Invasive pneumococcal disease in the Netherlands: Syndromes, outcome and potential vaccine benefits

Approach to vaccination in systemic lupus erythematosus on biological treatment

In recent years, treat-to-target strategy and early intervention strategies with immunosuppressive agents have attempted to improve the prognosis and outcome in patients with autoimmune inflammatory rheumatic diseases. However, infectious complications due to side effects of medication remain a major concern in routine practice. In this regard, vaccine immunity and vaccination programmes are of the utmost importance in patients with systemic lupus erythematosus (SLE) in terms of morbidity and mortality. Encouragingly, research investigations have increased exponentially, both in monitoring the vaccines efficacy, and in determining the immune response while patients are on immunosuppression., However, in this biological era in rheumatology, relatively little data have been published investigating these parameters in those receiving biological agents, therefore, no definitive consensus about a vaccination policy for patients with SLE is currently available. In this review, we aim to address what is established about vaccinating patients with SLE on biological agents and discuss potential problems.

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.

A spitting image: molecular diagnostics applied to saliva enhance detection of Streptococcus pneumoniae and pneumococcal serotype carriage

Background

Despite strong historical records on the accuracy of saliva testing, oral fluids are considered poorly suited for pneumococcal carriage detection. We evaluated an approach for carriage surveillance and vaccine studies that increases the sensitivity and specificity of pneumococcus and pneumococcal serotype detection in saliva samples.

Methods

Quantitative PCR (qPCR)-based methods were applied to detect pneumococcus and pneumococcal serotypes in 971 saliva samples collected from 653 toddlers and 318 adults. Results were compared with culture-based and qPCR-based detection in nasopharyngeal samples collected from children and in nasopharyngeal and oropharyngeal samples collected from adults. Optimal C _q cut-offs for positivity in qPCRs were determined via receiver operating characteristic curve analysis and accuracy of different approaches was assessed using a composite reference for pneumococcal and for serotype carriage based on isolation of live pneumococcus from the person or positivity of saliva samples determined with qPCR. To evaluate the inter-laboratory reproducibility of the method, 229 culture-enriched samples were tested independently in the second center.

Results

In total, 51.5% of saliva samples from children and 31.8% of saliva samples from adults were positive for pneumococcus. Detection of pneumococcus by qPCR in culture-enriched saliva exhibited enhanced sensitivity and higher agreement with a composite reference compared to diagnostic culture of nasopharyngeal samples in children (Cohen's κ: 0.69-0.79 vs. 0.61-0.73) and in adults (κ: 0.84-0.95 vs. 0.04-0.33) and culture of oropharyngeal samples in adults (κ: 0.84-0.95 vs. -0.12-0.19). Similarly, detection of serotypes with qPCR in culture-enriched saliva exhibited enhanced sensitivity and higher agreement with a composite reference compared to nasopharyngeal culture in children (κ: 0.73-0.82 vs. 0.61-0.73) and adults (κ: 0.90-0.96 vs. 0.00-0.30) and oropharyngeal culture in adults (κ: 0.90-0.96 vs. -0.13 to 0.30). However, results of qPCRs targeting serotype 4, 5, and 17F and serogroups 9, 12, and 35 were excluded due to assays' lack of specificity. We observed excellent quantitative agreement for qPCR-based detection of pneumococcus between laboratories. After exclusion of serotype/serogroup-specific assays with insufficient specificity, moderate agreement (κ 0.68, 95% CI 0.58-0.77) was observed.

Conclusion

Molecular testing of culture-enriched saliva samples improves the sensitivity of overall surveillance of pneumococcal carriage in children and adults, but limitations of qPCR-based approaches for pneumococcal serotypes carriage detection should be considered.

It Takes Two to Tango: Combining Conventional Culture With Molecular Diagnostics Enhances Accuracy of Streptococcus pneumoniae Detection and Pneumococcal Serogroup/Serotype Determination in Carriage

Background

The specificity of molecular methods for the detection of Streptococcus pneumoniae carriage is under debate. We propose a procedure for carriage surveillance and vaccine impact studies that increases the accuracy of molecular detection of live pneumococci in polymicrobial respiratory samples.

Methods

Culture and qPCR methods were applied to detect pneumococcus and pneumococcal serotypes in 1,549 nasopharyngeal samples collected in the Netherlands (n = 972) and England (n = 577) from 946 toddlers and 603 adults, and in paired oropharyngeal samples collected exclusively from 319 Dutch adults. Samples with no live pneumococci isolated at primary diagnostic culture yet generating signal specific for pneumococcus in qPCRs were re-examined with a second, qPCR-guided culture. Optimal C_q cut-offs for positivity in qPCRs were determined via receiver operating characteristic (ROC) curve analysis using isolation of live pneumococci from the primary and qPCR-guided cultures as reference.

Results

Detection of pneumococcus and pneumococcal serotypes with qPCRs in cultured (culture-enriched) nasopharyngeal samples exhibited near-perfect agreement with conventional culture (Cohen’s kappa: 0.95). Molecular methods displayed increased sensitivity of detection for multiple serotype carriage, and implementation of qPCR-guided culturing significantly increased the proportion of nasopharyngeal and oropharyngeal samples from which live pneumococcus was recovered (p < 0.0001). For paired nasopharyngeal and oropharyngeal samples from adults none of the methods applied to a single sample type exhibited good agreement with results for primary and qPCR-guided nasopharyngeal and oropharyngeal cultures combined (Cohens kappa; 0.13–0.55). However, molecular detection of pneumococcus displayed increased sensitivity with culture-enriched oropharyngeal samples when compared with either nasopharyngeal or oropharyngeal primary cultures (p < 0.05).

Conclusion

The accuracy of pneumococcal carriage surveillance can be greatly improved by complementing conventional culture with qPCR and vice versa, by using results of conventional and qPCR-guided cultures to interpret qPCR data. The specificity of molecular methods for the detection of live pneumococci can be enhanced by incorporating statistical procedures based on ROC curve analysis. The procedure we propose for future carriage surveillance and vaccine impact studies improves detection of pneumococcal carriage in adults in particular and enhances the specificity of serotype carriage detection.

Diminished Pneumococcal-Specific CD4+ T-Cell Response is Associated With Increased Regulatory T Cells at Older Age

Respiratory infection caused by Streptococcus pneumoniae is a leading cause of morbidity and mortality in older adults. Acquired CD4+ T cell mechanism are essential for the protection against colonization and subsequent development of infections by S. pneumoniae. In this study, we hypothesized that age-related changes within the CD4+ T-cell population compromise CD4+ T-cell specific responses to S. pneumoniae, thereby contributing to increased susceptibility at older age. To this end, we interrogated the CD4+ T-cell response against the immunogenic pneumococcal protein AliB, part of the unique oligopeptide ABC transporter system responsible for the uptake of nutrients for the bacterium and crucial for the development of pneumococcal meningitis, in healthy young and older adults. Specifically, proliferation of CD4+ T cells as well as concomitant cytokine profiles and phenotypic markers implied in immunosenescence were studied. Older adults showed decreased AliB-induced CD4+ T-cell proliferation that is associated with an increased frequency of regulatory T cells and lower levels of active CD25+CD127+CTLA-4−TIGIT-CD4+T cells. Additionally, levels of pro-inflammatory cytokines IFNy and IL-17F were decreased at older age. Our findings indicate that key features of a pneumococcal-specific CD4+ T-cell immune response are altered at older age, which may contribute to enhanced susceptibility for pneumococcal infections.

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 incremental burden of invasive pneumococcal disease associated with a decline in childhood vaccination using a dynamic transmission model in Japan: A secondary impact of COVID-19

The coronavirus disease 2019 (COVID-19) pandemic has disrupted childhood vaccinations, including pneumococcal conjugate vaccine (PCV). Evaluating the possible impact on the invasive pneumococcal disease (IPD) incidence associated with a decline in childhood pneumococcal vaccination is important to advocate the PCV programs. Using a deterministic, dynamic transmission model, the differential incidence and burden of IPD in children younger than 5 years in Japan were estimated between the rapid vaccination recovery (January 2021) and the delayed vaccination recovery (April 2022) scenarios for the next 10 years. In our model, the IPD incidence was reduced from 11.9/100,000 in 2019 to 6.3/100,000 in 2020, caused by a reduced transmission rate due to the COVID-19 mitigation measures. Assuming a recovery in the transmission rate in 2022 April, the incidence of IPD was estimated to increase with maximal incidence of 12.1 and 13.1/100,000 children under 5 years in the rapid and the delayed vaccination recovery scenarios. The difference in the total IPD incidence between these two scenarios was primarily driven by vaccine serotypes IPD incidence. The difference of incidence was not observed between the two scenarios after 2025. The persistent decline in childhood pneumococcal vaccination rates due to the impact of COVID-19 might lead to an increased IPD incidence and an incremental disease burden.

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

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

Serotype distribution and clinical characteristics associated with streptococcus pneumoniae among Chinese children and adults with invasive pneumococcal disease: a multicenter observational study

Few studies in China focused on serotypes of Streptococcus pneumoniae in patients with invasive pneumococcal disease (IPD). We aimed at investigating the serotype distribution for IPD-causing S. pneumoniae and vaccine coverage among Chinese children and adults. This was a multicenter, observational study to collect S. pneumoniae isolates from normal sterile sites and IPD-related clinical information among children and adults. Serotyping was performed by a Capsule-Quellung reaction test using type-specific antisera. The study collected a total of 300 eligible isolates (pediatric = 148, adult = 152) were serotyped in a central laboratory. The most prevalent serotypes were 19A (20.9%) and 23 F (20.3%) in the pediatric group; 3 (21.7%) and 19 F (11.8%) in the adult group. PCV10 had low-to-moderate serotype coverage rates for children (60.8%) and adults (34.2%). PCV13 and PPV23 had high coverage rates for children (89.9%, 93.2%) and adults (70.4%, 82.9%), respectively, Investigational PCVs including PCV15 and PCV20 had high estimated coverage rates in children (89.9%, 93.9%). The study identified 269 subjects with IPD reported as the primary diagnosis in the medical records. Sepsis (48/136, 35.3%) and pneumonia (48/133, 36.1%) had the highest occurrence in the pediatric and adult groups, respectively. Study findings showed that non-PCV7 S. pneumoniae 19A and 3 were the most prevalent serotypes in Chinese children and adults, respectively. High-valent vaccines had similar coverage rates and may have a greater potential in preventing IPD.

A model for the incremental burden of invasive Haemophilus influenzae type b due to a decline of childhood vaccination during the COVID-19 outbreak: A dynamic transmission model in Japan

BACKGROUND

The current coronavirus disease 2019 (COVID-19) outbreak has caused a persistent decline in childhood vaccination coverage, including Haemophilus influenzae type b (Hib) vaccine, in some countries. Our objective was to evaluate the impact of decreased Hib vaccination due to COVID-19 on invasive Hib disease burden in Japan.

METHODS

Using a deterministic dynamic transmission model (susceptible-carriage-infection-recovery model), the incidence rates of invasive Hib disease in under 5 year olds in rapid vaccination recovery and persistent vaccination declined scenarios were compared for the next 10 years after 2020. The national Hib vaccination rate after the impact of COVID-19 reduced to 87% and 73% in 2020 from approximately 97% each in 2013-2019 for primary and booster doses.

RESULTS

While the persistent decline scenarios revealed an increase in invasive Hib disease incidence to 0.50/100,000 children under 5 years old, the incidence of the rapid recovery scenario slightly increased with a consistent decline of incidence after 2021. The shorter the duration of the decline in vaccination rate was, the smaller the incremental disease burden observed in the model. Compared to the rapid recovery scenario, the permanent decline scenario showed a 296.87 cumulative incremental quality-adjusted life years (QALY) loss for the next 10 years.

CONCLUSIONS

The persistent decline of Hib vaccination rate due to COVID-19 causes an incremental disease burden irrespective of the possible decline of Hib transmission rate by COVID-19 mitigation measures. A rapid recovery of vaccination coverage rate can prevent this possible incremental disease burden.

Influenza-like Illness Exacerbates Pneumococcal Carriage in Older Adults

BACKGROUND

In older adults pneumococcal disease is strongly associated with respiratory viral infections, but the impact of viruses on Streptococcus pneumoniae carriage prevalence and load remains poorly understood. Here, we investigated the effects of influenza-like illness (ILI) on pneumococcal carriage in community-dwelling older adults.

METHODS

We investigated the presence of pneumococcal DNA in saliva samples collected in the 2014/2015 influenza season from 232 individuals aged ≥60 years at ILI-onset, followed by sampling 2-3 weeks and 7-9 weeks after the first sample. We also sampled 194 age-matched controls twice 2-3 weeks apart. Pneumococcal DNA was detected with quantitative-PCRs targeting piaB and lytA genes in raw and in culture-enriched saliva. Bacterial and pneumococcal abundances were determined in raw saliva with 16S and piaB quantification.

RESULTS

The prevalence of pneumococcus-positive samples was highest at onset of ILI (18% or 42/232) and lowest among controls (13% or 26/194, and 11% or 22/194, at the first and second sampling moment, respectively), though these differences were not significant. Pneumococcal carriage was associated with exposure to young children (OR:2.71, 95%CI 1.51-5.02, p<0.001), and among asymptomatic controls with presence of rhinovirus infection (OR:4.23; 95%CI 1.16-14.22, p<0.05). When compared with carriers among controls, pneumococcal absolute abundances were significantly higher at onset of ILI (p<0.01), and remained elevated beyond recovery from ILI (p<0.05). Finally, pneumococcal abundances were highest in carriage events newly-detected after ILI-onset (estimated geometric mean 1.21E -5, 95%CI 2.48E -7-2.41E -5, compared with pre-existing carriage).

CONCLUSIONS

ILI exacerbates pneumococcal colonization of the airways in older adults, and this effect persists beyond recovery from ILI.

The Impact of the 13-Valent Pneumococcal Conjugate Vaccine on Pneumococcal Carriage in the Community Acquired Pneumonia Immunization Trial in Adults (CAPiTA) Study

Background

The impact of pneumococcal conjugate vaccination on the prevalence of nasopharyngeal carriage with pneumococci and other bacteria in adults is unknown. The direct effects of the 13-valent pneumococcal conjugate vaccine (PCV13) in community dwelling older adults was investigated as part of the randomized controlled Community Acquired Pneumonia immunization Trial in Adults (CAPiTA).

Methods

We determined the carriage of Streptococcus pneumoniae, Staphylococcus aureus, Haemophilus influenzae, and Moraxella catarrhalis before and 6, 12, and 24 months after vaccination using polymerase chain reaction (PCR)-based methods and conventional cultures of nasopharyngeal and oropharyngeal swab samples in 1006 PCV13 recipients and 1005 controls. Serotyping of the 13 vaccine-type (VT) pneumococci was performed by PCR targeting capsular synthesis genes and Quellung reaction of isolates.

Results

Before randomization and based on PCR, 339 of 1891 subjects had nasopharyngeal carriage with any pneumococci (17.9%), and 114 of 1891 (6.0%) carried VT pneumococci. At 6 months after vaccination, VT pneumococcal carriage was significantly lower in PCV13 recipients than in the placebo group (relative risk, 0.53; 95% confidence interval, .35-.80; P = .04). There was no difference between the groups at 12 and 24 months after vaccination. Carriage of non-VT pneumococci, S. aureus, H. influenzae, and M. catarrhalis did not change between groups.

Conclusions

In community-dwelling adults aged ≥65 years, a single dose of PCV13 seems to elicit a small and temporary reduction in VT carriage 6 months after vaccination. Neither replacement by non-VT serotypes nor impact on other nasopharyngeal bacteria was observed.

Hospital-onset adult invasive pneumococcal disease in Israel: Sicker patients, different pathogens

OBJECTIVES

Invasive pneumococcal disease (IPD) usually has its onset in the community (CO-IPD), but it can commence following hospitalization (HO-IPD). This study compared HO-IPD and CO-IPD cases during the implementation of the pneumococcal conjugate vaccine (PCV) program for children in Israel.

METHODS

This was a nationwide retrospective cohort study of adult (age >18 years) IPD patients covering the period from the implementation of the PCV7/13 program in 2009/2010 through 2015. HO-IPD and CO-IPD were defined as IPD with onset ≥4 and ≤2 days from admission, respectively. Patient characteristics, outcome measures, serotypes, and antimicrobial susceptibility were compared for the entire cohort, followed by a matched case-control analysis.

RESULTS

The study included 114 patients with HO-IPD and 2180 with CO-IPD. After matching HO-IPD to CO-IPD patients by age, sex, and comorbidities, the mortality rate and discharge to long-term care facility rate were significantly higher for HO-IPD patients than for CO-IPD patients (44.6% vs. 26.3% and 26.5% vs. 8.2%, respectively). HO-IPD isolates were less often covered by PCV13 (39.6% vs. 49.0%) and pneumococcal polysaccharide vaccine PPSV23 (56.6% vs. 71.3%) and more often resistant to penicillin (9.3% vs. 3.6%), ceftriaxone (3.8% vs. 0.75%), and levofloxacin (9.3% vs. 0.8%).

CONCLUSIONS

HO-IPD was associated with higher morbidity and mortality than CO-IPD and was more often caused by non-vaccine serotypes (primarily non-PCV13 types) and antibiotic-resistant strains.

Persistence of antibodies 1 year after sequential administration of the 13-valent pneumococcal conjugate vaccine and the 23-valent pneumococcal polysaccharide vaccine in adults

Vaccination with the 13-valent pneumococcal conjugate vaccine (PCV13) followed ≥ 1 year by the 23-valent pneumococcal polysaccharide vaccine (PPSV23) is recommended for immunocompetent adults ≥ 65 years of age in the United States. This study assessed antipneumococcal opsonophagocytic activity (OPA) geometric mean titers (GMTs) to PCV13 in PPSV23-naive and PPSV23-preimmunized adults 1 year after a second vaccine dose. Two parent studies were conducted previously: (1) PPSV23 vaccine–naive subjects (60–64 years of age at enrollment) received PCV13 followed by PCV13 or PPSV23 1 year later or PPSV23 followed by PCV13 1 year later; and (2) subjects (≥ 70 years of age at enrollment) vaccinated with PPSV23 ≥ 5 years before study entry received PCV13 or PPSV23 followed by PCV13 1 year later. Overall, 962 subjects (PPSV23-naive, n = 519; PPSV23-preimmunized, n = 443) who received both vaccinations in the parent studies were enrolled. Numerically higher OPA GMTs persisted for at least 1 year after administration of PCV13 as the initial vaccine (PCV13/PPSV23 or PCV13/PCV13) compared with those who received PPSV23 either 1 or 5 years prior (PPSV23/PCV13). This impairment in antibody responses to subsequent PCV13 vaccination produced by initial PPSV23 vaccination persisted for at least 1 year. OPA GMTs were numerically higher for most serotypes 1 year after 2 doses of PCV13 compared with 1 year after the first PCV13 dose. These data suggest PCV13 should be given first if both vaccines are to be administered, higher immune responses were achieved when PCV13 was given first and persisted at least 1 year (ClinicalTrials.gov Identifier: NCT01025336).

Adult invasive pneumococcal disease in the Republic of Korea: Risk medical conditions and mortality stratified by age group

OBJECTIVES

This study aimed to characterize the risk factors for mortality in adult patients with invasive pneumococcal disease (IPD) stratified by age groups, after implementation of the national immunization program of 23-valent polysaccharide vaccine (PPSV23) for those aged ≥65 years in the Republic of Korea (ROK).

METHODS

Clinical data and pneumococcal isolates from adult patients with IPD (≥18 years of age) were collected prospectively from 20 hospitals through the nationwide surveillance program from March 2013 to October 2015.

RESULTS

A total of 319 patients with IPD were enrolled. Median age was 69 years. Overall in-hospital mortality was 34.2%: 17.1% in those aged 18-49 years, 23.7% in those aged 50-64 years, 33.0% in those aged 65-74 years, and 51.0% in those aged ≥75 years (p<0.001). In particular, early death within 7days of hospitalization accounted for 60.6% (66/109). While old age (≥65 years), higher Pitt bacteremia score (≥4), and bacteremic pneumonia were independently associated with IPD mortality in all age groups, an additional mortality risk factor of immunocompromised status was identified for patients aged 50-64 years. PPSV23 serotypes accounted for 64.4% (122/189) of the pneumococcal isolates serotyped.

CONCLUSIONS

This study suggests that vaccine-type IPD continues to place a substantial burden on older adults in the ROK, necessitating an effective vaccination strategy for those at higher risk.

Incidence rate of community-acquired pneumonia in adults: a population-based prospective active surveillance study in three cities in South America

OBJECTIVE

To determine the incidence rate and mortality of community-acquired pneumonia (CAP) in adults in three cities in Latin America during a 3-year period.

DESIGN

Prospective population-based surveillance study.

SETTING

Healthcare facilities (outpatient centres and hospitals) in the cities of General Roca (Argentina), Rivera (Uruguay) and Concepción (Paraguay).

PARTICIPANTS

2302 adults aged 18 years and older with CAP were prospectively enrolled between January 2012 and March 2015.

MAIN OUTCOME MEASURES

Incidence rates of CAP in adults, predisposing conditions for disease, mortality at 14 days and at 1 year were estimated. Incidence rate of CAP, within each age group, was calculated by dividing the number of cases by the person-years of disease-free exposure time based on the last census; incidence rates were expressed per 1000 person-years.

RESULTS

Median age of participants was 66 years, 46.44% were men, 68% were hospitalised. Annual incidence rate was 7.03 (95% CI 6.64 to 7.44) per 1000 person-years in General Roca, 6.33 (95% CI 5.92 to 6.78) per 1000 person-years in Rivera and 1.76 (95% CI 1.55 to 2.00) per 1000 person-years in Concepción. Incidence rates were highest in participants aged over 65 years. 82.4% had at least one predisposing condition and 48% had two or more (multimorbidity). Chronic heart disease (43.6%) and smoking (37.3%) were the most common risk factors. 14-day mortality rate was 12.1% and 1-year mortality was 24.9%. Multimorbidity was associated with an increased risk of death at 14 days (OR 2.91; 95% CI 2.23 to 3.80) and at 1 year (OR 3.00; 95% CI 2.44 to 3.70).

CONCLUSIONS

We found a high incidence rate of CAP in adults, ranging from 1.76 to 7.03 per 1000 person-years, in three cities in South America, disclosing the high burden of disease in the region. Efforts to improve prevention strategies are needed.

[Immunizing is not only a children's matter! : Why vaccinations are also important for adults]

Vaccinations belong to the ten most effective public health achievements worldwide. While immunization programms for children are installed in Europe, vaccinations for adults are not established. However, adult vaccination is extremely meaningful: increasing age means a higher susceptibility to infectious diseases, health problems and multimorbidity will increase. The burden of vaccine-preventable diseases is still high in Europe. Due to immunosenescence (older) adults are less protected against pathogens, antibody titers after vaccinations are lower and immunity lasts shorter. There is striking lack of data of adult vaccination rates and an international consensus regarding adult vaccination recommendations or guidelines are not available in Europe. In only six countries a comprehensive document describing recommended vaccinations for adults is available, among them Austria. The awareness of the importance of adult vaccination over the whole lifetime is not present to the necessary extent in Europe and has to be promoted.

Immunogenicity, Safety and Reactogenicity of a Booster Dose of the 10-Valent Pneumococcal Nontypeable H. influenzae Protein D Conjugate Vaccine Coadministered With DTPa-IPV-Hib in Dutch Children: A Randomized Controlled Trial

BACKGROUND

Immune responses and safety profiles may be affected when vaccines are coadministered. We evaluated the immunogenicity, safety and reactogenicity of a booster dose of the 10-valent pneumococcal nontypeable Haemophilus influenzae protein D-conjugate (PHiD-CV; Synflorix GSK Vaccines) and DTPa-IPV-Hib (Pediacel Sanofi Pasteur MSD) when coadministered.

METHODS

We performed booster assessment in a randomized controlled trial in the Netherlands. Of 780 enrolled healthy infants, 774 toddlers participated in the booster phase and received (1:1:1) (1) PHiD-CV + DTPa-HBV-IPV/Hib (Infanrix hexa, GSK Vaccines), (2) PHiD-CV + DTPa-IPV-Hib, or (3) 7-valent pneumococcal conjugate vaccine (7vCRM, Prevenar/Prevnar, Pfizer, Inc.) + DTPa-IPV-Hib at 2, 3, 4 and 11-13 months old. Blood samples were taken postprimary, prebooster, 1 and 12 months postbooster.

RESULTS

Antipneumococcal antibody responses were comparable between both PHiD-CV groups, except for serotype 18C (conjugated to tetanus toxoid). Anti-18C antibody geometric mean concentrations (GMCs) were higher when coadministered with DTPa-HBV-IPV/Hib. For each vaccine serotype, the percentages of children with antibody concentration ≥ 0.20 μg/mL were within the same ranges between PHiD-CV groups (93.8%-100%). The same was observed for the percentages of participants with opsonophagocytic activity titer ≥ 8 (90.9%-100%). When comparing both DTPa-IPV-Hib groups, postbooster antidiphtheria antibody GMCs were higher when coadministered with 7vCRM, while antitetanus and antipolyribosyl-ribitol phosphate antibody GMCs were higher with PHiD-CV coadministration. Regardless, antibody levels to these antigens were well above thresholds. Safety and reactogenicity profiles were comparable between groups.

CONCLUSIONS

Coadministration of a booster dose of PHiD-CV and DTPa-IPV-Hib was immunogenic and well tolerated.

Pneumococcal conjugate vaccine herd effects on non-invasive pneumococcal pneumonia in elderly

BACKGROUND

Herd protection from infant pneumococcal conjugate vaccination is well established for invasive pneumococcal disease (IPD) but not for non-IPD pneumococcal community-acquired pneumonia (PCAP). We assessed the contribution of vaccine-serotypes in non-IPD PCAP in adults 65 years and older in the period 2008-2013.

METHODS

This is a post hoc analysis of two prospective studies from the Netherlands. Serotype specific urinary antigen detection and routine microbiological testing were used to categorize episodes as IPD or non-IPD PCAP caused by 7-valent pneumococcal conjugate vaccine (PCV7), PCV10-7 (three additional PCV10 serotypes), PCV13-10 (three additional PCV13 serotypes), and non-PCV13 serotypes. Proportions per vaccine-serotype group were assessed per year from June 1st to May 31st. Time trends were compared to national IPD data.

RESULTS

Of 270 non-IPD PCAP episodes with known serotype, PCV7 serotypes decreased from 28% in 2008/2009 to 7% in 2012/2013 (p-value for trend <0.001). No change in PCV10-7 (19% overall) and PCV13-10 (29% overall) serotypes was observed. Non-PCV13 serotypes increased from 30% in 2008/2009 to 37% in 2012/2013 (p-value for trend 0.048). Trends corresponded with national IPD data.

CONCLUSION

PCV7 serotypes declined in non-IPD PCAP among elderly between 2008 and 2013, comparable to IPD data. No reduction in the additional PCV10 serotypes could be demonstrated within the first two years after PCV10 introduction.

Immunogenicity and safety of a second administration of 13-valent pneumococcal conjugate vaccine 5 years after initial vaccination in adults 50 years and older

BACKGROUND

Vaccination effectively reduces invasive disease and pneumonia caused by Streptococcus pneumoniae. However, waning antibody titers and the ability of revaccination to boost titers in older adults have been concerns. A study to describe antibody persistence after vaccination with 13-valent pneumococcal conjugate vaccine (PCV13) and response to revaccination 5 years after the initial dose was conducted.

METHODS

Pneumococcal vaccine-naive subjects aged 50-59 years were randomized and vaccinated with PCV13 plus trivalent inactivated influenza vaccine concomitantly or 1 month apart, then revaccinated with PCV13 five years later. Antipneumococcal polysaccharide opsonophagocytic activity (OPA) geometric mean titers (GMTs) and immunoglobulin G (IgG) geometric mean concentrations (GMCs) were determined before and approximately 1 month after each vaccination. Targeted local reactions and systemic events were collected for 14 days, adverse events (AEs) for 1 month, and serious AEs (SAEs) for 6 months after each vaccination.

RESULTS

Of 1116 randomized subjects, 727 were revaccinated at year 5. Between the time of initial vaccination and revaccination, OPA GMTs and IgG GMCs declined but remained higher than levels before initial vaccination for 12 of the 13 vaccine serotypes. One month after revaccination, OPA GMTs and IgG GMCs were comparable with, or higher than, levels observed 1 month after initial vaccination for most vaccine serotypes. Local reactions were mostly mild. AEs were reported by <5% and SAEs by <1% of subjects at 1 and 6 months after revaccination, respectively. No SAEs were vaccine-related.

CONCLUSIONS

Revaccination of adults ≥50 years with PCV13 five years after primary vaccination was safe and immunogenic. Additionally, antibody titers were maintained for at least 5 years after vaccination. The vaccine stimulated a memory response as shown by enhanced responses that were maintained or enhanced by revaccination. CLINICALTRIALS.

GOV REGISTRATION

NCT00521586.

The role of the local microbial ecosystem in respiratory health and disease

Respiratory tract infections are a major global health concern, accounting for high morbidity and mortality, especially in young children and elderly individuals. Traditionally, highly common bacterial respiratory tract infections, including otitis media and pneumonia, were thought to be caused by a limited number of pathogens including Streptococcus pneumoniae and Haemophilus influenzae. However, these pathogens are also frequently observed commensal residents of the upper respiratory tract (URT) and form-together with harmless commensal bacteria, viruses and fungi-intricate ecological networks, collectively known as the 'microbiome'. Analogous to the gut microbiome, the respiratory microbiome at equilibrium is thought to be beneficial to the host by priming the immune system and providing colonization resistance, while an imbalanced ecosystem might predispose to bacterial overgrowth and development of respiratory infections. We postulate that specific ecological perturbations of the bacterial communities in the URT can occur in response to various lifestyle or environmental effectors, leading to diminished colonization resistance, loss of containment of newly acquired or resident pathogens, preluding bacterial overgrowth, ultimately resulting in local or systemic bacterial infections. Here, we review the current body of literature regarding niche-specific upper respiratory microbiota profiles within human hosts and the changes occurring within these profiles that are associated with respiratory infections.

Molecular surveillance of nasopharyngeal carriage of Streptococcus pneumoniae in children vaccinated with conjugated polysaccharide pneumococcal vaccines

Following the introduction of pneumococcal conjugate vaccines (PCVs) for infants, surveillance studies on Streptococcus pneumoniae carriage have proven valuable for monitoring vaccine effects. Here, we compared molecular versus conventional diagnostic methods in prospective cross-sectional surveillances in vaccinated infants in the Netherlands. Nasopharyngeal samples (n = 1169) from 11- and 24-month-old children, collected during autumn/winter 2010/2011 and 2012/2013, were tested by conventional culture for S. pneumoniae. DNA extracted from all culture-plate growth was tested by qPCR for pneumococcal-specific genes (lytA/piaB) and selected serotypes (including PCV13-serotypes). qPCR significantly increased the number of carriers detected compared to culture (69% vs. 57%, p < 0.0001). qPCR assays targeting vaccine-serotypes 4 and 5 proved non-specific (results excluded). For serotypes reliably targeted by qPCR, the number of serotype-carriage events detected by qPCR (n = 709) was 1.68× higher compared to culture (n = 422). There was a strong correlation (rho = 0.980; p < 0.0001) between the number of serotypes detected using qPCR and by culture. This study demonstrates the high potential of molecular methods in pneumococcal surveillances, particularly for enhanced serotype detection. We found no evidence of a hidden circulation of vaccine-targeted serotypes, despite vaccine-serotypes still significantly contributing to invasive pneumococcal disease in unvaccinated individuals, supporting the presence of a substantial S. pneumoniae reservoir outside vaccinated children.

Advances in the prevention, management, and treatment of community-acquired pneumonia

Community-acquired pneumonia (CAP) is the infectious disease with the highest number of deaths worldwide. Nevertheless, its importance is often underestimated. Large cohorts of patients with CAP have been established worldwide and improved our knowledge about CAP by far. Therefore, current guidelines are much more evidence-based than ever before. This article discusses recent major studies and concepts on CAP such as the role of biomarkers, appropriate risk stratification to identify patients in need of hospitalisation or intensive care, appropriate empiric antibiotic therapy (including the impact of macrolide combination therapy and antibiotic stewardship), and CAP prevention with novel influenza and pneumococcal vaccines.

Burden of four vaccine preventable diseases in older adults

BACKGROUND

Implementation of additional targeted vaccinations to prevent infectious diseases in the older adults is under discussion in different countries. When considering the added value of such preventive measures, insight into the current disease burden will assist in prioritization. The aim of this study was derive the first estimates of the disease burden in adults aged 50 years or over in the Netherlands for influenza, pertussis, pneumococcal disease and herpes zoster.

METHODS

The average annual disease burden for these four diseases in the Netherlands was calculated for the period 2010-2013 using the disability-adjusted life years (DALY) measure. Disease models and parameters were obtained from previous research. Where possible we adapted these models specifically for older adults and applied age-specific parameters derived from literature. The disease burden based on these adapted models and parameters was compared with the disease burden based on the general population models.

RESULTS

The estimated average annual disease burden was from high to low: pneumococcal disease (37,223 DALYs/year), influenza (7941 DALYs/year), herpes zoster (942 DALYs/year), and pertussis (812 DALYs/year). The adaptation of models and parameters specifically for the elderly resulted in a higher disease burden compared to the use of general population models.

CONCLUSIONS

Among older adults, the disease burden in the period 2010-2013 was highest for pneumococcal disease, mostly because of high mortality, followed by influenza. Disease burden of herpes zoster and pertussis was relatively low and consisted mostly of years lived with disability. Better information on the course of infectious diseases and long-term consequences would enable more accurate estimation of disease burden in older adults.

Carriage of Streptococcus pneumoniae in asymptomatic, community-dwelling elderly in the Netherlands

Colonization of the upper respiratory tract by Streptococcus pneumoniae is considered prerequisite for pneumococcal disease. Despite high rates of pneumococcal disease in elderly, pneumococcal carriage rates are usually below 5% when detected by the conventional culture method. We assessed pneumococcal carriage in 330 asymptomatic community-dwelling elderly aged 65 years and older. While pneumococci were cultured from 25 (8%) individuals, 65 (20%) elderly were positive for the pneumococcus-specific lytA gene when tested by quantitative-PCR, increasing the overall number of carriers to 75 (22%). Significantly more oropharyngeal samples were pneumococci-positive (18% versus 10%, p<0.001) when tested by the molecular method as compared to nasopharyngeal samples. Our findings indicate that pneumococcal carriage in elderly is higher than previously reported with up to 1 in 5 asymptomatic community-dwelling elderly positive for pneumococcal carriage, when detected by qPCR. The detection of pneumococci by conventional culture alone, greatly underestimates S. pneumoniae colonization in elderly.

The role of the local microbial ecosystem in respiratory health and disease

Respiratory tract infections are a major global health concern, accounting for high morbidity and mortality, especially in young children and elderly individuals. Traditionally, highly common bacterial respiratory tract infections, including otitis media and pneumonia, were thought to be caused by a limited number of pathogens including Streptococcus pneumoniae and Haemophilus influenzae. However, these pathogens are also frequently observed commensal residents of the upper respiratory tract (URT) and form-together with harmless commensal bacteria, viruses and fungi-intricate ecological networks, collectively known as the 'microbiome'. Analogous to the gut microbiome, the respiratory microbiome at equilibrium is thought to be beneficial to the host by priming the immune system and providing colonization resistance, while an imbalanced ecosystem might predispose to bacterial overgrowth and development of respiratory infections. We postulate that specific ecological perturbations of the bacterial communities in the URT can occur in response to various lifestyle or environmental effectors, leading to diminished colonization resistance, loss of containment of newly acquired or resident pathogens, preluding bacterial overgrowth, ultimately resulting in local or systemic bacterial infections. Here, we review the current body of literature regarding niche-specific upper respiratory microbiota profiles within human hosts and the changes occurring within these profiles that are associated with respiratory infections.

A few years later. Update of the cost-effectiveness of infant pneumococcal vaccination in Dutch children

This study aimed to calculate the cost-effectiveness of infant pneumococcal vaccination in the Netherlands, using the 13-valent PCV13 vs. the currently used 10-valent PCV10. We adapted a previously published model, using recent estimates of epidemiological and efficacy data. In 12 scenarios, we explored the impact of different assumptions on the incremental cost-effectiveness ratio (ICER) of PCV13 over PCV10.Taking only direct effects on invasive pneumococcal disease into account, PCV13 was not found to be cost-effective at a price difference of €11 per dose. If herd protection, replacement and non-invasive disease were also taken into account, the ICER of PCV13 compared with PCV10 was below €30 000/QALY gained in 11 of 12 scenarios. PCV13 was considered dominant in the primary scenario with a price difference below €2.63 per dose.

Disease Burden of Invasive Meningococcal Disease in the Netherlands Between June 1999 and June 2011: A Subjective Role for Serogroup and Clonal Complex

BACKGROUND

Several countries consider the implementation of a meningococcal serogroup B vaccine for young children and/or serogroup C or ACWY conjugate vaccine for adolescents. Representative information on clinical course of invasive meningococcal disease (IMD) is useful to evaluate cost-effectiveness of vaccination. Information on the relation between infecting meningococcal clonal complex (CC), disease course and outcome of IMD is scarce.

METHODS

A retrospective study using Dutch surveillance data on IMD from June 1999 to June 2011. Clinical information was retrieved from hospital records. The effect of age, comorbidity, clinical manifestation, serogroup, and CC on disease course and outcome was assessed in multivariable analyses. Meningococcal CCs were assessed by multilocus sequence typing.

RESULTS

Clinical information was retrieved for 879 IMD cases: 48% of patients presented with meningitis, 17% with septic shock, and 22% with septic shock plus meningitis. Development of septic shock was not related to CC or serogroup. Median (interquartile range) duration of hospital admission was 10 (8-13) days. Intensive care unit admittance (38%) was higher for patients aged ≥10 years and patients with septic shock (P-values ≤.001). Case-fatality rate (8%) and development of sequelae (29%) was dependent on age and clinical manifestation (P-values ≤.001) and not affected by comorbidity, CC, or serogroup.

CONCLUSIONS

IMD still coincides with a considerable disease burden and mortality. Disease course and outcome depend mainly on age and clinical manifestation and less on meningococcal CC or serogroup.

Clinical burden of pneumonia, meningitis and septicemia in Norway 2 years after 7-valent pneumococcal conjugate vaccine introduction

AIMS

This population-based, retrospective study quantified the rates of all-cause and pneumococcal pneumonia, meningitis and septicemia in Norway from 2008 to 2009 and determined the proportions of cases caused by pneumococcal vaccine serotypes.

METHODS

Data on patients with all-cause and pneumococcal pneumonia, meningitis and septicemia were obtained from the Norwegian Patient Registry, which collects hospitalization data from all Norwegian public hospitals based on International Classification of Diseases codes. Norwegian Patient Registry case records linked to the Norwegian Surveillance System for Communicable Diseases provided serotype data for invasive pneumococcal disease in patients with microbiological cultures.

RESULTS

In 2008 and 2009, hospitalization rates were relatively stable for all-cause pneumonia (5.28 and 5.35, respectively, per 1000), meningitis (10.70 and 9.67, respectively, per 100,000), and septicemia (from 171.81 to 161.46 per 100,000). In contrast, rates decreased for International Classification of Diseases-10 diagnosed pneumococcal pneumonia (from 13.66 to 10.52 per 100,000), although these cases may be under-reported because of inclusion in all-cause pneumonia. Rates also decreased in diagnosed pneumococcal meningitis (from 1.60 to 1.19 per 100,000) and diagnosed pneumococcal septicemia (from 9.08 to 7.94 per 100,000). Diagnosed pneumococcal disease rates were highest in younger children and older adults, peaking at ⩾ 60 years old. Pneumococcal pneumonia, meningitis and septicemia caused by serotypes included in the 7-valent pneumococcal conjugate vaccine decreased substantially during the study period, with corresponding serotype replacement by non-7-valent pneumococcal conjugate vaccine serotypes.

CONCLUSIONS

From 2008 to 2009, International Classification of Diseases-10 diagnosed pneumococcal pneumonia, meningitis and septicemia decreased in most age groups but remained greatest among subjects aged 0-1 and ⩾ 60 years.

Vaccination in the elderly: what can be recommended?

The age-associated increased susceptibility to infectious disease would suggest that vaccination should be a route to promote healthy aging and keep our seniors autonomous and independent. While vaccination represents a cost-effective and efficient strategy at community level, the ability of the immune system to mount a protective immune response is still unpredictable at the level of the individual. Thus, at a similar age, some individuals, including the elderly, might still be 'good' responders while some other, even younger, would definitely fail to mount a protective response. In this review, the current burden of vaccine-preventable diseases in the aging and aged population will be detailed with the aim to identify the ideal vaccine candidates over the age of 50 years. This article will conclude with potential strategies to reduce, as best as possible, this burden and the imperative need to overcome barriers in extending current vaccine coverage towards to a lifelong vaccine schedule.

Pneumococcal vaccination: what have we learnt so far and what can we expect in the future?

Individuals <2 years and ≥50 years of age, as well as those with other specific risk factors, are especially vulnerable to invasive pneumococcal disease (IPD). Conjugate vaccines have been developed against encapsulated bacteria such as Streptococcus pneumoniae to provide improved immune responses. The 7-valent pneumococcal conjugate vaccine (PCV7) has significantly reduced the burden of vaccine-type pneumococcal diseases in children, including invasive disease and pneumonia and acute otitis media. There have also been significant declines in antimicrobial resistance in 7-valent vaccine serotypes and carriage of S. pneumoniae in the post-PCV7 era. Two to three years after the introduction of PCV13, there is emerging, global evidence of a reduced burden of pneumococcal diseases in children, including declines in IPD (UK and Germany) and nasopharyngeal carriage of PCV13 serotypes (Portugal and France). The functional immunogenicity of PCV13 in individuals ≥50 years of age has been demonstrated in clinical trials in comparison with the 23-valent pneumococcal polysaccharide vaccine and for children and adults 6 to 49 years of age. Between 2011 and 2013, PCV13 received market authorisation by the European Medicines Agency (EMA) for these additional age groups and is now available in Europe for the prevention of pneumococcal disease in all age groups.

Epidemiology and outcome of invasive pneumococcal disease among adults in Belgium, 2009-2011

This epidemiological study examined morbidity and case fatality of invasive pneumococcal disease (IPD) in adults in Belgium as well as distribution and antibiotic susceptibility of Streptococcus pneumoniae serotypes.Adults hospitalised with microbiologically proven IPD were prospectively enrolled. The study started in 2009 with patients aged ≥50 years, whereas in 2010 and 2011, patients aged ≥18 years were included. The clinical presentation, patient profile, treatment, outcome, and mortality were recorded during hospitalisation.Outcome was also assessed one month afterdischarge. Of the 1,875 patients with IPD identified, 1,332 were included in the analysis. Bacteraemic pneumonia, affecting 1,049 of the patients, was the most frequent IPD type (79%), and chronic obstructive pulmonary disease and cancer were the main comorbidities.One-third of patients required admission to intensive care unit. A total of 208 (16%) patients died during hospitalisation and an additional 21 (2%) within one month after discharge. Case fatality rates of ≥20%were observed in patients with chronic heart failure, hepatic disease, and renal insufficiency. Serotypes 7F, 1, 19A, and 3 were the most prevalent and together accounted for 47% (569/1,214) of all IPD cases and 42% (80/189) of mortality. Of the patient isolates, 21% (255/1,204) were resistant to erythromycin and 22% (264/1,204) to tetracycline. Penicillin non-susceptibility was mostly found in serotype 19A isolates. These baseline data are essential when assessing the impact of pneumococcal conjugate vaccination in adults in the future.

Serious infections in systemic lupus erythematosus with a focus on pneumococcal infections

Background

Infections are important denominators of morbidity and mortality in patients with systemic lupus erythematosus (SLE). Pneumococcus pneumoniae has been identified as a relatively frequent cause of serious infections in SLE and vaccination against this pathogen is possible. We analysed the incidence of serious infections in a cohort of SLE patients, focussing on Streptococcus pneumoniae.

Methods

We retrospectively screened the medical records of all SLE patients who were regularly seen in the outpatient clinic of our department between January 2010 and December 2012. We registered all infections that necessitated admission to the hospital (serious infection) and compared relevant clinical and laboratory parameters and immunomodulating/immunosuppressive treatment in patients with and without serious infections.

Results

In the total cohort of 260 patients, there were 132 episodes of serious infection in 70 patients, with a median follow-up per patient of 11.4 years (range 0 to 50.2 years). S. pneumoniae accounted for 11/132 (8.3%) serious infection episodes and eight of 11 episodes were invasive. With a follow-up of 3970.6 years for the total cohort, this leads to an incidence of 201/100.000 patient-years. In the multivariate analysis neither clinical parameters nor use of immunosuppressive drugs correlated with occurrence of serious infections.

Conclusions

Compared to the incidence of invasive pneumococcal infections in the Dutch population (15.6/100.000 patient years), the incidence in SLE patients is 13 times higher. This, in combination with the absence of a relation to use of immunosuppressive drugs, is a strong argument to recommend vaccination against S. pneumoniae in all SLE patients.

Consensus document for the prevention of respiratory infections in adults

Infectious diseases are one of the principle causes of morbidity, mortality and drain on health resources worldwide. In recent years there has been an increase in the impact of respiratory infections, particularly in the Portuguese population. It is for this reason that the Portuguese Respiratory Society has presented a series of recommendations for the prevention of respiratory infections in adults. These recommendations include both general measures and vaccinations for flu and pneumococcal pneumonia.

Cost effectiveness of the new pneumococcal vaccines: a systematic review of European studies

INTRODUCTION

Diseases caused by Streptococcus pneumoniae (pneumococcus) are a major global public health problem. Despite their importance, information on the burden of the different pneumococcal diseases is limited and estimates vary widely.

OBJECTIVE AND METHODS

We critically reviewed the full economic evaluations (FEEs) on the new pneumococcal conjugate vaccines (PCVs) conducted in the European Union (EU) to assess their potential contribution to public decision making. We selected the FEEs focussed on PCV-10 and PCV-13 and published in English from January 2007 until June 2013. We screened the selected articles to assess their main methodological features using a common checklist composed of epidemiological, clinical and economic items.

RESULTS

All the ten studies selected were based on modelling and the time horizon was always long term. Two studies focused on adults, the remaining eight on infants. Only one study based herd immunity on national data, eight used foreign data or modelling and the last did not consider it. National prices and tariffs were claimed to be sources for unit costs in all studies; however, half of them assumed price parity when one vaccine was not yet marketed, and the figures varied within the countries where more than one study was conducted. Conclusions supported the economic utility of pneumococcal vaccination in all studies, raising some concern only in (i) the independent study, which found that PCV-13 was borderline cost effective, and (ii) the study sponsored by both manufacturers, which estimated an incremental ratio slightly above the national threshold for both PCV-10 and PCV-13.

CONCLUSION

The European studies we analysed are mostly based on weak sources of data. Because of the limited information on vaccine effectiveness and lack of epidemiological and economic data, the need for extensive recourse to assumptions leads to great within- and between-study variability generated by authors' choices.

Assessment of vaccine candidates for persons aged 50 and older: a review

BACKGROUND

The increasing life expectancy in most European countries has resulted in growth of the population 50 and older. This population is more susceptible to infectious diseases because of immunosenescence, co-morbidity and general frailty. Thus, to promote healthy aging, vaccination against vaccine-preventable-diseases could be one strategy. In addition to its possible individual benefits, vaccination may also yield social benefits, such as a lower overall cost of healthcare. Most European countries, however, offer only influenza vaccine although vaccines for pneumococcal disease, herpes zoster, pertussis, and hepatitis A are also available. Our aim is to review the knowledge of these vaccines for persons aged 50 and older and explore the arguments for expanding current vaccination programmes beyond just influenza.

METHODS

The evaluation model of Kimman et al. was used to assess herpes zoster, pneumococcal disease, pertussis and hepatitis A in terms of four domains: pathogen, vaccine, disease outcomes and cost-effectiveness. The sources were Dutch surveillance systems, seroprevalence studies and the international literature.

RESULTS

Herpes zoster, pneumococcal disease and pertussis are prevalent among persons aged 50 and older. Vaccines vary in effectiveness and have mild and self-limiting side effects. Vaccination against pneumococcal disease and pertussis causes adaptation of the responsible pathogen. For pertussis and hepatitis A, the vaccine is not registered specifically for the elderly population. Vaccination against herpes zoster and pertussis could improve quality of life, while vaccination against pneumococcal disease and hepatitis A prevents mortality. However, only vaccination against herpes zoster and pneumococcal disease appear to be cost-effective.

CONCLUSIONS

Vaccination can improve the health of the elderly population. As our review shows, however, the data are too incomplete to accurately judge its potential impact. More research is needed to determine how vaccination can most effectively improve the health of the growing population 50 years and older.

Invasive pneumococcal disease and 7-valent pneumococcal conjugate vaccine, the Netherlands

Disease incidence and case fatality rates declined 4 years after introduction of the vaccine.

Pneumococcal infection--low awareness as a potential barrier to vaccination: results of a European study

INTRODUCTION

Elderly people and adults with chronic disease or compromised immune status are at increased risk of pneumococcal infection, with pneumonia being the most common serious presentation and a significant cause of morbidity and mortality. Most European countries have recommendations for pneumococcal vaccination but vaccination rates have remained low. In the present article, the authors present the results of a European survey that investigated the current level of awareness of pneumococcal infection among primary care physicians and specialists, and attitudes to vaccination in these physicians and members of the general public aged >50 years.

METHODS

Primary care physicians (n = 1,300) and specialists (n = 926) from 13 Western European countries participated in online/face-to-face interviews, and a further 6,534 individuals aged >50 years from a population sample reflecting local socio-demographic structure participated in telephone/face-to-face interviews.

RESULTS

Pneumonia was the most well-known of the pneumococcal infections amongst primary care physicians and specialists. However, there was a relatively low awareness of the term invasive pneumococcal disease (IPD), with only 50% of primary care physicians and 71% of specialists reporting knowledge of the term IPD. Key factors influencing a physician's decision to prescribe pneumococcal vaccination were the patient's health condition, recommendations from health authorities, and the tolerability of the vaccine. Perceptions regarding vaccination were good amongst the members of the general public; individuals did not fear vaccines or their side effects. The main drivers for vaccination were recommendations from a healthcare professional and, to a lesser extent, that vaccination provides reassurance against contracting a disease.

CONCLUSION

These findings highlight the low awareness of the term IPD in comparison with individual pneumococcal conditions. Given the importance of physician recommendations in encouraging patients to be vaccinated, primary care physicians need to be vigilant of patients at risk of pneumococcal infections in order to increase vaccination rates.

Pneumococcal 13-valent conjugate vaccine for the prevention of invasive pneumococcal disease in children and adults

Pneumococcal disease remains a global problem despite the availability of effective conjugate vaccines. The 13-valent pneumococcal conjugate vaccine (PCV13) extends the valency of PCV7 by including six additional serotypes highly associated with invasive pneumococcal disease (IPD). Comparisons between PCV13 and PCV7 or the pneumococcal polysaccharide vaccine have established noninferiority of PCV13 for both safety and immunogenicity profiles for use in children and adults, respectively. At the end of 2011, PCV13 had been approved and launched in 104 countries worldwide, with 54 including the vaccine in their pediatric national immunization program. Surveillance data from early adopters of PCV13 has indicated reductions are occurring in both overall IPD and IPD caused by the six non-PCV7 serotypes; early reports of serotype replacement in carriage are also emerging. While serotype replacement for PCV7 was observed to varying degrees for both carriage and disease, the extent to which this will occur for PCV13 is yet to be determined.

Cost-effectiveness of vaccinating adults with the 23-valent pneumococcal polysaccharide vaccine (PPV23) in Germany

The introduction of routine infant vaccination against pneumococcal disease has resulted in a decreased overall invasive pneumococcal disease incidence in adults but also a change in invasive pneumococcal disease serotypes. This study aimed to assess the cost-effectiveness of 23-valent pneumococcal polysaccharide vaccine (PPV23) in Germany in this context. A population-based Markov model was developed. A cohort of adults currently eligible for vaccination was followed until death. Adult vaccination with PPV23 was associated with an incremental cost-effectiveness ratio of €17,065/quality-adjusted life years gained from the third-party payer's perspective. Univariate sensitivity analyses showed that the incremental cost-effectiveness ratio was below €50,000/quality-adjusted life years gained in most test scenarios. The model suggests that adult PPV23 vaccination is cost effective in Germany, due to its broad serotype coverage. This is despite epidemiological changes in Streptococcus pneumoniae serotypes caused by wider use of pneumococcal conjugate vaccines during childhood.

A public health and budget impact analysis of vaccinating at-risk adults and the elderly against pneumococcal diseases in Germany

To assess the comparative public health and budget impact over 5 years of several pneumococcal vaccination strategies (23-valent pneumococcal polysaccharide vaccine [PPV23] and/or 13-valent pneumococcal conjugate vaccine [PCV13]) in Germany, within the context of changing invasive pneumococcal disease (IPD) incidence over time. A multi-cohort, population-based Markov model was developed. Uncertainty around vaccine effectiveness, costs and IPD incidence change was handled through scenario analyses. Between 2012 and 2016, the introduction of PCV13 in adults, compared with the use of PPV23, would be associated with a net estimated budget increase of €59.7 million (+6.7%) to €151.6 million (+13.7%). Impact on IPD incidence ranged from -113 cases (-0.8%) to +298 cases (+2.8%). Introducing PCV13 in adults is expected to significantly affect healthcare budgets. Adult vaccination with PPV23 remains the optimal vaccination strategy from public health and budget perspectives.

Validation of an immunodiagnostic assay for detection of 13 Streptococcus pneumoniae serotype-specific polysaccharides in human urine

To improve the clinical diagnosis of pneumococcal infection in bacteremic and nonbacteremic community-acquired pneumonia (CAP), a Luminex technology-based multiplex urinary antigen detection (UAD) diagnostic assay was developed and validated. The UAD assay can simultaneously detect 13 different serotypes of Streptococcus pneumoniae by capturing serotype-specific S. pneumoniae polysaccharides (PnPSs) secreted in human urine. Assay specificity is achieved by capturing the polysaccharides with serotype-specific monoclonal antibodies (MAbs) on spectrally unique microspheres. Positivity for each serotype was based on positivity cutoff values calculated from a standard curve run on each assay plate together with positive- and negative-control urine samples. The assay is highly specific, since significant signals are detected only when each PnPS was paired with its homologous MAb-coated microspheres. Validation experiments demonstrated excellent accuracy and precision. The UAD assay and corresponding positivity cutoff values were clinically validated by assessing 776 urine specimens obtained from patients with X-ray-confirmed CAP. The UAD assay demonstrated 97% sensitivity and 100% specificity using samples obtained from patients with bacteremic, blood culture-positive CAP. Importantly, the UAD assay identified Streptococcus pneumoniae (13 serotypes) in a proportion of individuals with nonbacteremic CAP, a patient population for which the pneumococcal etiology of CAP was previously difficult to assess. Therefore, the UAD assay provides a specific, noninvasive, sensitive, and reproducible tool to support vaccine efficacy as well as epidemiological evaluation of pneumococcal disease, including CAP, in adults.

Nasal carriage of Streptococcus pneumoniae serotypes and Staphylococcus aureus in Streptococcus pneumoniae-vaccinated and non-vaccinated young children

Since the implementation of Streptococcus pneumoniae (SPn) conjugate vaccination (PCV), non-vaccine types have prevailed in invasive pneumococcal disease (IPD), and an increase in Staphylococcus aureus (SA) burden has been suggested. Here, we assess the epidemiology of SA and SPn nasal carriage in 620 children at day-care centres; 141 of these children had received 1-4 PCV7 doses. A higher vaccine dosage was associated with non-vaccine-type SPn carriage. Of all SPn isolates, 45% were PCV7 types, 1% were additional PCV10 types and 22% were the three additional PCV13 types. SA carriage was inversely associated with vaccine-type SPn carriage. SPn serotype 19A showed higher SA co-carriage rates compared to other SPn serotypes. PCV7 implementation does not prevent children from being part of the IPD-related SPn transmission chain. These results contribute to the monitoring of SA- and SPn-related disease and add to the debate on the current national vaccination policy that recently included a change from PCV7 to PCV10.

Nasopharyngeal colonization elicits antibody responses to staphylococcal and pneumococcal proteins that are not associated with a reduced risk of subsequent carriage

Knowledge of the immunological correlates of Staphylococcus aureus and Streptococcus pneumoniae colonization is required for the search for future protein vaccines. We evaluated natural antibody levels against pneumococcal and staphylococcal proteins in relation to previous bacterial colonization with both pathogens. In a randomized controlled trial, nasopharyngeal samples were obtained from children at 1.5, 6, 12, 18, and 24 months and cultured for S. aureus and S. pneumoniae. Approximately 50% of the children were PCV7 vaccinated. Serum IgG against 18 pneumococcal and 40 staphylococcal proteins was semiquantified by Luminex technology from 111 12 month olds and 158 24 month olds. Previous culture-proven S. aureus colonization was associated with higher IgG levels against 6/40 staphylococcal proteins (ClfB, ClfA, Efb, CHIPS, LukD, and LukF [P ≤ 0.001]) compared to noncarriers. Previous pneumococcal colonization was associated with increased IgG levels against 12/18 pneumococcal proteins compared to noncarriers (P ≤ 0.003). Increasing age was associated with higher levels of antibodies to most pneumococcal proteins and lower levels of antibodies to over half the staphylococcal proteins, reflecting natural colonization dynamics. Anti-S. pneumoniae and anti-S. aureus protein antibodies at the age of 12 months were not negatively correlated with subsequent colonization with the homologous species in the following year and did not differ between PCV7-vaccinated and nonvaccinated children. Colonization with S. aureus and S. pneumoniae induces serum IgG against many proteins, predominantly proteins with immune-modulating functions, irrespective of PCV7 vaccination. None of them appeared to be protective against new acquisition with both pathogens, possibly due to the polymorphic nature of those proteins in the circulating bacterial population.

Lower immunoglobulin G antibody responses to pneumococcal conjugate vaccination at the age of 2 years after previous nasopharyngeal carriage of Streptococcus pneumoniae

OBJECTIVE

To determine whether nasopharyngeal pneumococcal carriage with serotypes 6B, 19F, or 23F interferes with immunoglobulin G (IgG) antibody responses to vaccination with 7-valent pneumococcal conjugate vaccine (PCV7) at the age 24 months.

STUDY DESIGN

Blood samples were collected before and after a PCV7 challenge vaccination at age 24 months from subsets of children participating in a randomized controlled trial. Children previously had received two doses of PCV7 at 2 and 4 months, two plus one doses of PCV7 at 2, 4, and 11 months, or no dosage until 24 months. Nasopharyngeal swabs were cultured at for Streptococcus pneumoniae at age 6 weeks and at 6, 12, 18, and 24 months. IgG responses were determined with enzyme immunoassay.

RESULTS

Lower IgG responses against serotypes 6B, 19F, and 23F were observed on PCV7 challenge vaccination at 24 months in children who had received earlier PCV7 vaccinations and had been found positive for homologous carriage compared with non-carriers of these serotypes. Lower non-homologous IgG responses were observed after the PCV7 challenge at 24 months against serotype 6B after earlier 19F carriage and against serotype 19F after earlier 23F carriage compared with children who had not been positive for carriage of these serotypes.

CONCLUSIONS

Pneumococcal colonization with serotypes 6B, 19F, and 23F is associated with diminished immune responses against these serotypes on PCV7 vaccination at 2 years of age. Underlying mechanisms deserve further investigation.

Cost-effectiveness of 13-valent pneumococcal conjugate vaccine: Germany, Greece, and The Netherlands

BACKGROUND

Seven-valent pneumococcal conjugate vaccine (PCV7) had profound public-health impacts and is considered cost-effective and potentially cost saving. Two new PCVs have been launched, a 10-valent vaccine (PCV10) and a 13-valent vaccine (PCV13). We examined public-health and economic impacts of PCV pediatric national immunization programs (NIPs) in Germany, Greece, and the Netherlands.

METHODS

A decision-analytic model was developed to estimate the impact of PCV13, PCV7, and 10-valent pneumococcal conjugate vaccine (PCV10) on invasive pneumococcal disease (IPD), pneumonia (PNE), and acute otitis media (AOM). Using epidemiological data, we calculated the cases of IPD, PNE, and AOM, using country-specific incidence, serotype coverage, disease sequelae, mortality, vaccine effectiveness, indirect effects, costs, and utilities. Direct effects for PCV13- and PCV10-covered serotypes were assumed similar to PCV7. PCV13 was assumed to confer an indirect effect, while PCV10 was not. Assumptions were tested in sensitivity analyses.

RESULTS

In a NIP, PCV13 was estimated to eliminate 31.7%, 46.4%, and 33.8% of IPD in Germany, Greece, and the Netherlands, respectively. Compared with PCV7 and PCV10, PCV13 was found to be cost-effective or cost saving in all cases when PCV13 indirect effects were included.

CONCLUSIONS

Pediatric NIPs with PCV13 in Europe are expected to have dramatic public-health impacts and be cost-effective or cost saving.