccine (PCV10, Synflorix) was introduced into the Dutch pediatric national immunization program (NIP) starting in 2011. However, there is substantial pneumococcal disease burden due to increases in non-PCV10 covered serotypes. Higher-valent vaccines for pediatrics (PCV13, PCV15, and PCV20) may alleviate much of the remaining disease burden upon implementation through broader serotype coverage. This article assesses the public health impact of different pediatric vaccination strategies (switching to PCV13, PCV15 or PCV20) versus maintaining PCV10 at different time intervals in the Netherlands.

METHODS

A population-based, decision-analytic model was developed using historical pneumococcal disease surveillance data to forecast future invasive pneumococcal disease (IPD), pneumonia, and otitis media (OM) cases over a 7-year period (2023-2029) under the following strategies: continued use of PCV10, switching to PCV13 in 2023, switching to PCV15 in 2023, and switching to PCV20 in 2024. Scenario analyses were performed to account for uncertainties in future serotype distributions, disease incidence reductions, and epidemiologic parameters.

RESULTS

Switching to PCV13 in 2023 was found to avert 26,666 cases of pneumococcal disease compared to continuing PCV10 over a 7-year period (2023-2029). Switching to PCV15 in 2023 was found to avert 30,645 pneumococcal cases over the same period. Switching to PCV20 once available in 2024 was estimated to avert 45,127 pneumococcal cases from 2024-2029. Overall conclusions were maintained after testing uncertainties.

CONCLUSIONS

For the Dutch pediatric NIP, switching to PCV13 in 2023 would be an effective strategy compared with continued use of PCV10 for averting pneumococcal disease cases. Switching to PCV20 in 2024 was estimated to avert the most pneumococcal disease cases and provide the highest protection. However, in the face of budget constraints and the undervaluation of prevention strategies, it remains challenging to implement higher valent vaccines. Further research is needed to understand the cost-effectiveness and feasibility of a sequential approach.

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

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

The burden of invasive meningococcal disease in the Netherlands, 2011-2020

INTRODUCTION

Representative information on disease course and outcome of invasive meningococcal disease (IMD) is important because of the shift in meningococcal epidemiology that recently occurred in the Netherlands. With this study, we update earlier research on the burden of IMD in the Netherlands.

MATERIAL AND METHODS

We performed a retrospective study using Dutch surveillance data on IMD from July 2011 to May 2020. Clinical information was collected from hospital records. The effect of age, serogroup, and clinical manifestation on disease course and outcome was assessed in multivariable logistic regression analyses. Grouping of infecting isolates was performed by Ouchterlony gel diffusion or by PCR.

RESULTS

Clinical information was collected for 278 IMD cases of which the majority had IMD-B (55%), followed by IMD-W (27%), IMD-Y (13%), and IMD-C (5%). Most patients presented with meningitis (32%) or sepsis (30%). Hospitalisation for ≥ 10 days was most frequent among 24-64 year olds (67%). ICU admission was highest among 24-64 year olds (60%), and in case of sepsis (70%), or sepsis plus meningitis (61%). Sequelae at discharge was lower for patients with mild meningococcaemia compared to patients with sepsis plus meningitis (OR: 0.19, 95% CI: 0.07-0.51). The overall case fatality rate was 7%, and was highest for IMD-Y (14%) and IMD-W (13%) patients.

CONCLUSIONS

IMD remains a disease with high morbidity and mortality. Sepsis (with or without meningitis) is associated with a more severe disease course and outcome compared to other clinical manifestations. The high disease burden can be partly prevented by meningococcal vaccination.

Systematic review on the impact of the pneumococcal conjugate vaccine ten valent (PCV10) or thirteen valent (PCV13) on all-cause, radiologically confirmed and severe pneumonia hospitalisation rates and pneumonia mortality in children 0-9 years old

Background

There is an ongoing need to assess the impact of pneumococcal conjugate vaccines (PCVs) to guide the use of these potentially valuable but under-utilized vaccines against pneumonia, which is one of the most common causes of post-neonatal mortality.

Methods

We conducted a systematic review of the literature on PCV10 and PCV13 impact on all-cause, radiologically confirmed and severe pneumonia hospitalisation rates as well as all-cause and pneumonia-specific mortality rates. We included studies that were published from 2003 onwards, had a post-licensure observational study design, and reported on any of our defined outcomes in children aged between 0-9 years. We derived incidence rates (IRs), incidence rate ratios (IRRs) or percent differences (%). We assessed all studies for risk of bias using the Effective Public Health Practice Project (EPHPP) quality assessment tool.

Results

We identified a total of 1885 studies and included 43 comparing one or more of the following hospitalised outcomes of interest: all-cause pneumonia (n = 27), severe pneumonia (n = 6), all-cause empyema (n = 8), radiologically confirmed pneumonia (n = 8), pneumococcal pneumonia (n = 7), and pneumonia mortality (n = 10). No studies evaluated all-cause mortality. Studies were conducted in all WHO regions except South East Asia Region (SEAR) and low- or middle-income countries (LMICs) in the Western Pacific Region (WPR). Among children <5 years old, PCV impact ranged from 7% to 60% for all-cause pneumonia hospitalisation, 8% to 90% for severe pneumonia hospitalisation, 12% to 79% for radiologically confirmed pneumonia, and 45% to 85% for pneumococcal confirmed pneumonia. For pneumonia-related mortality, impact was found in three studies and ranged from 10% to 78%. No obvious differences were found in vaccine impact between PCV10 and PCV13. One study found a 17% reduction in all-cause pneumonia among children aged 5-9 years, while another found a reduction of 81% among those aged 5-17 years. A third study found a 57% reduction in all-cause empyema among children 5-14 years of age.

Conclusion

We found clear evidence of declines in hospitalisation rates due to all-cause, severe, radiologically confirmed, and bacteraemic pneumococcal pneumonia in children aged <5 years, supporting ongoing use of PCV10 and PCV13. However, there were few studies from countries with the highest <5-year mortality and no studies from SEAR and LMICs in the WPR. Standardising methods of future PCV impact studies is recommended.

Validation of Fourier Transform Infrared Spectroscopy for Serotyping of Streptococcus pneumoniae

Fourier transform infrared (FT-IR) spectroscopy (IR Biotyper; Bruker) allows highly discriminatory fingerprinting of closely related bacterial strains. In this study, FT-IR spectroscopy-based capsular typing of Streptococcus pneumoniae was validated as a rapid, cost-effective, and medium-throughput alternative to the classical phenotypic techniques. A training set of 233 strains was defined, comprising 34 different serotypes and including all 24 vaccine types (VTs) and 10 non-vaccine types (NVTs). The acquired spectra were used to (i) create a dendrogram where strains clustered together according to their serotypes and (ii) train an artificial neural network (ANN) model to predict unknown pneumococcal serotypes. During validation using 153 additional strains, we reached 98.0% accuracy for determining serotypes represented in the training set. Next, the performance of the IR Biotyper was assessed using 124 strains representing 59 non-training set serotypes. In this setting, 42 of 59 serotypes (71.1%) could be accurately categorized as being non-training set serotypes. Furthermore, it was observed that comparability of spectra was affected by the source of the Columbia medium used to grow the pneumococci and that this complicated the robustness and standardization potential of FT-IR spectroscopy. A rigorous laboratory workflow in combination with specific ANN models that account for environmental noise parameters can be applied to overcome this issue in the near future. The IR Biotyper has the potential to be used as a fast, cost-effective, and accurate phenotypic serotyping tool for S. pneumoniae.

Pathogen- and Type-Specific Changes in Invasive Bacterial Disease Epidemiology during the First Year of the COVID-19 Pandemic in The Netherlands

COVID-19 control measures have resulted in a decline in invasive bacterial disease caused by Neisseria meningitidis (IMD), Streptococcus pneumoniae (IPD), and Haemophilus influenzae (Hi-D). These species comprise different serogroups and serotypes that impact transmissibility and virulence. We evaluated type- and pathogen-specific changes in invasive bacterial disease epidemiology in the Netherlands during the first year of the SARS-CoV-2 pandemic. Cases were based on nationwide surveillance for five bacterial species with either respiratory (IMD, IPD, Hi-D) or non-respiratory (controls) transmission routes and were compared from the pre-COVID period (April 2015−March 2020) to the first COVID-19 year (April 2020−March 2021). IMD, IPD, and Hi-D cases decreased by 78%, 67%, and 35%, respectively, in the first COVID-19 year compared to the pre-COVID period, although effects differed per age group. Serogroup B-IMD declined by 61%, while serogroup W and Y-IMD decreased >90%. IPD caused by serotypes 7F, 15A, 12F, 33F, and 8 showed the most pronounced decline (≥76%). In contrast to an overall decrease in Hi-D cases, vaccine-preventable serotype b (Hib) increased by 51%. COVID-19 control measures had pathogen- and type-specific effects related to invasive infections. Continued surveillance is critical to monitor potential rebound effects once restriction measures are lifted and transmission is resumed.

Pneumonia and Invasive Pneumococcal Diseases: The Role of Pneumococcal Conjugate Vaccine in the Era of Multi-Drug Resistance

Streptococcus pneumoniae related diseases are a leading cause of morbidity and mortality, especially in children and in the elderly population. It is transmitted to other individuals through droplets and it can spread to other parts of the human host, causing a wide spectrum of clinical syndromes, affecting between 10 and 100 cases per 100,000 people in Europe and the USA. In order to reduce morbidity and mortality caused by this agent, pneumococcal vaccines have been developed over the years and have shown incredible effectiveness in reducing the spread of this bacterium and the development of related diseases, obtaining a significant reduction in mortality, especially in developing countries. However, considerable problems are emerging mainly due to the replacement phenomenon, multi-drug resistance, and the high production costs of conjugated vaccines. There is still a debate about the indications given by various countries to different age groups; this is one of the reasons for the diffusion of different serotypes. To cope with these problems, significant efforts have been made in the research field to further improve vaccination serotypes coverage. On the other hand, an equally important commitment by health care systems to all age group populations is needed to improve vaccination coverage.

Invasive pneumococcal disease among adults with hematological and solid organ malignancies: A population-based cohort study

OBJECTIVES

To determine the risk of invasive pneumococcal disease (IPD) in adult cancer patients stratified by type of underlying malignancy, age, and capsular serotype and to assess herd effects of childhood pneumococcal vaccination.

METHODS

All adult IPD cases reported to the Dutch pneumococcal surveillance system between 2004 and 2016 were included in this study. IPD incidence rates (IR) stratified by subtype of malignancy were calculated per 100 000 patient-years of follow-up. Incidence rate ratios (IRR) were calculated to compare IRs between groups.

RESULTS

A total of 7167 IPD cases were included, of which 1453 were in patients with malignancies. For patients with hematological malignancies (HM) and solid organ malignancies (SOM), IRs were 482/100 000 and 79/100 000, respectively, compared with 15/100 000 in controls. The highest incidence was observed among patients with multiple myeloma, non-Hodgkin lymphoma, chronic lymphocytic leukemia, pancreatic cancer, and lung cancer (3299/100 000, 2717/100 000, 538/100 000, 559/100 000, and 393/100 000, respectively), and in patients ≥50 years old. Among HM patients, the incidence of IPD declined significantly after the implementation of infant pneumococcal vaccination (IRR 0.65, 95% confidence interval 0.51-0.84); among SOM patients, the decline was not statistically significant (IRR 0.88, 95% confidence interval 0.72-1.07).

CONCLUSIONS

The IPD disease burden in cancer patients remains high. Large differences in IPD incidence between the different types of cancer demand tailored guidance regarding pneumococcal vaccination.

Dynamics of antimicrobial resistance of Streptococcus pneumoniae following PCV10 introduction in Brazil: Nationwide surveillance from 2007 to 2019

BACKGROUND

Brazil introduced 10-valent pneumococcal conjugate vaccine (PCV10) into its immunization program in 2010. We assessed antimicrobial susceptibility of Streptococcus pneumoniae (Spn) obtained from a national surveillance system for invasive pneumococcal diseases (IPD) before/after PCV10 introduction.

METHODS

Antimicrobial non-susceptible isolates were defined as intermediate or resistant. Minimum inhibitory concentrations (MICs) to penicillin and ceftriaxone were analyzed by year. Antimicrobial susceptibility rates were assessed for each three-year-period using the pre-PCV10-period as reference. Susceptibility of vaccine-types was evaluated for 2017-2019.

RESULTS

11,380 isolates were studied. Spn with penicillin ≥ 0.125 mg/L and ceftriaxone ≥ 1.0 mg/L decreased in the three-years after PCV10 introduction (2011-2013: penicillin, 28.1-22.5%; ceftriaxone, 11.3%-7.6%) versus pre-PCV10-years (2007-2009: penicillin, 33.8-38.1%; ceftriaxone, 17.2%-15.6%). After 2013, the proportion of Spn with those MICs to penicillin and ceftriaxone increased to 39.4% and 19.7% in 2019, respectively. Non-susceptibility to penicillin and ceftriaxone increased in 2014-2016, and again in 2017-2019 especially among children < 5 years with meningitis (penicillin, 53.9%; ceftriaxone, 28.0%); multidrug-resistance reached 25% in 2017-2019. Serotypes 19A, 6C and 23A were most associated with antimicrobial non-susceptibility.

CONCLUSIONS

Antimicrobial non-susceptible Spn decreased in the three-years after vaccination but subsequently increased and was associated with non-PCV10-types. Antimicrobial susceptibility surveillance is fundamental for guiding antibiotic therapy policies.

Vaccines for older adults

The proportion of the global population aged 65 and older is rapidly increasing. Infections in this age group, most recently with SARS-CoV-2, cause substantial morbidity and mortality. Major improvements have been made in vaccines for older people, either through the addition of novel adjuvants-as in the new recombinant zoster vaccine and an adjuvanted influenza vaccine-or by increasing antigen concentration, as in influenza vaccines. In this article we review improvements in immunization for the three most important vaccine preventable diseases of aging. The recombinant zoster vaccine has an efficacy of 90% that is minimally affected by the age of the person being vaccinated and persists for more than four years. Increasing antigen dose or inclusion of adjuvant has improved the immunogenicity of influenza vaccines in older adults, although the relative effectiveness of the enhanced influenza vaccines and the durability of the immune response are the focus of ongoing clinical trials. Conjugate and polysaccharide pneumococcal vaccines have similar efficacy against invasive pneumococcal disease and pneumococcal pneumonia caused by vaccine serotypes in older adults. Their relative value varies by setting, depending on the prevalence of vaccine serotypes, largely related to conjugate vaccine coverage in children. Improved efficacy will increase public confidence and uptake of these vaccines. Co-administration of these vaccines is feasible and important for maximal uptake in older people. Development of new vaccine platforms has accelerated following the arrival of SARS-CoV-2, and will likely result in new vaccines against other pathogens in the future.

Pneumococcal Pneumonia and Invasive Pneumococcal Disease in Those 65 and Older: Rates of Detection, Risk Factors, Vaccine Effectiveness, Hospitalisation and Mortality

Pneumococcal pneumonia (PP) and invasive pneumococcal disease (IPD) are important causes of morbidity and mortality in seniors worldwide. Incidence rates and serious outcomes worsen with increasing frailty, numbers of risk factors and decreasing immune competence with increasing age. Literature reviews in Medline and Embase were performed for pneumococcal disease incidence, risk factors, vaccination rates and effectiveness in the elderly. The introduction of protein-conjugated pneumoccal vaccines (PCV) for children markedly reduced IPD and PP in seniors, but serotypes not included in vaccines and with previously low levels increased. Pneumococcal polysaccharide (PPV23) vaccination does not change nasal and pharyngeal carriage rates. Pneumococcal and influenza vaccination rates in seniors are below guideline levels, especially in older seniors and nursing home staff. Pneumococcal and influenza carriage and vaccination rates of family members, nursing home health care workers and other contacts are unknown. National vaccination programmes are effective in increasing vaccination rates. Detection of IPD and PP initially depend on clinical symptoms and new chest X ray infiltrates and then varies according to the population and laboratory tests used. To understand how seniors and especially older seniors acquire PP and IPD data are needed on pneumococcal disease and carriage rates in family members, carers and contacts. Nursing homes need reconfiguring into small units with air ventilation externally from all rooms to minimise respiratory disease transmission and dedicated staff for each unit to minimise transmision of infectious diseaases.

Impact and effectiveness of the 10-valent pneumococcal conjugate vaccine on invasive pneumococcal disease among children under 5 years of age in the Netherlands

BACKGROUND

In 2011, the 7-valent pneumococcal conjugate vaccine (PCV7) was replaced by the 10-valent vaccine (PCV10) in the Netherlands. We report on impact and effectiveness against invasive pneumococcal disease (IPD) in children aged under 5 years by switching from PCV7 to PCV10.

METHOD

We included IPD cases between 2004 and 2019 in children aged < 5 years reported via the national surveillance system. To assess the impact of the PCV10 vaccination program we compared IPD incidence 6-8 years after PCV10 introduction (2017-2019) to the two years just before the switch to PCV10 (2009-2011). We estimated vaccine effectiveness (VE) using the indirect cohort method, comparing vaccination status (at least two vaccine doses) in IPD-cases caused by PCV10 serotypes (cases) to non-PCV10 IPD cases (controls), in children eligible for PCV10.

RESULTS

The overall incidence decreased from 8.7 (n = 162) in 2009-2011 to 7.3 per 100.000 (n = 127) in 2017-2019 (Incidence rate ratio (IRR) 0.83, 95%CI: 0.66; 1.05). IPD caused by the additional serotypes included in PCV10 declined by 93% (IRR 0.07, 95%CI: 0.02; 0.23). Incidence of non-PCV10 IPD showed a non-significant increase (IRR 1.25, 95%CI: 0.96; 1.63). Among 231 IPD-cases eligible for PCV10, the overall VE was 91% (95%CI: 67; 97) and did not differ by sex or age at diagnosis. Effectiveness against non-PCV10 serotype 19A IPD was non-significant with an estimate of 28% (95%CI:-179; 81).

CONCLUSION

PCV10 is highly effective in protecting against IPD in Dutch children under 5 years with limited serotype replacement after switching from PCV7 to PCV10. We found no evidence for significant cross-protection of PCV10 against 19A serotype IPD.

Age and Location in Severity of COVID-19 Pathology: Do Lactoferrin and Pneumococcal Vaccination Explain Low Infant Mortality and Regional Differences?

Two conundrums puzzle COVID-19 investigators: 1) morbidity and mortality is rare among infants and young children and 2) rates of morbidity and mortality exhibit large variances across nations, locales, and even within cities. It is found that the higher the rate of pneumococcal vaccination in a nation (or city) the lower the COVID-19 morbidity and mortality. Vaccination rates with Bacillus Calmette-Guerin, poliovirus, and other vaccines do not correlate with COVID-19 risks, nor do COVID-19 case or death rates correlate with number of people in the population with diabetes, obesity, or adults over 65. Infant protection may be due to maternal antibodies and antiviral proteins in milk such as lactoferrin that are known to protect against coronavirus infections. Subsequent protection might then be conferred (and correlate with) rates of Haemophilus influenzae type B (Hib) (universal in infants) and pneumococcal vaccination, the latter varying widely by geography among infants, at-risk adults, and the elderly. Also see the video abstract here https://youtu.be/GODBYRbPL00.

Pediatric parapneumonic effusion before and after national pneumococcal vaccination programs in Taiwan

BACKGROUND

Reports on the effectiveness of pneumococcal conjugate vaccines (PCVs) on pediatric parapneumonic effusion are limited. We report the changes in cases and etiologies of pediatric parapneumonic effusion in a children's hospital before and after national PCV13 vaccination programs.

METHODS

We screened medical records of children 0-18 years admitted to the National Taiwan University Hospital with diagnoses of lobar pneumonia and parapneumonic effusion between 2008 and 2017. Patients with effusion analyses were included. Results of blood, pleural fluid, and respiratory specimens surveyed as standard care were analyzed.

RESULTS

Diagnostic testing revealed at least a pathogen in 85% of 202 children with lobar pneumonia and parapneumonic effusion. After national PCV13 immunization, pneumococcal empyema decreased by 72% among 2- to 5-year olds. Mycoplasma pneumoniae was the second most common etiology. There were marked differences in effusion characteristics, metabolic, and respiratory parameters between children infected with pneumococcus and M. pneumoniae.

CONCLUSION

The effectiveness of the national PCV13 immunization programs on pneumococcal empyema was evident and remained substantial after 4 years in Taiwan. Continuous surveillance is important to monitor the emergence of other pathogens including non-PCV serotypes and M. pneumoniae.