A review of evidence for pneumococcal vaccination in adults at increased risk of pneumococcal disease: risk group definitions and optimization of vaccination coverage in the United Kingdom

INTRODUCTION

Pneumococcal disease (PD) significantly contributes to morbidity and mortality, carrying substantial economic and public health burden. This article is a targeted review of evidence for pneumococcal vaccination in the UK, the definitions of groups at particular risk of PD and vaccine effectiveness.

AREAS COVERED

Relevant evidence focusing on UK data from surveillance systems, randomized controlled trials, observational studies and publicly available government documents is collated and reviewed. Selected global data are included where appropriate.

EXPERT OPINION

National vaccination programs have reduced the incidence of vaccine-type PD, despite the rising prominence of non-vaccine serotypes in the UK. The introduction of higher-valency conjugate vaccines provides an opportunity to improve protection against PD for adults in risk groups. Several incentives are in place to encourage general practitioners to vaccinate risk groups, but uptake is low-suboptimal particularly among at-risk individuals. Wider awareness and understanding among the public and healthcare professionals may increase vaccination uptake and coverage. National strategies targeting organizational factors are urgently needed to achieve optimal access to vaccines. Finally, identifying new risk factors and approaches to risk assessment for PD are crucial to ensure those at risk of PD can benefit from pneumococcal vaccination.

Cost-effectiveness of using a 20-valent pneumococcal conjugate vaccine to directly protect adults in England at elevated risk of pneumococcal disease

OBJECTIVES

Despite the current pneumococcal vaccination program in England for older adults and adults with underlying conditions, disease burden remains high. We evaluated cost-effectiveness of 20-valent pneumococcal conjugate vaccine (PCV20) compared to current pneumococcal recommendations for adults in England.

METHODS

Lifetime outcomes/costs of invasive pneumococcal disease (IPD) and community-acquired pneumonia (CAP) among adults aged 65-99 years and adults aged 18-64 years with underlying conditions in England were projected using a probabilistic cohort model. Vaccination with PCV20 was compared with 23-valent pneumococcal polysaccharide vaccine (PPV23) from the National Health Service perspective.

RESULTS

PCV20 was cost saving compared with PPV23 in base case and most sensitivity analyses. In the base case, replacing PPV23 with PCV20 prevented 7,789 and 140,046 cases of IPD and hospitalized CAP, respectively, and 22,199 associated deaths, resulting in incremental gain of 91,375 quality-adjusted life-years (QALYs) and incremental savings of £160M. In probabilistic sensitivity analyses, PCV20 (vs. PPV23) was cost saving in 85% of simulations; incremental cost per QALY was below £30,000 in 99% of simulations.

CONCLUSIONS

PCV20 vaccination in adults aged 65-99 years and those aged 18-64 years with underlying comorbidities in England is expected to prevent more hospitalizations, save more lives, and yield lower overall costs than current recommendations for PPV23.

Public health and budgetary impact of 20-valent pneumococcal conjugate vaccine for adults in England

BACKGROUND

. Despite use of 23-valent pneumococcal polysaccharide vaccine (PPV23) in England, disease burden among at-risk adults remains high. We evaluated the public health and budgetary impact of 20-valent pneumococcal conjugate vaccine (PCV20) compared to the current adult pneumococcal vaccination program.

METHODS

Five-year outcomes and costs of invasive pneumococcal disease (IPD) and community-acquired pneumonia (CAP) among adults aged 65-99 years and adults aged 18-64 years with underlying conditions in England were projected using a deterministic cohort model. Hypothetical vaccination with PCV20 versus PPV23 was compared from National Health Service (NHS) perspective.

RESULTS

Replacing PPV23 with PCV20 would prevent 785 IPD hospitalizations, 11,751 CAP hospitalizations, and 1,414 deaths over five years, and would reduce medical care costs by £48.5M. With vaccination costs higher by £107.2M, projected net budgetary impact is £58.7M. The budgetary impact would be greatest in year one (£26.3M), and would decrease over time (to £1.6M by year five). The average budget increase (£11.7M/year) represents <0.01% of the Department of Health and Social Care budget and <3% of the vaccines budget.

CONCLUSIONS

Use of PCV20 among adults currently eligible for PPV23 in England would substantially reduce the burden of pneumococcal disease, with modest budgetary impact.

A review of current data to support decision making for introduction of next generation higher valency pneumococcal conjugate vaccination of immunocompetent older adults in the UK

INTRODUCTION

The burden of pneumococcal disease in older UK adults remains substantial. Higher valency pneumococcal conjugate vaccines (PCVs) are currently in development with adult formulations for two of these anticipated to become available in 2022. This article collates and reviews relevant candidate data now available that may be used to support cost effectiveness assessments of vaccinating immunocompetent UK adults aged ≥65-years with PCVs.

AREAS COVERED

This article uses published data from surveillance systems, randomized controlled trials and observational studies. It focuses on local data from the UK but where these are either limited or not available relevant global data are considered.

EXPERT OPINION

The body of relevant data now available suggests the UK is well placed to assess the cost effectiveness of vaccinating immunocompetent ≥65-year olds with new generation higher valency PCVs. Recent contemporary data provide important new and robust insights into the epidemiology of pneumococcal disease in older UK adults and help to address much of the uncertainty and data gaps associated with previous analyses. Using these data to make informed decisions about use of new higher valency PCVs for routine use in older adults will be important for public health in the UK.

The Global Landscape of Pediatric Bacterial Meningitis Data Reported to the World Health Organization-Coordinated Invasive Bacterial Vaccine-Preventable Disease Surveillance Network, 2014-2019

BACKGROUND

The World Health Organization (WHO) coordinates the Global Invasive Bacterial Vaccine-Preventable Diseases (IB-VPD) Surveillance Network to support vaccine introduction decisions and use. The network was established to strengthen surveillance and laboratory confirmation of meningitis caused by Streptococcus pneumoniae, Haemophilus influenzae, and Neisseria meningitidis.

METHODS

Sentinel hospitals report cases of children <5 years of age hospitalized for suspected meningitis. Laboratories report confirmatory testing results and strain characterization tested by polymerase chain reaction. In 2019, the network included 123 laboratories that follow validated, standardized testing and reporting strategies.

RESULTS

From 2014 through 2019, >137 000 suspected meningitis cases were reported by 58 participating countries, with 44.6% (n = 61 386) reported from countries in the WHO African Region. More than half (56.6%, n = 77 873) were among children <1 year of age, and 4.0% (n = 4010) died among those with reported disease outcome. Among suspected meningitis cases, 8.6% (n = 11 798) were classified as probable bacterial meningitis. One of 3 bacterial pathogens was identified in 30.3% (n = 3576) of these cases, namely S. pneumoniae (n = 2177 [60.9%]), H. influenzae (n = 633 [17.7%]), and N. meningitidis (n = 766 [21.4%]). Among confirmed bacterial meningitis cases with outcome reported, 11.0% died; case fatality ratio varied by pathogen (S. pneumoniae, 12.2%; H. influenzae, 6.1%; N. meningitidis, 11.0%). Among the 277 children who died with confirmed bacterial meningitis, 189 (68.2%) had confirmed S. pneumoniae. The proportion of pneumococcal cases with pneumococcal conjugate vaccine (PCV) serotypes decreased as the number of countries implementing PCV increased, from 77.8% (n = 273) to 47.5% (n = 248). Of 397 H. influenzae specimens serotyped, 49.1% (n = 195) were type b. Predominant N. meningitidis serogroups varied by region.

CONCLUSIONS

This multitier, global surveillance network has supported countries in detecting and serotyping the 3 principal invasive bacterial pathogens that cause pediatric meningitis. Streptococcus pneumoniae was the most common bacterial pathogen detected globally despite the growing number of countries that have nationally introduced PCV. The large proportions of deaths due to S. pneumoniae reflect the high proportion of meningitis cases caused by this pathogen. This global network demonstrated a strong correlation between PCV introduction status and reduction in the proportion of pneumococcal meningitis infections caused by vaccine serotypes. Maintaining case-based, active surveillance with laboratory confirmation for prioritized vaccine-preventable diseases remains a critical component of the global agenda in public health.The World Health Organization (WHO)-coordinated Invasive Bacterial Vaccine-Preventable Disease (IB-VPD) Surveillance Network reported data from 2014 to 2019, contributing to the estimates of the disease burden and serotypes of pediatric meningitis caused by Streptococcus pneumoniae, Haemophilus influenzae and Neisseria meningitidis.

Identifying UK travellers at increased risk of developing pneumococcal infection: a novel algorithm

BACKGROUND

In 2016, the travel subcommittee of the UK Joint Committee on Vaccination and Immunisation (JCVI) recommended that 13-valent PCV (PCV13) could be offered to travellers aged over 65 years, visiting countries without infant PCV immunization programmes. This study aimed to identify, collate and review the available evidence to identify specific countries where UK travellers might be at an increased risk of developing pneumococcal infection. The data were then used to develop an algorithm, which could be used to facilitate implementation of the JCVI recommendation.

METHODS

We conducted a systematic search of the published data available for pneumococcal disease, PCV vaccine implementation, coverage data and programme duration by country. The primary data sources used were World Health Organization databases and the International Vaccine Access Centre Vaccine Information and Epidemiology Window-hub database. Based on the algorithm, the countries were classified into 'high overall risk', 'intermediate overall risk' and 'low overall risk' from an adult traveller perspective. This could determine whether PCV13 should be recommended for UK adult travellers.

RESULTS

A data search for a total of 228 countries was performed, with risk scores calculated for 188 countries. Overall, 45 countries were classified as 'high overall risk', 86 countries as 'intermediate overall risk', 57 countries as 'low overall risk' and 40 countries as 'unknown'.

CONCLUSION

To our knowledge this is the first attempt to categorize the risk to UK adult travellers of contracting pneumococcal infection in each country, globally. These findings could be used by national travel advisory bodies and providers of travel vaccines to identify travellers at increased risk of pneumococcal infection, who could be offered PCV immunization.

Systematic literature review of the impact and effectiveness of monovalent meningococcal C conjugated vaccines when used in routine immunization programs

BACKGROUND

Monovalent meningococcal C conjugate vaccine (MCCV) was introduced into the routine immunization program in many countries in Europe and worldwide following the emergence of meningococcal serogroup C (MenC) in the late 1990s. This systematic literature review summarizes the immediate and long-term impact and effectiveness of the different MCCV vaccination schedules and strategies employed.

METHODS

We conducted a systematic literature search for peer-reviewed, scientific publications in the databases of MEDLINE (via PubMed), LILACS, and SCIELO. We included studies from countries where MCCV have been introduced in routine vaccination programs and studies providing the impact and effectiveness of MCCV published between 1st January 2001 and 31st October 2017.

RESULTS

Forty studies were included in the review; 30 studies reporting impact and 17 reporting effectiveness covering 9 countries (UK, Spain, Italy, Canada, Brazil, Australia, Belgium, Germany and the Netherlands). Following MCCV introduction, significant and immediate reduction of MenC incidence was consistently observed in vaccine eligible ages in all countries with high vaccine uptake. The reduction in non-vaccine eligible ages (especially population > 65 years) through herd protection was generally observed 3-4 years following introduction. Vaccine effectiveness (VE) was mostly assessed through screening methods and ranged from 38 to 100%. The VE was generally highest during the first year after vaccination and waned over time. The VE was better maintained in countries employing catch-up campaigns in older children and adolescents, compared to routine infant only schedules.

CONCLUSIONS

MCCV were highly effective, showing a substantial and sustained decrease in MenC invasive meningococcal disease. The epidemiology of meningococcal disease is in constant transition, and some vaccination programs now include adolescents and higher valent vaccines due to the recent increase in cases caused by serogroups not covered by MCCV. Continuous monitoring of meningococcal disease is essential to understand disease evolution in the setting of different vaccination programs.

Clinical and financial burden of hospitalised community-acquired pneumonia in patients with selected underlying comorbidities in England

Background

Hospitalised pneumonia may have long-term clinical and financial impact in adult patients with underlying comorbidities.

Methods

We conducted a retrospective cohort study using the Hospital Episode Statistics (HES) database to determine the clinical and financial burden over 3 years of hospitalised community-acquired pneumonia (CAP) to England’s National Health Service (NHS). Subjects were adults with six underlying comorbidities (chronic heart disease (CHD); chronic kidney disease (CKD); chronic liver disease (CLD); chronic respiratory disease (CRD); diabetes mellitus (DM) and post bone marrow transplant (post-BMT)) with an inpatient admission in 2012/2013. Patients with CAP in 2013/2014 were followed for 3 years and compared with similarly aged, propensity score-matched adults with the same comorbidity without CAP.

Findings

The RR of hospital admissions increased after CAP, ranging from 1.08 (95% CI 1.04 to 1.12) for CKD to 1.38 (95% CI 1.35 to 1.40) for CRD. This increase was maintained for at least 2 years. Mean difference in hospital healthcare costs (£) was higher for CAP patients in 2013/2014; ranging from £1115 for DM to £8444 for BMT, and remained higher for 4/6 groups for 2 more years, ranging from £1907 (95% CI £1573 to £2240) for DM to £11 167 (95% CI £10 847 to £11 486) for CRD.) The OR for mortality was significantly higher for at least 3 years after CAP, ranging from 4.76 (95% CI 4.12 to 5.51, p<0.0001) for CLD to 7.50 (95%CI 4.71 to 11.92, p<0.0001) for BMT.

Interpretation

For patients with selected underlying comorbidities, healthcare utilisation, costs and mortality increase for at least 3 years after being hospitalised CAP.

Haemophilus influenzae type b disease in the era of conjugate vaccines: critical factors for successful eradication

INTRODUCTION

Prior to implementation of Haemophilus influenzae type b (Hib)-conjugate vaccination programs in the 1990s, Hib was the commonest cause of bacterial meningitis in children aged <5 years. While the burden of all Hib disease has significantly decreased in the post-vaccination era, Hib still accounted for >29,000 deaths worldwide in children aged <5 years in 2015.

AREAS COVERED

We reviewed literature data on the most widely used Hib vaccines and vaccination strategies which led to the global prevention and control of Hib disease and aim to highlight important factors for continued disease control and elimination in the future.

EXPERT COMMENTARY

More than 90% of countries worldwide have implemented Hib-conjugate vaccination in their national immunization programs. Vaccines containing Hib polyribosylribitol phosphate (PRP) conjugated with tetanus toxoid (Hib-TT) are the most commonly used. Neisseria meningitidis outer membrane protein complex of PRP (Hib-OMP) is also used. Although the kinetics of the immune response varies with Hib vaccine and schedule used, high control of Hib disease was observed in all settings/scenarios. Further improving global Hib vaccination coverage may result in disease elimination. Plain language summary What is the context? Haemophilus influenzae is causing a variety of diseases, from otitis media and sinusitis to invasive disease (e.g. meningitis and pneumonia). H. influenzae type b (Hib) was the most common cause of bacterial meningitis in children <5 years of age, and especially among <2-year-olds. Even with appropriate treatment, up to 40% of children with bacterial meningitis can suffer permanent disabilities and up to 5% will die. The development of vaccines to protect against Hib disease has started in the late 1970s and has culminated with the licensure of 4 Hib conjugate vaccines, of which 2 are currently widely used. What is new? In this review, we gathered evidence on the different Hib vaccines and vaccination strategies that have contributed to the global prevention and control of Hib disease. The review indicates: the incidence of Hib disease has decreased considerably due to the introduction of Hib vaccines in national immunization programs worldwide. However, Hib disease is not yet completely eradicated. the vaccines currently used offer protection against Hib over long periods of time. carriage of the pathogen by healthy individuals seem to be less frequent, but data are still needed to fully evaluate the impact of vaccination. other H. influenzae types are now more frequent. Why is this important? Despite the huge success of Hib vaccination, continuous surveillance is needed to anticipate potential re-emergences and devise the best strategies for prevention and control of disease. Hib vaccination should be considered in the few countries who have not yet implemented it, to decrease associated morbidity and mortality.

Childhood Deaths Attributable to Invasive Pneumococcal Disease in England and Wales, 2006-2014

Background

Pneumococcal conjugate vaccines (PCVs) are highly effective in preventing invasive pneumococcal disease (IPD), but deaths due to IPD still occur. We aimed to describe children who died of IPD since PCV introduction in England and Wales.

Methods

Public Health England conducts enhanced IPD surveillance in England and Wales. IPD cases in PCV-eligible children aged <5 years (born since 4 September 2004 and diagnosed between 4 September 2006 and 3 September 2014) were actively followed up by postal questionnaires and, for fatal cases, detailed information was requested prospectively from multiple sources.

Results

During the 8-year period, there were 3146 IPD cases and 150 IPD-related deaths (case fatality rate, 4.8%). Overall, 132 isolates from fatal cases were serotyped (88%) and 35 distinct serotypes were identified, with no serotype predominance. Most deaths occurred in children aged <1 year (88/150 [59%]) and 1-year-olds (36/150 [24%]). One-third (53/150 [35%]) had a known risk factor for IPD. Clinical presentation varied with age but not by serotypes in the different conjugate vaccines. Meningitis was diagnosed in nearly half the fatal cases (71/150 [47%]). The IPD-related mortality rate declined after 7-valent PCV introduction from 1.25/100000 children in 2006-2007 to 0.60/100000 in 2009-2010, with a further reduction following 13-valent PCV introduction from April 2010 to 0.39/100000 in 2013-2014 (14 deaths; incidence rate ratio, 0.31 [95% confidence interval, .16-.61]; P = .0003), when most deaths were due to nonvaccine serotypes or in neonates.

Conclusions

Most fatal IPD cases are currently not vaccine-preventable. Additional strategies will be required to reduce childhood pneumococcal deaths in countries with established pneumococcal vaccination programs.

Community-acquired pneumonia in the United Kingdom: a call to action

Pneumococcal disease has a high burden in adults in the United Kingdom (UK); however, the total burden is underestimated, principally because most cases of community-acquired pneumonia (CAP) are non-invasive. Research into pneumonia receives poor funding relative to its disease burden (global mortality, disability-adjusted life years, and years lived with disability), ranking just 20 out of 25 for investment in infectious diseases in the UK. The current accuracy of data for establishing incidence rates is questionable, and it is a reflection of the paucity of research that much of the background information available derives from nearly 30 years ago. Given the relationship between CAP and mortality (pneumonia accounts for 29,000 deaths per annum in the UK, and 5-15% of patients hospitalised with CAP die within 30 days of admission), and the increasing threat of antimicrobial resistance associated with inappropriate antibiotic prescribing, such neglect of a highly prevalent problem is concerning. In this Call to Action, we explore the poorly understood burden of CAP in the UK, discuss the importance of an accurate diagnosis and appropriate treatment, and suggest how national collaboration could improve the management of an often life-threatening, yet potentially preventable disease.

Increased incidence of adult pneumococcal pneumonia during school holiday periods

Child contact is a recognised risk factor for adult pneumococcal disease. Peaks in invasive pneumococcal disease incidence observed during winter holidays may be related to changes in social dynamics. This analysis was conducted to examine adult pneumococcal community-acquired pneumonia (CAP) incidence during school holiday periods.

Between September 2008 and 2013, consecutive adults admitted to hospitals covering the Greater Nottingham area with a diagnosis of CAP were studied. Pneumococcal pneumonia was detected using culture and antigen detection methods.

Of 2221 adults studied, 575 (25.9%) were admitted during school holidays and 643 (29.0%) had pneumococcal CAP. CAP of pneumococcal aetiology was significantly more likely in adults admitted during school holidays compared to term time (35.3% versus 26.7%; adjusted OR 1.38, 95% CI 1.11–1.72, p=0.004). Over the 5-year period, the age-adjusted incidence of hospitalised pneumococcal CAP was higher during school holidays compared to term time (incident rate ratio 1.35, 95% CI 1.14–1.60, p<0.001); there was no difference in rates of all-cause CAP or non-pneumococcal CAP. Reported child contact was higher in individuals with pneumococcal CAP admitted during school holidays compared to term time (42.0% versus 33.7%, OR 1.43, 95% CI 1.00–2.03, p=0.046).

Further study of transmission dynamics in relation to these findings and to identify appropriate intervention strategies is warranted.

School holiday periods are associated with an increased incidence of adult pneumococcal community-acquired pneumoniahttp://ow.ly/JiAb3089Gii

Children with Haemophilus influenzae type b (Hib) vaccine failure have long-term bactericidal antibodies against virulent Hib strains with multiple capsular loci

Children who develop invasive Haemophilus influenzae serotype b (Hib) disease after immunisation with a highly-effective conjugate vaccine are more likely to have been infected with Hib strains possessing multiple copies of the capsulation locus. Using a recently-validated serum bactericidal antibody (SBA) assay, we tested convalescent sera from 127 Hib vaccine failure cases against clinical Hib strains expressing 1-5 copies of the capsulation locus. SBA titres correlated weakly with anti-capsular IgG antibody concentrations and there was no association between SBA geometric mean titres and number of capsulation locus copies. After infection, children with Hib vaccine failure were equally protected against Hib strains with 1-5 copies of the capsulation locus.

Impact of infant 13-valent pneumococcal conjugate vaccine on serotypes in adult pneumonia

Infant 13-valent pneumococcal conjugate vaccination (PCV13) was introduced to the UK in 2010. Its impact on serotypes implicated in adult non-bacteraemic pneumococcal pneumonia is not known. Beginning in 2008, a 5-year prospective cohort study of adults admitted to hospital with community-acquired pneumonia (CAP) was conducted. Pneumococcal serotype was established using a validated multiplex immunoassay (Bio-Plex; Bio-Rad, Hercules, CA, USA). The overall incidence for hospitalised CAP and pneumococcal CAP was 79.9 (95% CI 76.6-83.3) and 23.4 (95% CI 21.6-25.3) per 100,000 population, respectively. A decline in CAP (incidence rate ratio (IRR) per year 0.96, 95% CI 0.94-0.99; p=0.016) and pneumococcal CAP (IRR per year 0.84, 95% CI 0.80-0.89; p<0.001) was observed over the 5-year period of the study. Between the pre- and post-PCV13 periods of the study, the incidence of CAP due to serotypes included in the PCV7 declined by 88% (IRR 0.12, 95% CI 0.08-0.20; p<0.001), and CAP due to the additional 6 serotypes in PCV13 declined by 30% (IRR 0.70, 95% CI 0.51-0.96; p=0.024). Incidence of adult pneumococcal pneumonia declined over the last 5 years, with serotypes included in PCV13 declining post-PCV13 introduction, indicating early herd protection effects from PCV13 infant vaccination on adult non-bacteraemic disease. These effects may accrue over the coming years with implications for national pneumococcal vaccination policies in adults.

Serotype-specific effectiveness and correlates of protection for the 13-valent pneumococcal conjugate vaccine: a postlicensure indirect cohort study

BACKGROUND

Efficacy of the 13-valent pneumococcal conjugate vaccine (PCV13) was inferred before licensure from an aggregate correlate of protection established for the seven-valent vaccine (PCV7). We did a postlicensure assessment of serotype-specific vaccine effectiveness and immunogenicity in England, Wales, and Northern Ireland to derive the correlates of protection for individual serotypes.

METHODS

We assessed vaccine effectiveness against invasive pneumococcal disease using the indirect cohort method. We measured serotype-specific IgG concentration in infants after they were given two priming doses of PCV7 (n=126) or PCV13 (n=237) and opsonophagocytic antibody titre from a subset of these infants (n=100). We derived correlates of protection by relating percentage protection to a threshold antibody concentration achieved by an equivalent percentage of infants. We used multivariable logistic regression to estimate vaccine effectiveness and reverse cumulative distribution curves to estimate correlates of protection.

FINDINGS

For the 706 cases of invasive pneumococcal disease included in the study, PCV13 vaccine effectiveness after two doses before age 12 months or one dose from 12 months was 75% (95% CI 58-84). Vaccine effectiveness was 90% (34-98) for the PCV7 serotypes and 73% (55-84) for the six additional serotypes included in PCV13. Protection was shown for four of the six additional PCV13 serotypes (vaccine effectiveness for serotype 3 was not significant and no cases of serotype 5 infection occurred during the observation period). The vaccine effectiveness for PCV13 and PCV7 was lower than predicted by the aggregate correlate of protection of 0·35 μg/mL used during licensing. Calculated serotype-specific correlates of protection were higher than 0·35 μg/mL for serotypes 1, 3, 7F, 19A, 19F, and lower than 0·35 μg/mL for serotypes 6A, 6B, 18C, and 23F. Opsonophagocytic antibody titres of 1 in 8 or higher did not predict protection.

INTERPRETATION

PCV13 provides significant protection for most of the vaccine serotypes. Although use of the aggregate correlate of protection of 0·35 μg/mL has enabled the licensing of effective new PCVs, serotype-specific correlates of protection vary widely. The relation between IgG concentration after priming and long-term protection needs to be better understood.

FUNDING

Public Health England and UK Department of Health Research and Development Directorate.

Clinical features of adults with seven-valent-conjugated-vaccine-serotype pneumococcal pneumonia

BACKGROUND

Despite the reduction in adult invasive pneumococcal disease through 'herd protection' consequent to the introduction of childhood pneumococcal conjugate vaccination (PCV), a significant proportion of adults continue to develop pneumococcal pneumonia caused by one of the seven serotypes included in the seven-valent conjugated pneumococcal vaccine (PCV7). The clinical features and outcomes of these adults have not been previously reported.

METHODS

Adults recruited over a three year period to a large prospective cohort study of community acquired pneumonia (CAP) were investigated for pneumococcal serotypes using a validated multiplex immunoassay (Bio-plex). The baseline characteristics and outcomes of adults with PCV7-serotype CAP in comparison to those with non-PCV7-serotype CAP were established.

RESULTS

Pneumococcal aetiology was identified in 415 of 1166 (35.6%) individuals, and a serotype determined in 287 (69.2%). Following exclusion of three individuals with both a PCV7 and non-PCV7 serotype, 77 of the remaining 284 (27.1%) adults had CAP due to PCV7 serotypes. Adults with PCV7-serotype CAP were older (median years (inter-quartile range) 73.3 (60.8-84.4) versus 65.0 (46.1-78.0); p=0.001) and were more likely to have a World Health Organisation performance status ≥1 (odds ratio (OR) 2.05, 95% confidence interval (CI) 1.21-3.50).The presence of stroke (adjusted OR 2.84, 95% CI 1.36-5.95) and dementia (adjusted OR 3.55, 95% CI 1.26-9.94) as underlying co-morbid illnesses were independently associated with PCV7-serotype CAP; 30-day mortality was significantly greater in adults with PCV7-serotype CAP (adjusted OR 4.38, 95% CI 1.85-10.34).

CONCLUSION

A significant proportion of adults continue to develop PCV7-serotype CAP in the era of childhood pneumococcal conjugate vaccination. These adults are more likely to have stroke and dementia as underlying co-morbid illnesses, and have a higher 30-day mortality. A combination of pneumococcal transmission factors, host factors and pneumococcal serotype specific characteristics are likely to explain these findings.

Investigating the role of pneumococcal neuraminidase A activity in isolates from pneumococcal haemolytic uraemic syndrome

Streptococcus pneumoniae diseases are a rare but increasingly recognized trigger of atypical haemolytic uraemic syndrome (HUS) in young children and associated with a higher mortality rate than diarrhoea-associated HUS. This study aimed to determine the importance of neuraminidase A (NanA) and genomic diversity in the pathogenesis of pneumococcal HUS (pHUS). We investigated the nanA gene sequence, gene expression, neuraminidase activity and comparative genomic hybridization of invasive pneumococcal disease (IPD) isolates from patients with pHUS and control strains matched by serotype and sequence type (ST), isolated from patients with IPD but not pHUS. The nanA sequence of 33 isolates was determined and mutations at 142 aa positions were identified. High levels of diversity were observed within the NanA protein, with mosaic blocks, insertions and repeat regions present. When comparing nanA allelic diversity with ST and disease profile in the isolates tested, nanA alleles clustered mostly by ST. No particular nanA allele was associated with pHUS. There was no significant difference in overall neuraminidase activity between pHUS isolates and controls when induced/uninduced with N-acetylneuraminic acid. Comparative genomic hybridization showed little difference in genetic content between the pHUS isolates and the controls. Results of gene expression studies identified 12 genes differentially regulated in all pHUS isolates compared with the control. Although neuraminidase enzyme activity may be important in pHUS progression and contribute to pathogenesis, the lack of a distinction between pHUS isolates and controls suggests that host factors, such as acquired abnormalities of the alternative complement cascade in young children, may play a more significant role in the outcome of pHUS.

Pregnancy outcome after elective cervical cerclage in relation to type of suture material used

Cervical weakness is an important cause of late miscarriage and extreme preterm labour. Women have been traditionally offered a cervical cerclage procedure, though studies failed to demonstrate a therapeutic effect. None of these studies has addressed the effect of non-braided to braided suture material on cerclage outcome. Type of suture material is an important determinant of surgical outcomes. This issue is of particular relevance to cerclage because the traditionally braided suture has been associated with increased risk of infection in other surgical procedures. Indeed, infection is an important underlying cause for cerclage failure. It is for this reason that some surgeons use non-braided suture material. Therefore, we hypothesise that the unrealised benefit of cervical cerclage is at least in part due to the type of suture material used. In this article, we present the rationale behind our hypothesis and a proposed way of testing it.

Bacterial bronchitis caused by Streptococcus pneumoniae and nontypable Haemophilus influenzae in children: the impact of vaccination

BACKGROUND

Protracted bacterial bronchitis is a major cause of persistent cough in childhood. The organisms most commonly isolated are nontypable Haemophilus influenzae and Streptococcus pneumoniae . There are no studies addressing typing of these organisms when recovered from the lower airways.

METHODS

Isolates of these two organisms (identified in BAL samples from children undergoing routine investigation of a chronic cough thought to be attributable to a protracted bacterial bronchitis) were subject to typing. Samples were collected in Sheffield, England, and Athens, Greece. The majority of the children from Sheffield had received pneumococcal-conjugate vaccines 7 or 13 (PCV-7 or PCV-13) conjugate vaccine but only a minority of Greek children had received PCV-7.

RESULTS

All 18 S pneumoniae isolates from Greek BAL samples are serotypes contained in PCV-13 while 10 are contained in PCV-7. In contrast, 28 of the 39 samples from Sheffield contained serotypes that are not included in PCV-13. All 26 of the nontypable H influenzae samples obtained in Sheffield produced distinct multilocus variable-number tandem repeat analysis profiles. There was a significant difference between children from Athens and Sheffield in the distribution of serotypes contained or not contained in the pneumococcal vaccine ( P = .04). More specifically, immunization with pneumococcal vaccine was related with isolation of S pneumoniae serotypes not included in the vaccine (OR, 0.021; CI, 0.003-0.115; P < .001).

CONCLUSIONS

The data suggest that both vaccine and nonvaccine S pneumoniae serotypes may play a role in protracted bacterial bronchitis and provide some hints that serotype replacement may occur in response to the introduction of conjugate vaccines.

A randomised controlled trial of abdominal versus laparoscopic sacrocolpopexy for the treatment of post-hysterectomy vaginal vault prolapse: LAS study

INTRODUCTION AND HYPOTHESIS

This prospective multi-centre true two-sided equivalence trial was designed to test the clinical equivalence of open (ASCP) and laparoscopic (LSCP) sacrocolpopexy using objective and subjective outcomes

METHODS

The study was carried out in three urogynaecology units in England, UK and the patient population consisted of women referred with symptomatic and bothersome post-hysterectomy vaginal vault prolapse at least 1 cm above or beyond the hymeneal remnants. The interventions were either abdominal or laparoscopic sacrocolpopexy following randomisation to one of the types of surgery.

RESULTS

For the primary outcome (point C on the POP-Q) the results at 1 year were -6.63 cm for the open ASCP and -6.67 cm for the LSCP respectively. Subjective outcomes at 1 year showed that 90% of the ASCP group and 80% of the LSCP group were "much better". There were improvements with regard to blood loss, haemoglobin and shorter length of stay in the LSCP group compared with the ASCP group.

CONCLUSION

This fully powered randomised controlled trial comparing open and laparoscopic sacrocolpopexy has shown clinical equivalence.

Serotype prevalence in adults hospitalised with pneumococcal non-invasive community-acquired pneumonia

BACKGROUND

The distribution of pneumococcal serotypes implicated in non-invasive community-acquired pneumonia (CAP) in adults is currently unknown.

METHODS

A prospective observational cohort study was conducted over 2 years in a large U.K. teaching hospital trust. Urine samples, in addition to routine blood and sputum samples, were obtained from consecutive adults admitted to the hospital with CAP. Pneumococcal serotype was determined from urine samples using a validated multiplex immunoassay which detects 14 serotypes.

RESULTS

Of 920 patients with CAP, 366 had pneumococcal CAP; 242 had a serotype determined. Thirty-day mortality was 10% for all-cause CAP and 9.6% for pneumococcal CAP. Annual incidence of pneumococcal CAP was 36.5 per 100,000, increasing from 12.1 to 274.1 per 100,000 for ages 16-44 years and ≥85 years, respectively. The most prevalent serotypes were 14, 1, 8, 3 and 19A. Less invasive serotypes were significantly associated with increasing age (OR per increasing age group: 1.5, 95% CI 1.2 to 1.9, p<0.001) and co-morbidity (OR per increasing Charlson index group: 1.4, 95% CI 1.0 to 2.0, p=0.036), and with higher 30-day mortality (OR adjusted for age and co-morbidity: 5.5, 95% CI 1.2 to 25.3, p=0.028) compared with highly invasive serotypes. The proportion of patients in whom serotypes contained within the seven-valent childhood pneumococcal conjugate vaccine was identified increased with age (15.6% for patients aged 16-44 years, 41.0% for patients aged ≥85 years; p<0.05).

CONCLUSIONS

In adult invasive and non-invasive pneumococcal CAP, the most common serotypes implicated were 14, 1, 8, 3 and 19A. Age and co-morbidity were associated with the distribution of serotypes identified.

Molecular typing methods for outbreak detection and surveillance of invasive disease caused by Neisseria meningitidis, Haemophilus influenzae and Streptococcus pneumoniae, a review

Invasive disease caused by the encapsulated bacteria Neisseria meningitidis, Haemophilus influenzae and Streptococcus pneumoniae remains an important cause of morbidity and mortality worldwide, despite the introduction of successful conjugate polysaccharide vaccines that target disease-associated strains. In addition, resistance, or more accurately reduced susceptibility, to therapeutic antibiotics is spreading in populations of these organisms. There is therefore a continuing requirement for the surveillance of vaccine and non-vaccine antigens and antibiotic susceptibilities among isolates from invasive disease, which is only partially met by conventional methods. This need can be met with molecular and especially nucleotide sequence-based typing methods, which are fully developed in the case of N. meningitidis and which could be more widely deployed in clinical laboratories for S. pneumoniae and H. influenzae.

Long term trends introduce a potential bias when evaluating the impact of the pneumococcal conjugate vaccination programme in England and Wales

A pneumococcal conjugate vaccine (PCV7) was introduced into the United Kingdom's childhood immunisation schedule in September 2006. Evaluation of its impact on the incidence of invasive pneumococcal disease (IPD) as assessed by routine reports of laboratory-confirmed cases should take into account possible long-term trends due to factors like changes in case ascertainment. To this end, we compared pre-PCV7 trends in reported IPD incidence in England and Wales identified by blood culture with those for two other bacteraemias, Escherichia coli and non -pyogenic streptococci, for which there has not been any public health intervention. While no trend was detected in the age group 65 years and older, there was an annual increase of 3% and 11% in those aged under five years and between five and 64 years, respectively, which was similar for IPD and the other two pathogens. After PCV7 introduction, a continuing trend was only found for non-pyogenic streptococci in under five year-olds. These trends in the incidence for bacteraemias for which there has been no intervention could suggest that there have been changes in case ascertainment because of increased reporting or blood culturing. Accounting for them will improve the evaluation of the impact of PCV7 on IPD.

Long term trends introduce a potential bias when evaluating the impact of the pneumococcal conjugate vaccination programme in England and Wales

A pneumococcal conjugate vaccine (PCV7) was introduced into the United Kingdom's childhood immunisation schedule in September 2006. Evaluation of its impact on the incidence of invasive pneumococcal disease (IPD) as assessed by routine reports of laboratory-confirmed cases should take into account possible long-term trends due to factors like changes in case ascertainment. To this end, we compared pre-PCV7 trends in reported IPD incidence in England and Wales identified by blood culture with those for two other bacteraemias, Escherichia coli and non -pyogenic streptococci, for which there has not been any public health intervention. While no trend was detected in the age group 65 years and older, there was an annual increase of 3% and 11% in those aged under five years and between five and 64 years, respectively, which was similar for IPD and the other two pathogens. After PCV7 introduction, a continuing trend was only found for non-pyogenic streptococci in under five year-olds. These trends in the incidence for bacteraemias for which there has been no intervention could suggest that there have been changes in case ascertainment because of increased reporting or blood culturing. Accounting for them will improve the evaluation of the impact of PCV7 on IPD.

Carbon monoxide re-breathing during low-flow anaesthesia in infants and children

BACKGROUND

Carbon monoxide (CO) has been detected within anaesthesia breathing systems. One potential source in this setting is exhaled endogenous CO. We hypothesized that CO is re-breathed during low-flow anaesthesia (LFA) in infants and children.

METHODS

Twenty children (age 2 months-7 yr) undergoing general anaesthesia were evaluated in a prospective observation study. LFA was established for 60 min followed by high-flow anaesthesia (HFA) for the next 60 min. Exhaled and inspired CO were measured every 5 min within the breathing circuit. Carboxyhaemoglobin (COHb%) was measured at baseline, at 60 min, after LFA, and at 120 min, after HFA.

RESULTS

CO concentrations increased during LFA. Inspired CO peaked at 14 ppm. During HFA, exhaled CO levels remained constant whereas inspired CO decreased markedly. Exhaled and inspired CO during HFA differed significantly from LFA. The trajectory of change in exhaled and inspired CO was most closely associated with the fresh-gas flow (FGF):minute ventilation ratio. COHb% significantly increased in children <2 yr of age at 60 min after LFA and remained increased.

CONCLUSIONS

LFA increased exhaled and inspired CO and increased COHb% in children <2 yr of age. Thus, LFA resulted in re-breathing of exhaled CO and exposure, especially in the youngest children. Re-breathing exhaled gas during LFA could pose a risk for an acute CO exposure in patients who have elevated COHb and high baseline levels of exhaled CO. If practitioners match or exceed minute ventilation with FGF to avoid LFA, CO re-breathing can be limited.

Host and environmental factors associated with Hib in England, 1998-2002

BACKGROUND

Declining effectiveness of the UK's Hib vaccine programme was observed between 1998 and 2002.

OBJECTIVE

To provide insight into non-vaccine factors contributing to ongoing Hib disease in England after immunisation.

DESIGN

Postal questionnaire study, matched case-control design.

SETTING

Health Protection Agency Centre for Infections, England.

PATIENTS

Cases were children born after 1 January 1993 presenting with confirmed Hib infection in England between the start of 1998 and end of 2002, regardless of vaccination status. Controls were matched by date of birth and region.

MAIN OUTCOME MEASURES

Odds ratios were calculated to assess the impact of host and environmental variables on disease risk.

RESULTS

Increased disease risk was noted among children with frequent antibiotic use (adjusted OR (AOR) (trend) 1.51 (95% CI 1.06 to 2.13); p = 0.02) and from sole-parent households (AOR 2.56 (95% CI 1.24 to 5.29); p = 0.01). These two risk factors were further related to each other, consistent with previously reported associations between infection and social deprivation. In fully immunised children, receipt of all three doses of the primary course as an acellular pertussis-containing combination vaccine (DTaP-Hib) increased the risk of vaccine failure (OR 2.88 (95% CI 0.99 to 8.37), p = 0.01). Day care attendance between 2 and 5 years of age was linked with a dose-dependent reduction in risk (AOR (trend) 0.79 (95% CI 0.66 to 0.93); p = 0.01), possibly because of natural boosting of immunity.

CONCLUSIONS

The association noted between invasive infection and social deprivation in this and other studies is concerning and merits further investigation. The importance of ongoing surveillance of vaccine-preventable diseases to allow nested studies of this kind was reinforced.

Vaginal surgery for pelvic organ prolapse using mesh and a vaginal support device

Objectives

To describe a new surgical procedure for pelvic organ prolapse using mesh and a vaginal support device (VSD) and to report the results of surgery.

Design

A prospective observational study

Setting

Two tertiary referral Urogynaecology practices.

Population

Ninety-five women with International Continence Society pelvic organ prolapse quantification stage 2 or more pelvic organ prolapse who underwent vaginal surgery using mesh augmentation and a VSD.

Methods

Surgery involved a vaginal approach with mesh reinforcement and placement of a VSD for 4 weeks. At 6 and 12 months, women were examined for prolapse recurrence, and visual analogue scales for satisfaction were completed. Women completed quality-of-life (QOL) questionnaires preoperatively and at 6 and 12 months.

Main outcome measures

Objective success of surgery at 6 and 12 months following surgery. Secondary outcomes were subjective success, complications, QOL outcomes and patients’ satisfaction.

Results

Objective success rate was 92 and 85% at 6 and 12 months, respectively. Subjective success rate was 91 and 87% at 6 and 12 months, respectively. New prolapse in nonrepaired compartments accounted for 7 of 12 (58%) failures at 12 months. Two of 4 mesh exposures required surgery. Sexual dysfunction was reported by 58% of sexually active women preoperatively and 23% at 12 months. QOL scores significantly improved at 12 months compared with baseline (P < 0.0001).

Conclusion

Vaginal surgery using mesh and a VSD is an effective procedure for pelvic organ prolapse. However, further studies are required to establish the role of the surgery described in this study.

Please cite this paper as:Carey M, Slack M, Higgs P, Wynn-Williams M, Cornish A. Vaginal surgery for pelvic organ prolapse using mesh and a vaginal support device. BJOG 2008;115:391–397.

The descriptive epidemiology of Streptococcus pneumoniae and Haemophilus influenzae nasopharyngeal carriage in children and adults in Kilifi district, Kenya

BACKGROUND

Transmission and nasopharyngeal colonization are necessary steps en route to invasive pneumococcal or Haemophilus influenzae disease but their patterns vary geographically. In East Africa we do not know how these pathogens are transmitted between population subgroups nor which serotypes circulate commonly.

METHODS

We did 2 cross-sectional nasopharyngeal swab surveys selecting subjects randomly from a population register to estimate prevalence and risk-factors for carriage in 2004. H. influenzae type b vaccine was introduced in 2001.

RESULTS

Of 450 individuals sampled in the dry season, 414 were resampled during the rainy season. Among subjects 0-4, 5-9, and 10-85 years old pneumococcal carriage prevalence was 57%, 41%, and 6.4%, respectively. H. influenzae prevalence was 26%, 24%, and 3.0%, respectively. Prevalence of H. influenzae type b in children <5 years was 1.7%. Significant risk factors for pneumococcal carriage were rainy season (odds ratio [OR]: 1.65), coryza (OR: 2.29), and coculture of noncapsulate H. influenzae (OR: 7.46). Coryza was also a risk factor for H. influenzae carriage (OR: 1.90). Of 128 H. influenzae isolates, 113 were noncapsulate. Among 279 isolates of Streptococcus pneumoniae, 40 serotypes were represented and the distribution of serotypes varied significantly with age; 7-valent vaccine-types, vaccine-related types, and nonvaccine types comprised 47%, 19%, and 34% of strains from children aged <5 years. Among older persons they comprised 25%, 28%, and 47%, respectively (P = 0.005).

CONCLUSIONS

The study shows that pneumococcal carriage is common up to 9 years of age and that the majority of serotypes carried at all ages are not covered specifically by the 7-valent pneumococcal conjugate vaccine.

Molecular epidemiology of Haemophilus influenzae type b causing vaccine failures in the United Kingdom

Haemophilus influenzae type b (Hib) was a major cause of pediatric disease in the United Kingdom prior to the introduction of routine Hib immunization in 1992. An unexpected resurgence of cases of vaccine failure was observed with fully vaccinated children from 1999 onward. We investigated whether Hib isolates causing vaccine failures in the United Kingdom could have undergone a change in their population structure to elude the protective effect of Hib vaccine. Molecular epidemiology studies were carried out with 376 isolates from invasive infections (164 vaccine failures and 212 controls). Genetic variability was higher in controls than in vaccine failures. Of the four major clusters obtained, cluster I comprised 92.2% of the total isolates: 156 vaccine failures (95%) and 193 (91%) controls. Cluster IV was specific for vaccine failures but included only four isolates. The increased number of cases of invasive Hib in fully vaccinated children in the United Kingdom was caused by isolates belonging not to a particular or new genotype but to genotypes already circulating in the prevaccination era, before conjugate Hib vaccines were available.