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Expert Review of Pharmacoeconomics &... Aug 2009With the arrival of new, more expensive vaccines, economic evaluation has become an important tool for assessing the feasibility of introducing a new vaccine into a... (Review)
Review
With the arrival of new, more expensive vaccines, economic evaluation has become an important tool for assessing the feasibility of introducing a new vaccine into a country's routine immunization schedule. Haemophilus influenzae type b (Hib) vaccine has been available since the early 1990s, but uptake of the vaccine was slow in low-income countries until the GAVI Alliance started offering financial support for it. However, at some point, GAVI Alliance-supported countries will have to identify other sources of financing for Hib vaccine, meaning cost-effectiveness evidence will be important to support resource allocation decisions. Several middle-income countries have not yet introduced the vaccine. Thus, the aim of this literature review was to identify and evaluate the published evidence on the cost-effectiveness of the Hib vaccine, with particular emphasis on low- and middle-income countries. It is concluded that there are only few studies available from resource-poor countries and some of these are of low quality.
Topics: Cost-Benefit Analysis; Developing Countries; Economics, Pharmaceutical; Haemophilus Infections; Haemophilus Vaccines; Haemophilus influenzae type b; Humans; Immunization Programs
PubMed: 19670994
DOI: 10.1586/erp.09.38 -
Journal of Periodontology Dec 2007Recent meta-analyses reported a weak association between periodontal disease (PD) on clinical examination and cardiovascular disease (CVD). Systemic bacterial exposure... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Recent meta-analyses reported a weak association between periodontal disease (PD) on clinical examination and cardiovascular disease (CVD). Systemic bacterial exposure from periodontitis, which correlates poorly with the clinical examination, has been proposed as the more biologically pertinent risk factor. The purpose of this study was to review and analyze the association between PD with elevated systemic bacterial exposure and CVD.
METHODS
We searched in the PubMed, Cochrane Controlled Trials Register, EMBASE, and SCOPUS databases for all literature examining PD and CVD. From 10 selected publications, we extracted 12 cohort (N = 5) and cross-sectional (N = 7) studies and included 11 of these in a meta-analysis. With stratified analyses, this resulted in 14 analyses of coronary heart disease (CHD; N = 7), stroke (N = 4), and carotid intima-medial thickening (CIMT; N = 3) as a measure of early atherosclerosis. Systemic bacterial exposure was measured by periodontal bacterial burden (N = 1), periodontitis-specific serology (N = 12), or C-reactive protein (N = 1).
RESULTS
Periodontal disease with elevated markers of systemic bacterial exposure was associated strongly with CHD compared to subjects without PD, with a summary odds ratio of 1.75 (95% confidence interval (CI): 1.32 to 2.34; P <0.001). This group was not associated with CVD events or with stroke but was associated with a significant increase in mean CIMT (0.03 mm; 95% CI: 0.02 to 0.04).
CONCLUSION
Periodontal disease with elevated bacterial exposure is associated with CHD events and early atherogenesis (CIMT), suggesting that the level of systemic bacterial exposure from periodontitis is the biologically pertinent exposure with regard to atherosclerotic risk.
Topics: Aggregatibacter actinomycetemcomitans; Antibodies, Bacterial; Atherosclerosis; Biomarkers; C-Reactive Protein; Cardiovascular Diseases; Carotid Stenosis; Coronary Disease; Humans; Odds Ratio; Periodontitis; Porphyromonas gingivalis; Risk Factors
PubMed: 18052701
DOI: 10.1902/jop.2007.070140 -
The Cochrane Database of Systematic... Apr 2007Haemophilus influenzae (H. influenzae) is an important cause of meningitis and pneumonia in children. Vaccine cost is a significant barrier to use in low income... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Haemophilus influenzae (H. influenzae) is an important cause of meningitis and pneumonia in children. Vaccine cost is a significant barrier to use in low income countries. Determining the size of the effects of the vaccine will enable cost-effectiveness comparisons with competing priorities in low income countries.
OBJECTIVES
1. To determine the effects of conjugate Hib vaccine in preventing Hib disease or death in children under five years of age.2. To determine any variation in effect with type of vaccine, number of doses, age at first dose, in children with known HIV infection, or in high and low income countries.3. To determine any serious adverse outcomes.
SEARCH STRATEGY
We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, Issue 4, 2006); MEDLINE (January 1966 to December 2006); EMBASE (1990 to June 2006) and scanned reference lists and contacting of authors of trial reports. Reports in all languages were considered.
SELECTION CRITERIA
All randomised controlled trials (RCTs) or quasi-RCTs of conjugate H. influenzae type b vaccines compared with placebo or no treatment in children who were followed until at least two years of age.
DATA COLLECTION AND ANALYSIS
Two review authors independently selected eligible studies and extracted data.
MAIN RESULTS
Six studies were included in the review, and four in the meta-analyses. The overall quality of the trials was good. The relative risk for invasive Hib disease was 0.20 (95% confidence interval (CI) 0.07 to 0.54; random-effects model), but there was statistically significant unexplained variation (heterogeneity) in the effects of the four trials in the meta-analysis (P = 0.002). The size of the effects did not appear to differ consistently with different vaccine types, the number of vaccine doses, age at first vaccination or use in high income versus low income countries, but the CIs for the effect estimates were wide. Hib-related mortality data showed a non-significant trend towards benefit (relative risk was 0.29; 95% CI 0.07 to 1.20; random-effects model). The relative risk for all cause mortality in the two trials from which data were available were 1.01 (95% CI 0.38 to 2.67, random-effects model) and 0.97. No serious adverse effects were reported in any of the trials.
AUTHORS' CONCLUSIONS
Hib vaccine is safe and effective. In resource-poor settings, decisions to use the vaccine will depend on its cost, the local burden of Hib disease and competing priorities.
Topics: Developing Countries; Haemophilus Infections; Haemophilus Vaccines; Haemophilus influenzae type b; Humans; Polysaccharides, Bacterial; Randomized Controlled Trials as Topic; Vaccines, Conjugate
PubMed: 17443509
DOI: 10.1002/14651858.CD001729.pub2 -
The Cochrane Database of Systematic... 2003Haemophilus influenzae (H. influenzae) is an important cause of meningitis and pneumonia in children, causing an estimated three million cases of serious disease and... (Review)
Review
BACKGROUND
Haemophilus influenzae (H. influenzae) is an important cause of meningitis and pneumonia in children, causing an estimated three million cases of serious disease and hundreds of thousands of deaths annually worldwide. The introduction of H. influenzae type b (Hib) vaccines into routine immunisation schedules in developed countries has been followed by a rapid decline in disease occurrence, but vaccine cost is a significant barrier to use in developing countries. There is a need to determine the size of the effects of the vaccine, to enable cost-effectiveness comparisons with competing priorities in developing countries.
OBJECTIVES
1. To determine the effects of conjugate Hib vaccine in preventing Hib disease or death in children under five years.2. To determine any serious adverse outcomes.
SEARCH STRATEGY
Searches of the Cochrane Central Register of Controlled Trials (CENTRAL) (issue 1, 2003); MEDLINE (January 1966 to April 2003), EMBASE (1990 to April 2003); and scanning of reference lists and contacting of authors of trial reports. Reports in all languages were considered.
SELECTION CRITERIA
All randomised controlled trials or quasi-randomised trials of conjugate H. influenzae type b vaccines compared with placebo or no treatment in children who were followed until at least two years of age.
DATA COLLECTION AND ANALYSIS
Two investigators independently selected eligible studies and extracted data. Differences were resolved by discussion.
MAIN RESULTS
Five studies were included in the review, and four in meta-analyses. The overall quality of the trials was good. The relative risk for invasive Hib disease was 0.20 (95% confidence interval 0.07 to 0.54; random effects model), but there was statistically significant unexplained variation (heterogeneity) in the effects of the four trials in the meta-analysis (p = 0.002). The size of the effects found in the trials did not appear to differ consistently with different vaccine types, the number of vaccine doses, age at first vaccination or use in developed vs developing countries, but the confidence intervals for the effect estimates were wide.Hib-related mortality data showed a non-significant trend towards benefit (relative risk was 0.29; 95% confidence interval 0.07 to 1.20; random effects model). The relative risk for all cause mortality in the single trial from which data were available was 1.01 (95% confidence interval 0.38 to 2.67, random effects model). No serious adverse effects were reported in any of the trials, involving a total of 257,000 infants.
REVIEWER'S CONCLUSIONS
Hib vaccine is safe and effective. The size of the effect could plausibly be anywhere between a 46% and 93% reduction in Hib invasive disease, before the effect of herd immunity is taken into account. In resource-poor settings, decisions to use the vaccine will depend on its cost, the local burden of Hib disease and competing priorities. Insufficient evidence from randomised controlled trials was identified of the effects of Hib conjugate vaccine on either Hib-specific or on all-cause mortality.
Topics: Bacterial Capsules; Developing Countries; Haemophilus Infections; Haemophilus Vaccines; Haemophilus influenzae type b; Humans; Polysaccharides, Bacterial; Randomized Controlled Trials as Topic; Vaccines, Conjugate
PubMed: 14583937
DOI: 10.1002/14651858.CD001729 -
Journal of Clinical Periodontology 2002The purpose of this study was to determine to what extent the presence or absence of periodontal pathogens can distinguish between subjects with chronic and aggressive... (Review)
Review
OBJECTIVES
The purpose of this study was to determine to what extent the presence or absence of periodontal pathogens can distinguish between subjects with chronic and aggressive periodontitis.
MATERIAL AND METHODS
A systematic review of cross sectional and longitudinal studies providing microbiological data both from patients with chronic periodontitis (ChP) and aggressive periodontitis (AgP) at a subject level. Strict inclusion criteria were applied. The presence or absence of five microorganisms was selected as primary study parameters: Actinobacillus actinomycetemcomitans (AA), Porphyromonas gingivalis (PG), Prevotella intermedia (PI), Bacteroides forsythus (BF), and Campylobacter rectus (CR).
RESULTS
The presence or absence of AA could be evaluated in 11 papers. In seven papers the presence or absence of PG could be analysed. Subject specific data on PI were available from six studies. Two studies could be used regarding the presence or absence of BF, and two regarding CR. Sensitivity and specificity of every microbiological test were individually calculated for each selected study, assuming that the clinical diagnosis of AgP or ChP was the true status the tests attempted to detect. AgP was considered to be the condition of interest and ChP was considered equivalent to 'non-AgP'. Receiver Operator Characteristic (ROC) diagrams were constructed using these data. ROC diagrams indicated the limited discriminatory ability of all of the test parameters to identify subjects with AgP. An additional assessment showed that the highly leukotoxic variant of AA was uniquely associated with patients suffering from aggressive periodontitis. However, in a high proportion of patients diagnosed with AgP the presence of this variant could not be detected.
CONCLUSION
The presence or absence of AA, PG, PI, BF or CR could not discriminate between subjects with AgP from those with ChP.
Topics: Acute Disease; Aggregatibacter actinomycetemcomitans; Bacteroides; Campylobacter; Chronic Disease; Exotoxins; Humans; Periodontitis; Porphyromonas gingivalis; Prevotella intermedia; ROC Curve; Sensitivity and Specificity
PubMed: 12787203
DOI: 10.1034/j.1600-051x.29.s3.1.x -
Microbial Drug Resistance (Larchmont,... 2001Haemophilus influenzae is a relevant cause of morbidity and mortality among children under 5 years of age in the developing world. In Latin America, H. influenzae type b... (Meta-Analysis)
Meta-Analysis
Haemophilus influenzae is a relevant cause of morbidity and mortality among children under 5 years of age in the developing world. In Latin America, H. influenzae type b (Hib) conjugate vaccine and surveillance of H. influenzae antimicrobial susceptibility have been implemented in recent years. We have undertaken a systematic review and a pooled analysis on H. influenzae antimicrobial resistance, including reports of 15 Latin America countries over a 10-year period (1990-2000). We have found that 450 (21.4%) of 2,100 invasive isolates were beta-lactamase producers compared to 145 (14.5%) of 998 isolates of noninvasive isolates (p < 0.05). Ampicillin resistance was detected among 783 (21.9%) of 3,577 invasive isolates compared to 111 (17.2%) of 646 noninvasive strains (p < 0.05). In contrast, 568 (41.9%) of 1,355 noninvasive strains were trimethoprim-sulfamethoxazole (TMP-SMX) resistance against 241 (26.9%) of 897 invasive ones (p < 0.05). Therefore, TMP-SMX resistance was more common in nonsterile fluids than in sterile fluids. Over time, rates of beta-lactamase-producing strains were stable in Brazil and Mexico, whereas rates of TMP-SMX resistance were increasing in Brazil. It is predictable that following the Hib immunization, Latin America countries will be faced with increased nontypeable H. influenzae infection. Although standing by the nontypeable H. influenzae vaccine, in this novel epidemiological scenario of post-Hib vaccination in Latin America settings there is a need to improve H. influenzae resistance monitoring to guide clinicians to choose efficacious antimicrobial therapy.
Topics: Data Interpretation, Statistical; Drug Resistance; Haemophilus Infections; Haemophilus influenzae; Humans; Latin America; Respiratory Tract Infections; Trimethoprim, Sulfamethoxazole Drug Combination; beta-Lactamases
PubMed: 11822780
DOI: 10.1089/10766290152773419