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

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.

Impact of 7-valent versus 10-valent pneumococcal conjugate vaccines on primary care consultations across various age groups in the Netherlands, 5 years after the switch: A time-series analysis

BACKGROUND

In 2011, 10-valent pneumococcal conjugate vaccine (PCV10) replaced PCV7 in The Netherlands. We aimed to assess the impact of this switch on non-invasive pneumococcal disease in primary care across various age-groups, including pneumonia-bronchitis, otitis media (OM) and sinusitis with and without considering pre-PCV10 secular trends.

METHODS

Electronic records of 397,441 individuals included in a regional primary care database from July 2006 to June 2016 were extracted (2,408,762 person-years). We fitted interrupted time-series on annual incidence rates (IR) of primary care diagnosed pneumonia-bronchitis, OM and sinusitis episodes per age-group. We performed these two types of analyses, comparing; 1) the post-PCV10 observed versus expected trend if PCV10 had not been implemented and pre-PCV10 secular trends had continued 2), the pre- versus post-PCV10 observed, model fitted trend. The latter assumes no secular trend. Incidence rate ratios (IRR) were calculated using both methods.

RESULTS

We found significant reductions following PCV10 introduction with both analysis methods for pneumonia-bronchitis in the pediatric and adult age-groups, for sinusitis in the age-group 20-50 years and for OM, the effect across various age-groups are uncertain given contradictory results. For other outcomes and age-groups, the effect estimates were not consistent across the two-method used and heavily depended on the strength of the underlying trend. No consistent effects were observed in the elderly population, considering the two methods used.

CONCLUSION

Our study supports some direct and indirect-effect of PCV10 introduction on non-IPD, mainly on pneumonia-bronchitis, but estimates heavily depend on the method of analysis used. Estimates from the two different approaches may differ substantially if underlying trends are strong.

The Risk of Invasive Pneumococcal Disease Differs between Risk Groups in Norway Following Widespread Use of the 13-Valent Pneumococcal Vaccine in Children

The elderly and adults with medical risk conditions remain at high risk of invasive pneumococcal disease (IPD), highlighting the importance of adequate preventive efforts. In an observational population-based study in Norway (pop ≥ 5 years, 2009-2017) covering six years post-PCV13 implementation, we explored the incidence and risk of IPD associated with age and comorbidities. We obtained the data on 5535 IPD cases from the Norwegian Surveillance System for Communicable Diseases and the population data from Statistics Norway. To define comorbidities, we obtained ICD-10 codes from the Norwegian Patient Registry for the cases and the Norwegian population. The average annual decrease in PCV13 IPD incidence was significant in all risk groups and decreased post-PCV13 introduction by 16-20% per risk group, implying a nondifferential indirect protection from the childhood vaccination. The IPD incidence remained high in the medical risk groups. The relative importance of medical risk conditions was 2.8 to 6 times higher in those aged 5-64 versus ≥65 years for all types of IPD, since age itself is a risk factor for IPD. In groups without medical risk, the risk of IPD was eight times higher in those aged ≥65 compared to those 5-64 years (RR 8.3 (95% CI 7.3-9.5)). Our results underscore the need for age- and risk-group-based prevention strategies.

Serotype Patterns of Pneumococcal Disease in Adults Are Correlated With Carriage Patterns in Older Children

BACKGROUND

The importance of specific serotypes causing invasive pneumococcal disease (IPD) differs by age. Data on pneumococcal carriage in different age groups, along with data on serotype-specific invasiveness, could help explain these age-related patterns and their implications for vaccination.

METHODS

Using pneumococcal carriage and disease data from Israel, we evaluated the association between serotype-specific IPD in adults and serotype-specific carriage prevalence among children in different age categories, while adjusting for serotype-specific invasiveness. We estimated carriage prevalence using different age groupings that were selected a priori. The Deviance Information Criterion was used to determine which age groupings of carriage data best fit the adult IPD data. Serotype-specific disease patterns were further evaluated by stratifying IPD data by comorbidity status.

RESULTS

The relative frequency of serotypes causing IPD differed between adults and children, and also differed between older and younger adults and between adults with and without comorbidities. Serotypes overrepresented as causes of IPD in adults were more commonly carried in older children compared with younger children. In line with this, the serotype-specific frequency of carriage in older children, rather than infants, best correlated with serotype-specific IPD in adults.

CONCLUSIONS

These analyses demonstrate that the serotype patterns in carriage in older children, rather than infants, are best correlated with disease patterns in adults. This might suggest these older children are more influential for disease patterns in adults. These insights could help in optimizing vaccination strategies to reduce disease burden across all ages.

Constrained Optimization for Pneumococcal Vaccination in Brazil

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSION

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

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.

Indirect Effects of Pneumococcal Childhood Vaccination in Individuals Treated With Immunosuppressive Drugs in Ambulatory Care: A Case-cohort Study

BACKGROUND

The extent to which iatrogenically-immunosuppressed individuals benefit from indirect effects of childhood vaccination with pneumococcal conjugate vaccines (PCVs) is unknown. We determined how the sequential introduction of PCV7 (2006) and PCV13 (2011) in the Norwegian childhood vaccination program has affected the epidemiology of invasive pneumococcal disease (IPD) in individuals treated with immunosuppressants in ambulatory care.

METHODS

We conducted a case-cohort study comprising 7926 IPD cases reported to the Norwegian Surveillance System for Communicable Diseases in 2005-2014 and 249998 individuals randomly selected from the National Registry in 2012. We defined immunosuppressive treatment groups based on dispensed prescriptions retrieved from the Norwegian Prescription Database. Incidences and age-adjusted relative risks (RR) were estimated.

RESULTS

IPD incidences decreased in all groups. The PCV13 incidence decreased by 5-12% across groups. The non-PCV13 incidence increased by 4-10%, mostly in individuals on chemotherapy (overlapping 95% confidence intervals). In the PCV13 era, the RR for IPD was highest (significant) and the percentage of cases caused by the polysaccharide vaccine PPV23 serotypes lowest (numerical) in individuals on chemotherapy (RR = 20.4, PPV23 = 52%), followed by individuals on corticosteroids (RR = 6.2, PPV23 = 64%), other immunosuppressants (RR = 5.6, PPV23 = 68%), and no immunosuppressants (RR = 1 [reference], PPV23 = 74%).

CONCLUSIONS

IPD incidences declined after PCV introduction in both immunocompetent and iatrogenically-immunosuppressed individuals, underscoring the benefit of childhood vaccination for the entire population. Still, individuals treated with immunosuppressants in ambulatory care are at increased risk of IPD caused by a more diverse group of serotypes.

Gender differences in community-acquired pneumonia

INTRODUCTION

Community-acquired pneumonia (CAP) is the most common type of lower respiratory tract infection and a major cause of morbidity and mortality in adults worldwide. Sex and gender play an active role in the incidence and outcomes of major infectious diseases, including CAP.

EVIDENCE ACQUISITION

We searched the following electronic databases from January 2001 to December 2018: MEDLINE, EMBASE, CINHAIL, CENTRAL (Cochrane Central register of Controlled Trials), DARE (Database of Abstracts of Reviews of Effectiveness), Cochrane Database of Systematic Reviews and ACP Journal Club database.

EVIDENCE SYNTHESIS

Several studies have reported higher male susceptibility to pulmonary infections and higher risk of death due to sepsis. Biological differences (e.g. hormonal cycles and cellular immune-mediated responses) together with cultural, behavioral and socio-economic differences are important determinants of the course and outcome of CAP. However, gender-related bias in the provision of care and use of hospital resources has been reported among women, resulting in delayed hospital admission and consequently necessary care.

CONCLUSIONS

CAP is more severe in males than in females, leading to higher mortality in males, especially in older age. To identify gender differences in CAP can guide patient's prognostication and management.

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.

Impact of infectious diseases on population health using incidence-based disability-adjusted life years (DALYs): results from the Burden of Communicable Diseases in Europe study, European Union and European Economic Area countries, 2009 to 2013

The Burden of Communicable Diseases in Europe (BCoDE) study aimed to calculate disability-adjusted life years (DALYs) for 31 selected diseases in the European Union (EU) and European Economic Area (EEA). Methods: DALYs were estimated using an incidence-based and pathogen-based approach. Incidence was estimated through assessment of data availability and quality, and a correction was applied for under-estimation. Calculation of DALYs was performed with the BCoDE software toolkit without applying time discounting and age-weighting. Results: We estimated that one in 14 inhabitants experienced an infectious disease episode for a total burden of 1.38 million DALYs (95% uncertainty interval (UI): 1.25–1.5) between 2009 and 2013; 76% of which was related to the acute phase of the infection and its short-term complications. Influenza had the highest burden (30% of the total burden), followed by tuberculosis, human immunodeficiency virus (HIV) infection/AIDS and invasive pneumococcal disease (IPD). Men had the highest burden measured in DALYs (60% of the total), adults 65 years of age and over had 24% and children less than 5 years of age had 11%. Age group-specific burden showed that infants (less than 1 year of age) and elderly people (80 years of age and over) experienced the highest burden. Conclusions: These results provide baseline estimates for evaluating infectious disease prevention and control strategies. The study promotes an evidence-based approach to describing population health and assessing surveillance data availability and quality, and provides information for the planning and prioritisation of limited resources in infectious disease prevention and control.

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

INTRODUCTION

In 2006, the Netherlands introduced the 7-valent pneumococcal conjugate vaccine (PCV7) in their national immunisation programme. In 2011, PCV7 was replaced by the 10-valent vaccine (PCV10). We report on the impact of PCV on invasive pneumococcal disease (IPD) incidence, clinical syndromes and patient outcomes.

METHODS

Pneumococcal isolates of hospitalised IPD patients between June 2004 and May 2018 were obtained from nine sentinel laboratories, covering 25% of the Dutch population. All isolates were serotyped. IPD incidence and clinical outcome were determined before and after introduction of PCV7 and after the switch to PCV10, stratified by age and serotype.

RESULTS

Compared to before PCV7 introduction, significant declines in IPD incidence were observed in 2016-2018 in children <5 years (69%), 18-49 year olds (31%) and ≥65 year olds (19%). Compared to before PCV10 introduction, the IPD incidence in 2016-2018 declined in children <5 years (RR:0.68, 95%CI:0.42-1.11), 5-17 year olds (RR:0.58, 95%CI:0.29-1.14) and 18-49 year olds (RR:0.72, 95%CI:0.57-0.90), but not in 50-64 year olds (RR:0.94, 95%CI:0.81-1.10) and ≥65 year olds (RR:1.04, 95%CI:0.0.93-1.15). While the case fatality rate (CFR) decreased from 16.2% pre-PCV to 13.4% post-PCV10 (RR:0.83, 95%CI:0.70-0.99), the switch to PCV10 had no further impact on CFR (RR:1.14, 95%CI:0.96-1.36).

CONCLUSION

Twelve years of PCV in the Netherlands has resulted in a sustained reduction of IPD incidence in children and younger adults. The switch from PCV7 to PCV10 did not have additional impact on the IPD incidence in older adults and CFR due to emerging non-vaccine serotypes.

The impact of childhood pneumococcal vaccination on hospital admissions in England: a whole population observational study

Background

Pneumococcal infections are major causes of morbidity and mortality worldwide. We use routine hospital admissions data and time-series modelling analysis to estimate the impact of the seven and thirteen valent pneumococcal conjugate vaccines (PCV7 and PCV13) on hospital admissions due to pneumococcal disease in England.

Methods

Hospital admissions for pneumococcal meningitis, bacteraemia and pneumonia between January 1, 2003 and December 31, 2015 were identified from the national Hospital Episode Statistics database for all age groups in England. We model the impact of pneumococcal vaccination using interrupted time series analysis. Hospital admissions prior to vaccine introduction were extrapolated to predict the expected number of admissions in the absence of pneumococcal vaccines. Admissions avoided over time were estimated by comparing the fitted interrupted time series and the expected model for no vaccination in a Bayesian framework.

Results

Overall, there were 43,531 (95% credible interval (CrI): 36486–51,346) fewer hospital admissions due to bacteraemia, meningitis and pneumonia in England during the period from 2006 to 2015 than would have been expected if pneumococcal vaccines had not been implemented, with the majority of hospital admissions avoided due to pneumonia. Among young children reductions in meningitis were more common, while among adults reductions in pneumonia admissions were relatively more important, with no evidence for reduced bacteraemia and meningitis among older adults. We estimated that 981 (95% CrI: 391–2018), 749 (95% CrI: 295–1442) and 1464 (95% CrI: 793–2522) bacteraemia, meningitis and pneumonia related hospital admissions, respectively, were averted in children < 2 years of age.

Conclusions

Substantial reductions in hospital admissions for bacteraemia, meningitis and pneumonia in England were estimated after the introduction of childhood vaccination, with indirect effects being responsible for most of the hospital admissions avoided.

Electronic supplementary material

The online version of this article (10.1186/s12879-019-4119-8) contains supplementary material, which is available to authorized users.

Serotype-Specific IgG Antibody Waning after Pneumococcal Conjugate Primary Series Vaccinations with either the 10-Valent or the 13-Valent Vaccine

The two currently available ten- and thirteen-valent pneumococcal conjugate vaccines (PCV10 and PCV13) both induce serotype-specific IgG anti-polysaccharide antibodies and are effective in preventing vaccine serotype induced invasive pneumococcal disease (IPD) as well as in reducing overall vaccine-serotype carriage and transmission and thereby inducing herd protection in the whole population. IgG levels decline after vaccination and could become too low to prevent carriage acquisition and/or pneumococcal disease. We compared the levels of 10-valent (PCV10) and 13-valent (PCV13) pneumococcal vaccine induced serum IgG antibodies at multiple time points after primary vaccinations. Data from two separate studies both performed in the Netherlands in infants vaccinated at 2, 3, and 4 months of age with either PCV10 or PCV13 were compared. Antibody levels were measured at 5, 8, and 11 months of age, during the interval between the primary immunization series and the 11-months booster dose. Serotype-specific IgG levels were determined by multiplex immunoassay. Although antibody kinetics showed significant variation between serotypes and between vaccines for the majority of the 10 shared serotypes, i.e., 1, 5, 7F, 9V, 14, 18C, and 23F, antibody concentrations were sufficiently high for both vaccines, immediately after the primary series and throughout the whole period until the booster dose. In contrast, for serotypes 4 and 19F in the PCV10 group and for serotypes 4 and 6B in the PCV13 group, IgG antibody concentrations already come within reach of the frequently used seroprotection level of 0.35 μg/mL immediately after the primary series at the five month time point and/or at eight months. This paper addresses the importance of revealing differences in serotype-specific and pneumococcal vaccine-dependent IgG antibody patterns during the interval between the primary series and the booster dose, an age period with a high IPD incidence. Trial registration: www.trialregister.nl NTR3069 and NTR2316.

Triptych of the Hermit Saints: pneumococcal polysaccharide vaccines for the elderly

Pneumococcal pneumonia is a serious disease with considerable morbidity and mortality in the elderly. Despite adequate antibiotic treatment, the long-term mortality of pneumococcal pneumonia remains high. Preventive measures in the form of vaccination, therefore, are warranted. Twenty-three-valent polysaccharide vaccines have a broad coverage but limited efficacy. Pneumococcal conjugate vaccines have been shown in children to be able to prevent invasive and mucosal pneumococcal diseases. It should be realized that the serotype composition of current pneumococcal conjugate vaccines is not tailored for the elderly, and that replacement disease can occur. Yet, the current 13-valent conjugate vaccine has been shown to protect against infections with vaccine serotypes. Long-term mortality of pneumococcal pneumonia should be included in policy making about the introduction of these vaccines for the elderly.

Increased carriage of non-vaccine serotypes with low invasive disease potential four years after switching to the 10-valent pneumococcal conjugate vaccine in The Netherlands

The 7-valent pneumococcal conjugate vaccine (PCV7) was introduced in The Netherlands in 2006 and was replaced by PHiD-CV10 in 2011. Data on carriage prevalence of S. pneumoniae serotypes in children and invasive pneumococcal disease (IPD) in children and older adults were collected to examine the impact of PCVs on carriage and IPD in The Netherlands. Pneumococcal carriage prevalence was determined by conventional culture of nasopharyngeal swabs in 24-month-old children in 2015/2016. Data were compared to similar carriage studies in 2005 (pre-PCV7 introduction), 2009, 2010/2011 and 2012/2013. Invasive pneumococcal disease isolates from hospitalized children <5 years and adults >65 years (2004–2016) were obtained by sentinel surveillance. All isolates were serotyped by Quellung. Serotype invasive disease potential was calculated using carriage and nationwide IPD data in children. The overall pneumococcal carriage rate was 48% in 2015/2016, lower than in 2010/2011 (64%) and pre-vaccination in 2005 (66%). Carriage of the previously dominant non-vaccine serotypes 19A and 11A has declined since 2010/2011, from 14.2% to 4.6% and 4.2% to 2.7%, respectively, whereas carriage of serotypes 6C and 23B has increased (4.2% to 6.7% and 3.9% to 7.3%), making serotypes 6C and 23B the most prevalent carriage serotypes. IPD incidence declined in children (20/100,000 cases in 2004/2006 to 6/100,000 cases in 2015/2016) as well as in older adults (63/100,000 cases to 51/100,000 cases). Serotypes 6C, 23B and 11A have high carriage prevalence in children, but show low invasive disease potential. Serotype 8 is the main causative agent for IPD in older adults (11.3%). In conclusion, 10 years after the introduction of pneumococcal vaccination in children in The Netherlands shifts in carriage and disease serotypes are still ongoing. Surveillance of both carriage and IPD is important to assess PCV impact and to predict necessary future vaccination strategies in both children and older adults.

Towards the introduction of pneumococcal conjugate vaccines in Bhutan: A cost-utility analysis to determine the optimal policy option

BACKGROUND

Due to competing health priorities and limited resources, many low-income countries, even those with a high disease burden, are not able to introduce pneumococcal conjugate vaccines.

OBJECTIVE

To determine the cost-utility of 10- and 13-valent pneumococcal conjugate vaccines (PCV10 and PCV13) compared to no vaccination in Bhutan.

METHODS

A model-based cost-utility analysis was performed in the Bhutanese context using a government perspective. A Markov simulation model with one-year cycle length was used to estimate the costs and outcomes of three options: PCV10, PCV13 and no PCV programmes for a lifetime horizon. A discount rate of 3% per annum was applied. Results are presented using an incremental cost-effectiveness ratio (ICER) in United State Dollar per quality-adjusted life year (QALY) gained (USD 1 = Ngultrum 65). A one-way sensitivity analysis and a probabilistic sensitivity analysis were conducted to assess uncertainty.

RESULTS

Compared to no vaccination, PCV10 and PCV13 gained 0.0006 and 0.0007 QALYs with additional lifetime costs of USD 0.02 and USD 0.03 per person, respectively. PCV10 and PCV13 generated ICERs of USD 36 and USD 40 per QALY gained compared to no vaccination. In addition, PCV13 produced an ICER of USD 92 compared with PCV10. When including PCV into the Expanded Programme on Immunization, the total 5-year budgetary requirement is anticipated to increase to USD. 3.77 million for PCV10 and USD 3.75 million for PCV13. Moreover, the full-time equivalent (FTE) of one health assistant would increase by 2.0 per year while the FTE of other health workers can be reduced each year, particularly of specialist (0.6-1.1 FTE) and nurse (1-1.6 FTE).

CONCLUSION

At the suggested threshold of 1xGDP per capita equivalent to USD 2708, both PCVs are cost-effective in Bhutan and we recommend that they be included in the routine immunization programme.

Changes in Childhood Pneumonia Hospitalizations by Race and Sex Associated with Pneumococcal Conjugate Vaccines

Introduction of pneumococcal conjugate vaccines in the childhood immunization schedule was associated with decreases in all-cause pneumonia hospitalizations among black and white children in Tennessee, USA. Although racial disparities that existed before introduction of these vaccines have been substantially reduced, rates remain higher in boys than in girls among young children.

Changes in pathogens and pneumococcal serotypes causing community-acquired pneumonia in The Netherlands

BACKGROUND

In 2006 a 7-valent pneumococcal conjugate vaccine (PCV7) was introduced in the immunisation programme for infants in The Netherlands and replaced by PCV10 in 2011. Limited data exist about the impact of PCV on the aetiology of CAP as a whole. The aim of the present study is to describe the overall changes in microbial aetiology, pneumococcal burden (including non-bacteraemic pneumococcal pneumonia) and its serotypes in adult community-acquired pneumonia (CAP) after the introduction of these PCVs.

METHODS

Hospitalised adult CAP patients who participated in three consecutive trials were studied (2004-2006 (n=201), 2007-2009 (n=304) and 2012-2016 (n=300) and considered as pre-PCV7, PCV7 and PCV10 period). Extensive conventional microbiological testing was applied for all patients. In addition, patients with a serotype-specific pneumococcal antibody response were diagnosed with pneumococcal CAP. Changes in proportions of causative pathogens and distributions of pneumococcal serotypes were calculated.

RESULTS

The proportion of pneumococcal CAP decreased from 37% (n=74/201) to 26% (n=77/300) comparing the pre-PCV7 period with the PCV10 period (p=0.01). For other pathogens, including Legionella spp., Mycoplasma pneumoniae, S. aureus, H. influenzae, and respiratory viruses, no sustained shifts were observed in their relative contribution to the aetiology of CAP. Within the pneumococcal CAP patients, we observed a decrease in PCV7 and an increase in non-PCV10 serotype disease. PCV10-extra type disease did not decrease significantly comparing the PCV10 period with the pre-PCV7 and PCV7 period, respectively. Notably, PCV7 type disease decreased both in bacteraemic and non-bacteraemic patients.

CONCLUSIONS

Our findings confirm that PCV introduction in infants impact the microbial aetiology of adult CAP and suggest herd effects in adults with CAP after introduction of PCVs in children.

Streptococcus pneumoniae antimicrobial resistance decreased in the Helsinki Metropolitan Area after routine 10-valent pneumococcal conjugate vaccination of infants in Finland

Since the introduction of 10-valent pneumococcal conjugate vaccine (PCV10) into the Finnish national vaccination program in September 2010, the incidence of invasive pneumococcal disease in children has decreased steeply in Finland. We studied the antimicrobial susceptibility of invasive and non-invasive Streptococcus pneumoniae (pneumococcus) isolated in the Helsinki Metropolitan Area during 2009-2014. We divided the data into two age groups: isolates from patients <5 years old and ≥5 years old. We also studied the serotype distribution of invasive isolates and of a subset of non-invasive multidrug-resistant isolates. The invasive isolate numbers recovered from patients aged <5 years old declined from 33/228 (15%) in 2009 to 8/208 (4%) in 2014 (p < 0.001) and non-invasive isolate numbers declined during the same time period from 221/595 (37%) to 119/432 (28%) (p < 0.001). At the same time, the proportion of penicillin non-susceptible non-invasive isolates in this age group decreased from 25% (56/220) to 13% (15/119) (p = 0.001) and multidrug-resistant isolates from 22% (49/220) to 6% (7/119) (p < 0.001), respectively. The number of PCV10 serotype isolates also decreased among the serotyped multidrug-resistant non-invasive isolates. Among patients aged ≥5 years old, the isolate numbers did not show a similar decreasing trend compared to the younger group and, further, the number of non-PCV10 serotype isolates increased in invasive cases. To conclude, the antimicrobial non-susceptibility of pneumococcus has decreased markedly, especially among young patients (<5 years old), following PCV10 implementation in Finland.

Sex differences in invasive pneumococcal disease and the impact of pneumococcal conjugate vaccination in the Netherlands, 2004 to 2015

Implementation of pneumococcal conjugate vaccines in the Netherlands (PCV7 in 2006 and PCV10 in 2011) for infants caused a shift in serotypes in invasive pneumococcal disease (IPD). We explored sex differences in serotype-specific IPD incidence before and after vaccine introduction. Incidences in the pre-PCV7 (June 2004–May 2006), post-PCV7 (June 2008–May 2011) and post-PCV10 period (June 2013–May 2015), stratified by age, were compared. Incidence was higher in men for all age groups (overall in men: 16.7, 15.5 and 14.4/100,000 and women: 15.4, 13.6 and 13.9/100,000 pre-PCV7, post-PCV7 and post-PCV10, respectively), except for 20–39 year-olds after PCV7 and 40–64 year-olds after PCV10 introduction. After PCV7 and PCV10 introduction, the overall IPD incidence decreased in men aged 20–39 years (from 5.3 pre-PCV7 to 4.7 and 2.6/100,000 post-PCV7 and post-PCV10, respectively), whereas it showed a temporary increase in women (from 3.9/100,000 pre-PCV7 to 5.0/100,000 post-PCV7 and back to 4.0/100,000 post-PCV10) due to replacement disease. PCV10 herd effects were observed throughout, but in women older than 40 years, a significant increase in non-PCV10 serotype offset a decrease in overall IPD incidence. Ongoing surveillance of IPD incidence by sex is important to evaluate the long-term effects of PCV implementation.

Long-term mortality after IPD and bacteremic versus non-bacteremic pneumococcal pneumonia

BACKGROUND

Short-term mortality after invasive pneumococcal disease (IPD) and pneumococcal pneumonia is high but data on long-term mortality (including the comparison between bacteremic and non-invasive/non-bacteremic pneumococcal pneumonia) within the first years after diagnosis are scarce.

METHODS

Adult patients with 'non-pneumonia' IPD and 'invasive pneumonia' (from 2004 to 2012) and with 'bacteremic' vs 'non-invasive/non-bacteremic (NI/NB)' pneumococcal pneumonia (from 2008 to 2012) diagnosed by negative blood culture but a positive urinary antigen test (UAT) were identified in a Dutch hospital. Mortality of patients up to 10years after diagnosis was compared with age- and sex-matched life-expectancy data of the general population. Multivariable Cox regression analysis was used to study predictors for mortality in invasive pneumonia patients and to adjust for confounders comparing mortality between bacteremic and NI/NB/UAT-positive pneumonia patients.

RESULTS

Of 228 invasive pneumonia patients 17% died within 30days and in 30-day survivors cumulative long-term mortality at 1 and 5years were 16% and 39% as compared with 3% and 15% in age- and sex-matched persons. High mortality was largely dependent on pre-existent comorbidities. In invasive pneumonia patients who survived the first 30days, age, male gender, chronic cardiovascular disease, malignancy and PCV7 serotype disease were independent predictors for higher long-term mortality. For bacteremic pneumonia patients (n=128) 30-day mortality was 16% and almost similar to 14% in NI/NB/UAT-positive pneumococcal pneumonia patients (n=170). In 30-day survivors of bacteremic pneumonia (n=108, median age 66years), cumulative mortality at 1 and 3years were 13% and 29% as compared with 18% and 40% in NI/NB/UAT-positive pneumococcal pneumonia patients (n=146, median age 67years) without a significant difference in mortality.

CONCLUSIONS

Approximately 40% of all patients, who survived the first 30days after presentation with non-pneumonia IPD and pneumococcal pneumonia died within the following 5years. High long-term mortality was largely dependent on pre-existent comorbidity.

Temporal cross-correlation between influenza-like illnesses and invasive pneumococcal disease in The Netherlands

Background

While the burden of community‐acquired pneumonia and invasive pneumococcal disease (IPD) is still considerable, there is little insight in the factors contributing to disease. Previous research on the lagged relationship between respiratory viruses and pneumococcal disease incidence is inconclusive, and studies correcting for temporal autocorrelation are lacking.

Objectives

To investigate the temporal relation between influenza‐like illnesses (ILI) and IPD, correcting for temporal autocorrelation.

Methods

Weekly counts of ILI were obtained from the Sentinel Practices of NIVEL Primary Care Database. IPD data were collected from the Dutch laboratory‐based surveillance system for bacterial meningitis from 2004 to 2014. We analysed the correlation between time series, pre‐whitening the dependent time series with the best‐fit seasonal autoregressive integrated moving average (SARIMA) model to the independent time series. We performed cross‐correlations between ILI and IPD incidences, and the (pre‐whitened) residuals, in the overall population and in the elderly.

Results

We found significant cross‐correlations between ILI and IPD incidences peaking at lags ‐3 overall and at 1 week in the 65+ population. However, after pre‐whitening, no cross‐correlations were apparent in either population group.

Conclusion

Our study suggests that ILI occurrence does not seem to be the major driver of IPD incidence in The Netherlands.

Invasive Pneumococcal Disease 3 Years after Introduction of 10-Valent Pneumococcal Conjugate Vaccine, the Netherlands

Three years after a 7-valent pneumococcal conjugate vaccine was replaced by a 10-valent pneumococcal conjugate vaccine in the Netherlands, we observed a decrease in incidence of invasive pneumococcal disease caused by Streptococcus pneumoniae serotypes 1, 5, and 7F. Our data do not support or exclude cross-protection against serotype 19A.

Trend of invasive pneumococal disease (IPD) in a South Western, Nigerian hospital

The recent introduction of the Heptavalent-pneumococcal vaccine (PCV-7) by private pharmaceutical companies in Nigeria, has generated interest in invasive bacterial diseases particularly IPD. Our objective in this study is to investigate the trend and occurrence rate of IPD in Abeokuta, Nigeria. Suspected IPD cases were assessed from Jan 2010 to Dec 2010 for demographic and Microbiological characteristics. Bacterial isolations and antibiotics susceptibility testing followed standard bacteriological procedure. Overall 471 cases of probable IPD was assessed, with 21(4.5%) cases of suspected pneumonia, 109(23.1%) cases of suspected meningitis, and 341(72.4%) cases of suspected septicaemia. Confirmed IPD cases were 9 with 2 cases of meningitis, 3 cases of septicaemia and 4 cases of pneumonia. Age range distribution showed, high distribution of IPD cases among children >1 with 5(55.6%) there was a statistically significant difference in gender p< 0.05 (X2 test) with females recording a higher occurrence than males. We conclude by advocating for better detection methods against IPD meningitis cases, and continuous surveillance into the serotypes of streptococcus pneumonia as well inclusion of the PCV vaccine into our childhood immunization program.

Active hospital-based surveillance of invasive pneumococcal disease and clinical pneumonia in infants and young children in two Polish counties

INTRODUCTION

Invasive pneumococcal disease (IPD) incidence, serotype distribution, and antibiotic susceptibility of Streptococcus pneumoniae were estimated in children aged 28 days to < 60 months.

MATERIAL AND METHODS

One-year prospective, hospital-based surveillance was conducted starting on February 15, 2008, at two children's hospitals serving the city and surrounding county of Poznań and Poznański, Poland. Eligible children had fever ≥ 39.0°C or physician-suspected IPD. Blood cultures were obtained from all children, cerebrospinal fluid in suspected meningitis cases, and chest radiographs (CXRs) in suspected pneumonia cases.

RESULTS

Seven of 1,581 eligible children had confirmed IPD. Estimated IPD incidence per 100,000 children was 11.89 (95% CI: 4.78-24.50) overall and 20.1 (95% CI: 6.52-46.84) in subjects aged 28 days to < 24 months. One S. pneumoniae isolate of each of the following serotypes was obtained: 6B, 14, 23A, 23F, and 33F. Two isolates were resistant to both trimethoprim-sulfamethoxazole and erythromycin. Clinical pneumonia incidence among children aged 28 days to < 24 months and 24 months to < 60 months was 3,151.3 (95% CI: 2934.7-3379.7) and 962.7 (95% CI: 861.2-10,072.9) per 100,000 children, respectively. CXR-confirmed pneumonia rates in the same groups were 1,035.7 (95% CI: 913.2-1,170.1) and 379.8 (95% CI: 317.1-451.3) per 100,000 children, respectively.

CONCLUSIONS

IPD is an important cause of morbidity in Poznań and Poznański county, Poland. Among participants aged < 5 years with fever or suspected IPD, pneumonia was the most common diagnosis and was highest in children aged < 24 months.

A systematic review of the burden of vaccine preventable pneumococcal disease in UK adults

Background

Invasive pneumococcal disease (IPD) and pneumococcal pneumonia are common and carry a significant morbidity and mortality. Current strategies to prevent pneumococcal disease are under review in the United Kingdom (UK). We conducted a systematic review to evaluate the burden of vaccine type adult pneumococcal disease specifically in the UK.

Methods

A systematic review conducted and reported according to MOOSE guidelines. Relevant studies from 1990 to 2015 were included. The primary outcome was the incidence of vaccine type pneumococcal disease, focussing on the pneumococcal polysaccharide vaccine (PPSV), the 13-valent conjugate vaccine (PCV13) and the 7-valent conjugate vaccine (PCV7).

Results

Data from surveillance in England and Wales from 2013/14 shows an incidence of 6.85 per 100,000 population across all adult age groups for IPD, and an incidence of 20.58 per 100,000 population in those aged >65 years. The corresponding incidences for PCV13 serotype IPD were 1.4 per 100,000 and 3.72 per 100,000. The most recent available data for community-acquired pneumonia (CAP) including non-invasive disease showed an incidence of 20.6 per 100,000 for adult pneumococcal CAP and 8.6 per 100,000 population for PCV13 serotype CAP. Both IPD and CAP data sources in the UK suggest an ongoing herd protection effect from childhood PCV13 vaccination causing a reduction in the proportion of cases caused by PCV13 serotypes in adults. Despite this, applying the incidence rates to UK population estimates suggests more than 4000 patients annually will be hospitalised with PCV13 serotype CAP and more than 900 will be affected by IPD, although with a trend for these numbers to decrease over time.

There was limited recent data on serotype distribution in high risk groups such as those with chronic respiratory or cardiac disease and no data available for vaccine type (VT) CAP managed in the community where there is likely to be a considerable unmeasured burden.

Conclusion

The most recent available data suggests that VT pneumococcal disease continues to have a high burden in UK adults despite the impact of childhood PCV13 vaccination. IPD estimates represent only a fraction of the total burden of pneumococcal disease.

Study registration

PROSPERO CRD42015025043

Electronic supplementary material

The online version of this article (doi:10.1186/s12890-016-0242-0) contains supplementary material, which is available to authorized users.

Serotype Distribution and Antimicrobial Susceptibilities of Invasive Streptococcus pneumoniae Isolates from Adults in Korea from 1997 to 2012

In Republic of Korea, a 7-valent pneumococcal conjugated vaccine (PCV7) was licensed for use in infants in 2003, and 13-valent PCV (PCV13) replaced it since 2010. We investigated trends in serotype distribution and antibiotic susceptibility of pneumococcal isolates from adult patients with invasive pneumococcal diseases (IPD). Invasive pneumococcal isolates from adult patients of ≥ 16 years of age were collected from 1997 to 2012. Serotypes of the isolates were determined by the Quellung reaction. Distribution of serotypes was analyzed according to the vaccine types. Antibiotic susceptibility was tested by using E-test strips. A total of 272 invasive pneumococcal isolates were included. The most common serotypes were serotype 19F (8.5%, 23/272), and serotype 3 (8.1%, 22/272), and 24.6% (67/272) of the isolates were of non-vaccine serotypes. Of the 272 isolates, 2.6% (7/272) were penicillin MICs of ≥ 4 µg/mL. The proportion of the PCV13 serotypes decreased from 63.3% (50/79) in 1997-2003 to 48.6% (17/35) in 2011-2012, whereas that of non-vaccine serotypes was 26.6% (21/79) and 25.7% (9/35), respectively, for the same periods. The proportion of the PCV13 serotypes showed a decreasing trend among adult patients with IPD over the study period.

Influence of Childhood Pneumococcal Conjugate Vaccines on Invasive Pneumococcal Disease in Adults With Underlying Comorbidities in Calgary, Alberta (2000-2013)

BACKGROUND

Pneumococcal conjugate vaccine (PCV) was introduced into Alberta, Canada's routine childhood immunization programs in 2002 (7-valent [PCV7]) and 2010 (13-valent [PCV13]). We assessed the effect of these programs on the epidemiology of invasive pneumococcal disease (IPD) to determine if PCV-associated indirect protection was relatively reduced in adults with underlying comorbidities.

METHODS

Demographic and clinical data were collected by a prospective, population-based surveillance system in Calgary, Alberta, Canada, from January 2000 to December 2013. An indirect cohort study design was used to assess for changes in the proportion of IPD cases with underlying comorbidities.

RESULTS

There were 1598 overall and 1346 adult IPD cases from 1 January 2000 to 31 December 2013. Overall IPD incidence decreased 33% (age 0-5 months), 86% (6-23 months), 67% (2-4 years), 26% (5-17 years), 22% (18-64 years), 36% (65-84 years), and 42% (≥85 years) from the prevaccine (January 2000-July 2002) to the post-PCV13 (July 2010-December 2013) period. Over the same timeframe, PCV7 serotype disease incidence declined to ≤1 case per 100 000 persons in all age groups. Neither the proportion of adult cases with immunocompetent comorbidities (relative risk ratio [RRR], 0.93; 95% confidence interval [CI], .62-1.40) nor immunocompromising comorbidities (RRR, 0.99; 95% CI, .61-1.61) differed between the pre-PCV period and post-PCV era.

CONCLUSIONS

Childhood PCV programs have provided considerable benefit, with substantial declines in overall and vaccine-serotype IPD in vaccinated children and in unvaccinated persons. Conjugate vaccine-associated indirect protection for adults with comorbidities was similar to that for healthy adults.

Disease Burden of 32 Infectious Diseases in the Netherlands, 2007-2011

BACKGROUND

Infectious disease burden estimates provided by a composite health measure give a balanced view of the true impact of a disease on a population, allowing the relative impact of diseases that differ in severity and mortality to be monitored over time. This article presents the first national disease burden estimates for a comprehensive set of 32 infectious diseases in the Netherlands.

METHODS AND FINDINGS

The average annual disease burden was computed for the period 2007-2011 for selected infectious diseases in the Netherlands using the disability-adjusted life years (DALY) measure. The pathogen- and incidence-based approach was adopted to quantify the burden due to both morbidity and premature mortality associated with all short and long-term consequences of infection. Natural history models, disease progression probabilities, disability weights, and other parameters were adapted from previous research. Annual incidence was obtained from statutory notification and other surveillance systems, which was corrected for under-ascertainment and under-reporting. The highest average annual disease burden was estimated for invasive pneumococcal disease (9444 DALYs/year; 95% uncertainty interval [UI]: 8911-9961) and influenza (8670 DALYs/year; 95% UI: 8468-8874), which represents 16% and 15% of the total burden of all 32 diseases, respectively. The remaining 30 diseases ranked by number of DALYs/year from high to low were: HIV infection, legionellosis, toxoplasmosis, chlamydia, campylobacteriosis, pertussis, tuberculosis, hepatitis C infection, Q fever, norovirus infection, salmonellosis, gonorrhoea, invasive meningococcal disease, hepatitis B infection, invasive Haemophilus influenzae infection, shigellosis, listeriosis, giardiasis, hepatitis A infection, infection with STEC O157, measles, cryptosporidiosis, syphilis, rabies, variant Creutzfeldt-Jakob disease, tetanus, mumps, rubella, diphtheria, and poliomyelitis. The very low burden for the latter five diseases can be attributed to the National Immunisation Programme. The average disease burden per individual varied from 0.2 (95% UI: 0.1-0.4) DALYs per 100 infections for giardiasis, to 5081 and 3581 (95% UI: 3540-3611) DALYs per 100 infections for rabies and variant Creutzfeldt-Jakob disease, respectively.

CONCLUSIONS

For guiding and supporting public health policy decisions regarding the prioritisation of interventions and preventive measures, estimates of disease burden and the comparison of burden between diseases can be informative. Although the collection of disease-specific parameters and estimation of incidence is a process subject to continuous improvement, the current study established a baseline for assessing the impact of future public health initiatives.

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.

Etiology of Pneumonia in a Pediatric Population with High Pneumococcal Vaccine Coverage: A Prospective Study

BACKGROUND

Improved Childhood Immunizations Programs, especially the introduction of pneumococcal vaccination, better diagnostic methods and the importance of reduced antibiotic misuse, make this a critical time to increase knowledge on the etiology of pediatric pneumonia. Our main objective was to identify the contribution of various microbiological species that causes pneumonia in previously healthy children and adolescents in a population with high pneumococcal conjugate vaccine coverage.

METHODS

This prospective, observational study enrolled patients with clinical and radiological signs of pneumonia over a 2-year period. Both inpatients and outpatients were included. Paired sera, nasopharyngeal polymerase chain reaction and bacterial cultures from blood and pleura were analyzed to detect potential viral and bacterial causative pathogens.

RESULTS

TWO HUNDRED AND SIXTY-FIVE: cases of clinical and radiological verified pneumonia were identified. The pneumococcal vaccine coverage was 85%. We identified a causative pathogen in 84.2% of all cases; 63.4% with single viral etiology, 11.3% with pneumococcus and 7.5% with mycoplasma infection. Respiratory syncytial virus was the most common pathogen in children younger than 5 years, whereas mycoplasma was the most common in older children.

CONCLUSIONS

We identified the majority of 265 cases with radiology proven pneumonia as single viral infections, predominantly respiratory syncytial virus and a much lower proportion of bacterial causes. These findings may impact pneumonia management guidelines in areas where widespread pneumococcal vaccination is provided and contribute to reduced antibiotic overuse in pediatric pneumonia.

Dynamics and Determinants of Pneumococcal Antibodies Specific against 13 Vaccine Serotypes in the Pre-Vaccination Era

Introduction

Introduction of pneumococcal conjugate vaccines (PCVs) for infants decreased overall invasive pneumococcal disease (IPD), while non-vaccine serotype IPD increased. To fully understand this serotype replacement, knowledge about serotype dynamics in the pre-vaccine era is needed. In addition to IPD surveillance and carriage studies, the serotype replacement can be investigated by serosurveillance studies. The current study compared the results of two Dutch serosurveillance studies conducted in 1995–1996 (PIENTER1) and 2006–2007 (PIENTER2).

Methods

Participants in these studies donated a blood sample and completed a questionnaire. Pneumococcal antibodies of serotypes included in PCV13 were measured with a fluorescent-bead based multiplex immunoassay. Geometric mean antibody concentrations (GMCs) and determinants of pneumococcal antibody levels were investigated.

Results

GMCs were higher in PIENTER2 for serotypes 1, 6A, 6B, 9V, 18C, 19F and 23F and lower for 3 and 5. Age, day care attendance, household size, vaccination coverage, and urbanisation rate were associated with pneumococcal antibodies in children. Education level, ethnicity, age, low vaccination coverage sample, urbanisation rate, and asthma/COPD were associated with pneumococcal antibodies in elderly. The determinants significantly associated with pneumococcal IgG were slightly different for the elderly in PIENTER1 compared to the elderly in PIENTER2.

Conclusion

Although most of the serotype antibody levels remained stable, some of the serotype-specific antibody levels varied during the pre-vaccine era, indicating that exposure of certain serotypes changes without interference of PCVs.

Invasive pneumococcal disease: Clinical outcomes and patient characteristics 2-6 years after introduction of 7-valent pneumococcal conjugate vaccine compared to the pre-vaccine period, the Netherlands

BACKGROUND

Implementation of 7-valent pneumococcal conjugate vaccine (PCV7) in the Dutch national immunization program for infants led to a shift from vaccine to non-vaccine serotypes in invasive pneumococcal disease (IPD) in all age groups. We studied the impact of the serotype shift on clinical syndromes and outcomes.

METHODS

Pneumococcal isolates from hospitalized IPD patients obtained from nine sentinel microbiology laboratories, covering 25% of the Dutch population, were serotyped. Clinical syndromes, outcomes and patient characteristics in the post-PCV7 (2008-2012) period were compared with the pre-PCV7 period (2004-2006). Serotype specific propensity of the association with empyema, meningitis and death was calculated.

RESULTS

Invasive pneumonia incidence significantly decreased in children <5 years and elderly ≥65 years, but increased in 5-64 years old from 4.92 to 5.58 cases/100.000/year (RR 1.13 95% CI 0.99-1.29). Empyema incidence significantly increased in elderly 65 years and older from 0.61 to 2.60 cases/100.000/year (RR 4.28 95% CI 1.97-9.33), mainly due to serotype 1. The incidence of meningitis only declined significantly in children <5 years. IPD case-fatality decreased in children <5 years from 5% to 3%, in 5-64 years old from 9% to 7% and in elderly ≥65 years significantly from 22% to 17%, due to lower case-fatality rates for most emerging non-PCV7 serotypes.

CONCLUSIONS

An increase in empyema incidence was observed in persons ≥65 years old in the post-PCV7 era, mainly due to the emergence of serotype 1, although overall IPD case-fatality decreased. Extended conjugate vaccines that target serotype 1 or serotypes with high case-fatality may offer further reduction of pneumococcal disease burden.

Pneumococcal population in the era of vaccination: changes in composition and the relation to clinical outcomes

BACKGROUND

Vaccination of infants with pneumococcal conjugate vaccines (PCV) has resulted in major shifts in circulating serotypes.

AIM

To investigate the impact of PCV7 on the clonal composition of the pneumococcal population, and the relation of clonal lineages and clinical outcome.

MATERIALS & METHODS

By using multiple-locus variable number of tandem repeat analysis, we assessed the pneumococcal populations before (n = 1154), 2-3 years after (n = 1190) and 4-6 years after (n = 1244) the introduction of PCV7 in The Netherlands.

RESULTS

We found statistically significant shifts in clonal lineages within serotypes 1 and 12F based on multiple-locus variable number of tandem repeat analysis results after the implementation of PCV7. Within serotype 12F, the increasing clonal lineage was significantly more associated with pneumonia.

CONCLUSION

Shifts in clonal lineages within serotypes could impact the outcomes of pneumococcal disease and fill the niche of the vaccine serotypes.

Direct Comparison of Immunogenicity Induced by 10- or 13-Valent Pneumococcal Conjugate Vaccine around the 11-Month Booster in Dutch Infants

BACKGROUND & AIMS

Since 2009/10, a 10- and a 13-valent pneumococcal conjugate vaccine (PCV) are available, but only the 10-valent vaccine is now being used for the children in the Netherlands. As the vaccines differ in number of serotypes, antigen concentration, and carrier proteins this study was designed to directly compare quantity and quality of the antibody responses induced by PCV10 and PCV13 before and after the 11-month booster.

METHODS

Dutch infants (n = 132) were immunized with either PCV10 or PCV13 and DTaP-IPV-Hib-HepB at the age of 2, 3, 4 and 11 months. Blood samples were collected pre-booster and post-booster at one week and one month post-booster for quantitative and qualitative immunogenicity against 13 pneumococcal serotypes, as well as quantitative immunogenicity against diphtheria, tetanus, pertussis and Haemophilus influenzae type b. We compared immunogenicity induced by PCV13 and PCV10 for their ten shared serotypes.

RESULTS

One month post-booster, pneumococcal serotype-specific IgG geometric mean concentrations (GMCs) for the PCV13 group were higher compared with the PCV10 group for six serotypes, although avidity was lower. Serotype 19F showed the most distinct difference in IgG and, in contrast to other serotypes, its avidity was higher in the PCV13 group. One week post-booster, opsonophagocytosis for serotype 19F did not differ significantly between the PCV10- and the PCV13 group.

CONCLUSION

Both PCV10 and PCV13 were immunogenic and induced a booster response. Compared to the PCV10 group, the PCV13 group showed higher levels for serotype 19F GMCs and avidity, pre- as well as post-booster, although opsonophagocytosis did not differ significantly between groups. In our study, avidity is not correlated to opsonophagocytotic activity (OPA) and correlations between IgG and OPA differ per serotype. Therefore, besides assays to determine IgG GMCs, assays to detect opsonophagocytotic activity, i.e., the actual killing of the pneumococcus, are important for PCV evaluation. How differences between the two vaccines relate to long-term protection requires further investigation.

TRIAL REGISTRATION

www.trialregister.nl NTR3069.

Nasopharyngeal carriage of Streptococcus pneumoniae and other bacteria in the 7th year after implementation of the pneumococcal conjugate vaccine in the Netherlands

After introduction of the 7-valent pneumococcal conjugate vaccine (PCV7) in the infant national immunization program (NIP) in the Netherlands in 2006, Streptococcus pneumoniae strains of the non-vaccine serotype 19A emerged and became the dominant serotype in carriage in children and their parents. Similar patterns were observed in other European countries and the United States. Increases in carriage rates of Staphylococcus aureus and non-typeable (NT) Haemophilus influenzae were also observed. After switching of PCV7 to 10-valent vaccine (PCV10) in 2011, a new carriage surveillance study was performed in the winter of 2012/2013. Nasopharyngeal carriage of S. pneumoniae, H. influenzae, S. aureus, and Moraxella catarrhalis was determined by conventional culture in 330 PCV10-vaccinated 11-month-old children, 330 PCV7-vaccinated 24-month-old children, and their parents. Carriage prevalence was compared with similar carriage studies conducted in 2005, 2009, and 2010/2011. Although serotype 19A remained the most frequently carried pneumococcal serotype in children, prevalence of 19A significantly declined in PCV7-vaccinated 24-month-old children (14% to 8%, p=0.01), but less in PCV10-vaccinated 11-month-old children (12% to 9%, p=0.31). Carriage of H. influenzae remained stable at an elevated level (65% in 11-month-olds and 69% in 24-month-olds), while the carriage of S. aureus returned to pre-PCV7 levels in 11-month-old children (14% in 2010/2011 to 7% in 2012/2013), but not in 24-month-olds (remained at 7%). Our results might indicate a new balance between replacing non-vaccine pneumococcal serotypes and other potential pathogenic bacteria in nasopharyngeal carriage. Carriage studies are valuable tools in assessing vaccine effects on pathogens circulating in the population, for evaluation of PCV impact, and in predicting changes in respiratory and invasive disease.

Community-acquired bacterial meningitis in adults in the Netherlands, 2006-14: a prospective cohort study

BACKGROUND

We studied causative pathogens, clinical characteristics, and outcome of adult community-acquired bacterial meningitis after the introduction of adjunctive dexamethasone treatment and nationwide implementation of paediatric conjugate vaccines.

METHODS

In this cohort study, we prospectively assessed adults (age >16 years) with community-acquired bacterial meningitis in the Netherlands, identified through the National Reference Laboratory for Bacterial Meningitis or individual physicians between Jan 1, 2006, and July 1, 2014. We identified independent predictors of an unfavourable outcome (Glasgow Outcome Scale score 1-4) by logistic regression.

FINDINGS

We assessed 1412 episodes of community-acquired bacterial meningitis. Incidence declined from 1·72 cases per 100,000 adults per year in 2007-08, to 0·94 per 100,000 per year in 2013-14. Streptococcus pneumoniae caused 1017 (72%) of 1412 episodes. Rates of adult bacterial meningitis decreased most sharply among pneumococcal serotypes included in paediatric conjugate vaccine, and in meningococcal meningitis. We found no evidence of serotype or serogroup replacement. The overall case fatality rate was 244 (17%) of 1412 episodes and unfavourable outcome occurred in 531 (38%) of 1412 episodes. Predictors of unfavourable outcome were advanced age, absence of otitis or sinusitis, alcoholism, tachycardia, lower score on the Glasgow Coma Scale, cranial nerve palsy, a cerebrospinal fluid white-cell count lower than 1000 cells per μL, a positive blood culture, and a high serum C-reactive protein concentration. Adjunctive dexamethasone was administered for 1234 (89%) of 1384 assessed episodes. The multivariable adjusted odds ratio of dexamethasone treatment for unfavourable outcome was 0·54 (95% CI 0·39-0·73).

INTERPRETATION

The incidence of adult bacterial meningitis has decreased substantially, which is partly explained by herd protection by paediatric conjugate vaccines. Adjunctive dexamethasone treatment was associated with substantially improved outcome.

FUNDING

European Research Council, National Institute of Public Health and the Environment, European Union, Academic Medical Center, and Netherlands Organization for Health Research and Development.

Risk and outcomes of invasive pneumococcal disease in adults with underlying conditions in the post-PCV7 era, The Netherlands

BACKGROUND

Immunocompromising conditions and advanced age (≥65 years) are associated with a high risk for invasive pneumococcal disease (IPD). We investigated the risk and outcomes of IPD in adults with underlying conditions in the post-PCV7 era in The Netherlands.

METHODS

IPD data from 2008 to 2012 was obtained from the national pneumococcal surveillance system, covering 25% of the Dutch population. Population estimates of underlying conditions were derived from the primary care data (2012). IPD incidence in adults with immunocompromising conditions (high risk group) and non-immunocompromising comorbidities (medium risk group) were compared to the "normal risk group" without diagnosed comorbidities. Case-fatality and ICU admission in the different risk groups was analyzed by logistic regression. Serotype specific propensities to affect high risk group IPD patients were calculated.

RESULTS

Adults with a high risk condition have a 18-fold (95% CI 15.6-21.2) and 3-fold (95% CI 2.6-3.9) higher risk compared to the normal risk group for IPD at age 18-64 years and 65 years and older, respectively. In case of a medium risk condition, the risk is 5-fold (95% CI 4.3-5.7) and 2-fold (95% CI 1.9-2.6) higher in age groups 18-64 and ≥65 years old. Likewise, IPD patients with a high or medium risk condition have a higher case-fatality (after adjustment for age, odds ratio: 2-fold (95% CI 1.5-3.5) and 1.4-fold (95% CI 1.0-2.1), respectively). Several serotypes (e.g. 6A, 6B, 23A and 23B) are associated with a significantly higher propensity to cause disease in high risk patients.

CONCLUSIONS

The risk for IPD and death in the post-PCV7 era has remained considerably high in adults and elderly with underlying conditions. The identification of serotypes with a high propensity to affect risk groups can be important for selecting (future) vaccine serotypes.

Longitudinal DRG-based survey of all-cause and pneumococcal pneumonia and meningitis for inpatients in France (2005-2010)

OBJECTIVE

This population-based retrospective study quantified the burden of all-cause and pneumococcal pneumonia and meningitis in the Rhône-Alpes region of France from 2005 to 2010, when the 7-valent pneumococcal conjugate vaccine uptake increased from 50 to>90% in children.

PATIENTS AND METHODS

Hospital admission data was obtained from the French Diagnosis Related Groups program database (French acronym PMSI). Patients were residents of the Rhône-Alpes region hospitalized for the diseases of interest during 2005-2010. Hospitalization and in-hospital mortality rates were calculated by age, sex, and year on the basis of the Rhône-Alpes region population. Hospitalization and in-hospital mortality rates were compared using Chi(2) tests with statistical significance adjusted for multiple comparisons.

RESULTS

The highest hospitalization rates by age group were: all-cause pneumonia, oldest group (>65 years); all-cause and pneumococcal meningitis, youngest group (0-4 years), and pneumococcal pneumonia, youngest and oldest groups. Hospitalization rates significantly decreased for all-cause pneumonia (5-19 years: -12.71%) and all-cause meningitis (20-49 years: -29.22%). Pneumococcal disease rates did not significantly change in any age group. Mortality rates from all-cause pneumonia and meningitis were highest in the oldest age groups.

CONCLUSIONS

The burden of all-cause and pneumococcal pneumonia and meningitis remains substantial. Significant changes (decreases) between 2005 and 2010 in hospitalization rates were limited and varied among age groups, most likely because this study began 2 years after PCV7 was first introduced in France for children at broadly-defined high risk. Further research is needed on the relationship between serotype epidemiology and clinical patterns of disease.

The post-vaccine microevolution of invasive Streptococcus pneumoniae

The 7-valent pneumococcal conjugated vaccine (PCV7) has affected the genetic population of Streptococcus pneumoniae in pediatric carriage. Little is known however about pneumococcal population genomics in adult invasive pneumococcal disease (IPD) under vaccine pressure. We sequenced and serotyped 349 strains of S. pneumoniae isolated from IPD patients in Nijmegen between 2001 and 2011. Introduction of PCV7 in the Dutch National Immunization Program in 2006 preluded substantial alterations in the IPD population structure caused by serotype replacement. No evidence could be found for vaccine induced capsular switches. We observed that after a temporary bottleneck in gene diversity after the introduction of PCV7, the accessory gene pool re-expanded mainly by genes already circulating pre-PCV7. In the post-vaccine genomic population a number of genes changed frequency, certain genes became overrepresented in vaccine serotypes, while others shifted towards non-vaccine serotypes. Whether these dynamics in the invasive pneumococcal population have truly contributed to invasiveness and manifestations of disease remains to be further elucidated. We suggest the use of whole genome sequencing for surveillance of pneumococcal population dynamics that could give a prospect on the course of disease, facilitating effective prevention and management of IPD.

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.

Cost-effectiveness of adult pneumococcal conjugate vaccination in the Netherlands

The Community-Acquired Pneumonia Immunization Trial in Adults (CAPiTA) demonstrated the efficacy of 13-valent pneumococcal conjugate vaccine (PCV13) in preventing vaccine-type community-acquired pneumonia and vaccine-type invasive pneumococcal disease in elderly subjects. We examined the cost-effectiveness of PCV13 vaccination in the Netherlands.

Using a Markov-type model, incremental cost-effectiveness ratios (ICER) of PCV13 vaccination in different age- and risk-groups for pneumococcal disease were evaluated using a societal perspective. Estimates of quality-adjusted life-years (QALYs), costs, vaccine efficacy and epidemiological data were based on the CAPiTA study and other prospective studies. The base-case was PCV13 vaccination of adults aged 65–74 years compared to no vaccination, assuming no net indirect effects in base-case due to paediatric 10-valent pneumococcal conjugate vaccine use. Analyses for age- and risk-group specific vaccination strategies and for different levels of hypothetical herd effects from a paediatric PCV programme were also conducted.

The ICER for base-case was €8650 per QALY (95% CI 5750–17 100). Vaccination of high-risk individuals aged 65–74 years was cost-saving and extension to medium-risk individuals aged 65–74 years yielded an ICER of €2900. Further extension to include medium- and high-risk individuals aged ≥18 years yielded an ICER of €3100.

PCV13 vaccination is highly cost-effective in the Netherlands. The transferability of our results to other countries depends upon vaccination strategies already implemented in those countries.

Vaccinating the elderly with 13-valent pneumococcal conjugate vaccine is highly cost-effectivehttp://ow.ly/NVeui

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.

Differential B-cell memory around the 11-month booster in children vaccinated with a 10- or 13-valent pneumococcal conjugate vaccine

Infants vaccinated with the 10- or 13-valent pneumococcal conjugate vaccine at 2, 3, 4, and 11 months had similar serotype-specific immunoglobulin G levels and plasma cell frequencies against 4 shared serotypes around these boosters, but higher memory B-cell frequencies in the PCV13 group.

Background. Both the 10- and 13-valent pneumococcal conjugate vaccines (PCV10 and PCV13) induce immunological memory against Streptococcus pneumoniae infections caused by vaccine serotypes. In addition to comparing serum antibody levels, we investigated frequencies of serotype-specific plasma cells (PCs) and memory B-cells (Bmems) as potential predictors of long-term immunity around the booster vaccination at 11 months of age.

Methods. Infants were immunized with PCV10 or PCV13 at 2, 3, 4, and 11 months of age. Blood was collected before the 11-month booster or 7–9 days afterward. Serotype-specific immunoglobulin G (IgG) levels were determined in serum samples by multiplex immunoassay. Circulating specific PCs and Bmems against shared serotypes 1, 6B, 7F, and 19F and against PCV13 serotypes 6A and 19A were measured in peripheral blood mononuclear cells by enzyme-linked immunospot assay.

Results. No major differences in IgG levels and PC frequencies between groups were found for the 4 shared serotypes. Notably, PCV13 vaccination resulted in higher frequencies of Bmems than PCV10 vaccination, both before and after the booster dose, for all 4 shared serotypes except for serotype 1 postbooster. For PCV13-specific serotypes 6A and 19A, the IgG levels and frequencies of PCs and Bmems were higher in the PCV13 group, pre- and postbooster, except for PC frequencies prebooster.

Conclusions. Both PCVs are immunogenic and induce measurable IgG, PC, and Bmem booster responses at 11 months. Compared to PCV10, vaccination with PCV13 was associated with overall similar IgG levels and PC frequencies but with higher Bmem frequencies before and after the 11-month booster. The clinical implications of these results need further follow-up.

Clinical Trials Registration. NTR3069.

Polysaccharide conjugate vaccine against pneumococcal pneumonia in adults

BACKGROUND

Pneumococcal polysaccharide conjugate vaccines prevent pneumococcal disease in infants, but their efficacy against pneumococcal community-acquired pneumonia in adults 65 years of age or older is unknown.

METHODS

In a randomized, double-blind, placebo-controlled trial involving 84,496 adults 65 years of age or older, we evaluated the efficacy of 13-valent polysaccharide conjugate vaccine (PCV13) in preventing first episodes of vaccine-type strains of pneumococcal community-acquired pneumonia, nonbacteremic and noninvasive pneumococcal community-acquired pneumonia, and invasive pneumococcal disease. Standard laboratory methods and a serotype-specific urinary antigen detection assay were used to identify community-acquired pneumonia and invasive pneumococcal disease.

RESULTS

In the per-protocol analysis of first episodes of infections due to vaccine-type strains, community-acquired pneumonia occurred in 49 persons in the PCV13 group and 90 persons in the placebo group (vaccine efficacy, 45.6%; 95.2% confidence interval [CI], 21.8 to 62.5), nonbacteremic and noninvasive community-acquired pneumonia occurred in 33 persons in the PCV13 group and 60 persons in the placebo group (vaccine efficacy, 45.0%; 95.2% CI, 14.2 to 65.3), and invasive pneumococcal disease occurred in 7 persons in the PCV13 group and 28 persons in the placebo group (vaccine efficacy, 75.0%; 95% CI, 41.4 to 90.8). Efficacy persisted throughout the trial (mean follow-up, 3.97 years). In the modified intention-to-treat analysis, similar efficacy was observed (vaccine efficacy, 37.7%, 41.1%, and 75.8%, respectively), and community-acquired pneumonia occurred in 747 persons in the PCV13 group and 787 persons in placebo group (vaccine efficacy, 5.1%; 95% CI, -5.1 to 14.2). Numbers of serious adverse events and deaths were similar in the two groups, but there were more local reactions in the PCV13 group.

CONCLUSIONS

Among older adults, PCV13 was effective in preventing vaccine-type pneumococcal, bacteremic, and nonbacteremic community-acquired pneumonia and vaccine-type invasive pneumococcal disease but not in preventing community-acquired pneumonia from any cause. (Funded by Pfizer; CAPITA ClinicalTrials.gov number NCT00744263.).

Detection and serotyping of pneumococci in community acquired pneumonia patients without culture using blood and urine samples

Background

Treatment of community acquired pneumonia (CAP) patients with antibiotics before laboratory-confirmed diagnosis leads to loss of knowledge on the causative bacterial pathogen. Therefore, an increasing number of pneumococcal infections is identified using non-culture based techniques. However, methods for serotyping directly on the clinical specimen remain scarce. Here we present three approaches for detection and serotyping of pneumococci using samples from patients with CAP.

Methods

The first approach is quantitative PCR (qPCR) analysis on blood samples (n = 211) followed by capsular sequence typing (CST) to identify the serotype. The second approach, a urinary antigen assay (n = 223), designated as inhibition multiplex immunoassay (IMIA), is based on Luminex technology targeting 14 serotypes. The third approach is a multiplex immunoassay (MIA) (n = 171) also based on Luminex technology which detects serologic antibody responses against 14 serotypes. The three alternative assays were performed on samples obtained from 309 adult hospitalized CAP patients in 2007–2010 and the results were compared with those obtained from conventional laboratory methods to detect pneumococcal CAP, i.e. blood cultures, sputum cultures and BinaxNOW® urinary antigen tests.

Results

Using qPCR, MIA and IMIA, we were able to detect the pneumococcus in samples of 56% more patients compared to conventional methods. Furthermore, we were able to assign a serotype to the infecting pneumococcus from samples of 25% of all CAP patients, using any of the three serotyping methods (CST, IMIA and MIA).

Conclusion

This study indicates the usefulness of additional molecular methods to conventional laboratory methods for the detection of pneumococcal pneumonia. Direct detection and subsequent serotyping on clinical samples will improve the accuracy of pneumococcal surveillance to monitor vaccine effectiveness.

Clinical burden of multi-cause and pneumococcal pneumonia, meningitis, and septicemia in Hungary. Results of a retrospective study (2006–2011)

Introduction: Assessment of the impact of pneumococcal conjugate vaccines on the burden of pneumonia, meningitis, and septicemia in Hungary is limited. Aim: The aim of this retrospective study was to quantify rates of hospitalized multi-cause and pneumococcal pneumonia, meningitis, and septicemia in all age groups in Hungary between 2006 and 2011. Method: Aggregate data were obtained from the Hungarian National Healthcare Fund using pre-specified ICD-10 codes. Comparisons included average rates pre-vaccine (2006–2007) versus post-vaccine (2010–2011) using a χ2test. Results: Hospitalization rates among children aged 0–4 years significantly declined for multi-cause pneumonia and meningitis, but increased for septicemia. There were significant increases in multi-cause pneumonia and septicemia in other age groups. In-hospital mortality rates increased with age. Limited use of pneumococcal-specific codes led to inconclusive findings for pneumococcal diseases. Conclusions: Declines in multi-cause pneumonia and meningitis in children aged 0–4 years suggest direct effects of pneumococcal conjugate vaccination on hospitalization rates. Orv. Hetil., 2014, 155(36), 1426–1436.

Bacteraemic and non-bacteraemic/urinary antigen-positive pneumococcal community-acquired pneumonia compared

The diagnosis of invasive pneumococcal pneumonia is based mainly on bacteraemia. Episodes without bacteraemia, but with a positive urinary antigen test (UAT), are considered non-invasive. We determined differences in outcome between patients with bacteraemic and non-bacteraemic/UAT-positive pneumococcal community-acquired pneumonia (CAP). Adult patients with clinical and radiological evidence of CAP with blood cultures and UAT tests performed at presentation in three Dutch laboratories between June 2008 and May 2010 were included. Clinical characteristics were retrospectively extracted from hospital records. Overall, 168 patients had non-bacteraemic/UAT-positive pneumococcal CAP and 123 had bacteraemic pneumococcal CAP. The day-30 mortality was 9% and 13% for non-bacteraemic/UAT-positive and bacteraemic pneumococcal CAP patients, respectively [risk difference -4%, 95% confidence interval (CI) -11% to +3%, p = 0.28]. In a multivariable logistic regression model, age ≥ 65 years, admission to the intensive care unit/coronary care unit (ICU/CCU) and presence of an immunocompromising condition were associated with day-30 mortality. A non-significant association with mortality was found for bacteraemia [odds ratio (OR) 2.21, 95% CI 0.94-5.21, p = 0.07). No such trend was found for UAT positivity. The median lengths of hospital stay were 8 [interquartile range (IQR) 5-14] and 10 (IQR 6-18) days for non-bacteraemic/UAT-positive and bacteraemic pneumococcal CAP patients, respectively (p = 0.05). As compared to non-bacteraemic/UAT-positive pneumococcal CAP, bacteraemic pneumococcal CAP has a stronger association with day-30 mortality.

Experience with pneumococcal polysaccharide conjugate vaccine (conjugated to CRM197 carrier protein) in children and adults

Streptococcus pneumoniae-related infections are a major cause of morbidity and mortality in people of all ages worldwide. Pneumococcal vaccine development started in 1911 with a whole cell vaccine and more recently multivalent plain polysaccharide and polysaccharide conjugate vaccines have been developed. The recent vaccines rely on capsular polysaccharide antigens to induce serotype-specific immune responses. We summarize here the presentations on pneumococcal polysaccharide conjugate vaccine (conjugated to CRM197 carrier protein) given during the integrated symposium organized and funded by Pfizer International Operations during the 22nd European Congress of Clinical Microbiology and Infectious Diseases (ECCMID) 31 March to 3 April 2012, London, UK. A dramatic reduction in the incidence of invasive pneumococcal diseases (IPD) due to vaccine serotypes (VST-IPD) has been reported since the introduction of a hepta-valent pneumococcal conjugate vaccine (PCV7). An indirect (herd) effect has been demonstrated to be associated with PCV7 infant vaccination programmes, with many studies reporting reductions in VST-IPD in populations that are not eligible for PCV7 vaccination. Since 2010, a 13-valent pneumococcal conjugate vaccine (PCV13) has been introduced into national immunization programmes and results from early surveillance suggest that this vaccine also has an impact on the serotypes unique to PCV13, as well as continuing to protect against the PCV7 serotypes. Data from a passive surveillance system in Europe in 2009, for instance, showed that the highest incidence of IPD remains in those aged >65 years and in children <5 years. PCV13 has now been licensed for vaccination of adults >50 years based on safety and immunogenicity data; an efficacy trial is being conducted. Regardless of previous pneumococcal vaccination status, if the use of 23-valent polysaccharide is considered appropriate, it is recommended to give PCV13 first. Novel immunization strategies remain the only practical means to reduce significantly the remaining global mortality and morbidity due to S. pneumoniae in adults.

Effects of 7-valent pneumococcal conjugate 1 vaccine on the severity of adult 2 bacteremic pneumococcal pneumonia

PURPOSE

The introduction of a 7-valent conjugate pneumococcal vaccine (PCV7) in children largely affected the prevalence of adult pneumococcal pneumonia. In this study we investigated whether the clinical severity of adult bacteremic pneumococcal pneumonia has also altered following the introduction of pediatric PCV7 vaccination.

METHODS

Adults hospitalized with bacteremic pneumococcal pneumonia between 2001 and June 2011 at two Dutch hospitals were included retrospectively. Clinical data on patient characteristics, comorbidities and severity of disease were obtained and pneumococcal serotypes were determined.

RESULTS

Among 343 patients investigated, those infected with PCV7 serotypes had a higher PSI score (p=0.0072) and mortality rate (p=0.0083) compared with the remainder of the cohort. Since the introduction of PCV7 the proportion of pneumococcal pneumonias caused by serotypes 1 and 7F (p-values 0.037 and 0.025) increased, as well as the rate of pleural effusion and empyema (p-values 0.011 and 0.049). Whilst de proportion of adults infected with PCV7 serotypes decreased after the introduction of PCV7 (p=0.015), PSI scores in these patients remained higher (p=0.030), although mortality rates between PCV7 and non PCV7 types equalized. After the introduction of PCV7 a marked shortening in hospital stay was observed only among patients infected with non PCV7 serotypes (p=0.019).

CONCLUSIONS

The introduction of pediatric PCV7 vaccination was accompanied by subtle changes in clinical severity of adult bacteremic pneumococcal pneumonia. Expansion of serotypes covered by pneumococcal vaccination may again influence the clinical presentation of disease.