Economic aspects of a general vaccination against invasive disease caused by Haemophilus influenzae type b (Hib) via the experience of the Children's Hospital La Fe, Valencia, Spain

Conjugate Haemophilus influenzae type b vaccines for sickle cell disease

BACKGROUND

People affected with sickle cell disease (SCD) are at high risk of infection from Haemophilus influenzae type b (Hib). Before the implementation of Haemophilus influenzae type b conjugate vaccination in high-income countries, this was responsible for a high mortality rate in children under five years of age. In African countries, where coverage of this vaccination is still extremely low, Hib remains one of the most common causes of bacteraemias in children with SCD. The increased uptake of this conjugate vaccination may substantially improve the survival of children with SCD. This is an update of a previously published Cochrane Review.

OBJECTIVES

The primary objective was to determine whether Hib conjugate vaccines reduce mortality and morbidity in children and adults with SCD.The secondary objectives were to assess the following in children and adults with SCD: the immunogenicity of Hib conjugate vaccines; the safety of these vaccines; and any variation in effect according to type of vaccine, mode of administration (separately or in combination with other vaccines), number of doses, and age at first dose.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group's Haemoglobinopathies Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. We also searched trial registries (04 July 2018) and contacted relevant pharmaceutical companies to identify unpublished trials.Date of last search of the Cochrane Cystic Fibrosis and Genetic Disorders Group's Haemoglobinoapthies Trials Register: 18 December 2017.

SELECTION CRITERIA

All randomised controlled trials (RCTs) and quasi-RCTs comparing Hib conjugate vaccines with placebo or no treatment, or comparing different types of Hib conjugate vaccines in people with SCD.

DATA COLLECTION AND ANALYSIS

No trials of Hib conjugate vaccines in people with SCD were found.

MAIN RESULTS

There is an absence of evidence from RCTs relating to the subject of this review.

AUTHORS' CONCLUSIONS

There has been a dramatic decrease in the incidence of invasive Hib infections observed in the post-vaccination era in people with SCD living in high-income countries. Therefore, despite the absence of evidence from RCTs, it is expected that Hib conjugate vaccines may be useful in children affected with SCD, especially in African countries where there is a high prevalence of the disease. The implementation of childhood immunisation schedules, including universal Hib conjugate vaccination, may substantially improve the survival of children with SCD living in low-income countries. We currently lack data to evaluate the potential effect of Hib vaccination among unvaccinated adults with SCD. Further research should assess the optimal Hib immunisation schedule in children and adults with SCD.

Conjugate Haemophilus influenzae type b vaccines for sickle cell disease

BACKGROUND

People affected with sickle cell disease are at high risk of infection from Haemophilus influenzae type b. Before the implementation of Haemophilus influenzae type b conjugate vaccination in high-income countries, this was responsible for a high mortality rate in children under five years of age. In African countries, where coverage of this vaccination is still extremely low, Haemophilus influenzae type b remains one of the most common cause of bacteraemias in children with sickle cell disease. The increased uptake of this conjugate vaccination may substantially improve the survival of children with sickle cell disease.

OBJECTIVES

The primary objective was to determine whether Haemophilus influenzae type b conjugate vaccines reduce mortality and morbidity in children and adults with sickle cell disease.The secondary objectives were to assess the following in children and adults with sickle cell disease: the immunogenicity of Haemophilus influenzae type b conjugate vaccines; the safety of these vaccines; and any variation in effect according to type of vaccine, mode of administration (separately or in combination with other vaccines), number of doses, and age at first dose.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group's Haemoglobinopathies Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. We also contacted relevant pharmaceutical companies to identify unpublished trials.Date of last search: 23 November 2015.

SELECTION CRITERIA

All randomised and quasi-randomised controlled trials comparing Haemophilus influenzae type b conjugate vaccines with placebo or no treatment, or comparing different types of Haemophilus influenzae type b conjugate vaccines in people with sickle cell disease.

DATA COLLECTION AND ANALYSIS

No trials of Haemophilus influenzae type b conjugate vaccines in people with sickle cell disease were found.

MAIN RESULTS

There is an absence of evidence from randomised controlled trials relating to the subject of this review.

AUTHORS' CONCLUSIONS

There has been a dramatic decrease in the incidence of invasive Haemophilus influenzae type b infections observed in the post-vaccination era in people with sickle cell disease living in high-income countries. Therefore, despite the absence of evidence from randomised controlled trials, it is expected that Haemophilus influenzae type b conjugate vaccines may be useful in children affected with sickle cell disease, especially in African countries where there is a high prevalence of the disease. The implementation of childhood immunisation schedules, including universal Haemophilus influenzae type b conjugate vaccination, may substantially improve the survival of children with sickle cell disease living in low-income countries. We currently lack data to evaluate the potential effect of Haemophilus influenzae type b vaccination among unvaccinated adults with sickle cell disease. Further research should assess the optimal Hib immunisation schedule in children and adults with sickle cell disease.

Two or three primary dose regime for Haemophilus influenzae type b conjugate vaccine: meta-analysis of randomized controlled trials

Haemophilus influenzae type b (Hib) is an important cause of meningitis and pneumonia in children. Despite the availability of Hib conjugate vaccine, many countries are still to implement it in their immunization schedule. Before introducing the vaccine in routine immunization programs, it is important to know not only the cumulative efficacy but also the efficacy of each vaccine dose. The primary objective of this review is to find whether two primary dose schedule of Hib vaccine is equally efficacious as the standard three primary dose schedule. A highly sensitive online search was run using the terms 'Haemophilus Vaccines' or 'Haemophilus influenzae type b' and 'conjugate vaccine', and Medline (Ovid), PubMed, Embase, CENTRAL and Scopus were explored for prospective randomized controlled studies. Data were extracted in a predesigned proforma and analyzed using RevMan software. Nine randomized studies were included in the analysis. Pooled vaccine efficacy using a fixed effects model against confirmed invasive Hib disease following the 3, 2 and 1 primary dose schedule were 82% [95% confidence interval (CI) 73-87], 79% (95% CI 54-90) and 65% (95% CI 23-84), respectively, and the overall efficacy was 80% (95% CI 72-85). To conclude, we found that Hib conjugate vaccine is highly efficacious and that the two dose regime is as good as the three dose regime. [The protocol was registered with PROSPERO (CRD42013004490)].

WITHDRAWN: Conjugate vaccines for preventing Haemophilus influenzae type B infections

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, 2006, issue 4) which contains the Acute Respiratory Infections Group's specialized register; MEDLINE (January 1966 to December 2006); EMBASE (1990 to June 2006) and scanned reference lists and contacting of authors of trial reports.

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.

Conjugate vaccines for preventing Haemophilus influenzae type B infections

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.

Are economic evaluations of vaccines useful to decision-makers? Case study of Haemophilus influenzae type b vaccines

BACKGROUND

In concert with efforts to increase global provision, economic evaluations of newer and relatively costly vaccines have proliferated in the medical literature. The extent to which existing vaccine evaluations are useful to decision makers is not clear. We conducted a systematic review of published economic evaluations of conjugate Haemophilus influenzae type b (Hib) vaccine, anticipating that their usefulness to past and present decision makers would be limited by the quality of the analyses and by the extent to which the results were transferable to other settings.

METHODS

We systematically identified economic evaluations of conjugate Hib vaccine. We appraised their quality according to a customized checklist and assessed the extent of and reasons for variability of the results.

RESULTS

Quality assessment of the available economic evaluations disclosed a number of shortcomings, including the failure across all models to derive systematic estimates of vaccine efficacy as well as a lack of transparency in the costing of Hib disease treatment. Wide variations in results appeared to be caused primarily by epidemiologic and health system differences between settings and secondarily to methodologic differences between models. The generalizability of model results appeared low.

CONCLUSIONS

There is scope for improving the overall quality of economic evaluations of Hib vaccination. Relevance to decision makers may also be increased by addressing local budget constraints and vaccine price. There is a need to better understand the decision process, particularly at the national level, to ensure the role of future economic evaluations as important decision tools in the implementation of new vaccines.

Impact of universal Haemophilus influenzae type b vaccination starting at 2 months of age in the United States: an economic analysis

OBJECTIVE

To evaluate the economic impact of universal Haemophilus influenzae type b (Hib) vaccination starting at 2 months of age.

METHODS

Decision-tree-based analysis was conducted of a hypothetical US birth cohort of 3 815 469 infants using population-based vaccination coverage and disease incidence data. All costs were estimated from both the direct cost (medical and nonmedical) and societal perspectives. Net present value, cost-effectiveness ratios, and benefit-cost ratios of the US Hib vaccination program were evaluated.

RESULTS

The results of these analyses showed that the universal vaccination program using the Hib conjugate vaccines in the United States in 2000 was cost-saving from both the direct and societal perspectives, with the benefit of the Hib vaccination program (net present value) from the direct cost and societal perspectives of $0.95 billion and $2.09 billion, respectively. Without a Hib vaccination program, the direct and societal costs of Hib invasive cases would be $1.35 billion and $2.58 billion, respectively. The direct and societal costs of the Hib vaccination program were estimated at $0.39 billion and $0.48 billion, respectively. The direct and societal benefit-cost ratios for the Hib vaccination program were 3.4 and 5.4, respectively. Varying the proportion of vaccines purchased and administered in the public versus the private sector and the proportion of combination vaccine versus monovalent vaccine administered did not have much effect on the results.

CONCLUSIONS

Regardless of the perspective (direct cost or societal) and the assumptions used, the benefit-cost ratios of the US vaccination program are >1.0. Potential changes in the program, including use of more or less Hib combination vaccines, would not significantly alter the benefit-cost ratio. The national Hib vaccination program is highly cost beneficial and results in substantial cost savings.

Impact of non-routine vaccination on the incidence of invasive Haemophilus influenzae type b (Hib) disease: experience in the autonomous region of Valencia, Spain

OBJECTIVE

This study assessed the impact of non-routine vaccination against invasive Haemophilus influenzae (Hib)disease before the introduction of universal childhood Hib vaccination.

METHODS

Data were obtained from a prospective surveillance program for invasive bacterial diseases in children <15 years of age that was begun in the Autonomous Region of Valencia on 1 December 1995.

RESULTS

An incidence of 15.5 cases of invasive Hib disease per 100,000 children <5 years of age was reported in the first year of the surveillance program (from 1 December 1995 to 30 November 1996), when Hib vaccination coverage was estimated to be 32.5%. An increase in vaccination coverage to 44% in the second year (1 December 1996 to 30 November 1997) was associated with a reduction in disease incidence to 3.3 cases per 100,000. After the initiation of universal vaccination in December 1998, only two cases were reported. The effectiveness of non-routine vaccination was 71% in 1997.

CONCLUSIONS

These results show that before the introduction of routine childhood Hib vaccination, widespread use of the vaccine can dramatically reduce the occurrence of invasive Hib disease.

Economic evaluation of Haemophilus influenzae type b vaccination in Slovenia

The objective of the present study was to assess the economical impact of invasive Haemophilus influenzae type b infections in Slovenia, where the annual incidence of these infections is 16.4/100000 in children less than 5 years of age, and to compare it with the costs of a vaccination programme. The lifetime costs and benefits were estimated for the annual birth cohort of 18200 children. In the base-case model, the calculated benefit-to-cost ratios were 0.15, 0.98 and 1.38 taking into account 95% of savings in acute care costs, medical costs, and medical and non-medical costs, respectively. From the point of view of the Institute of Health Insurance of Slovenia, who pays all healthcare and vaccination costs, the vaccination programme per annual birth cohort of 18200 children would require an extra 7023 EUR or 0.40 EUR per cohort-child. The savings to society would represent 118410 EUR, indicating the rationale for inclusion of H. influenzae type b vaccination in the routine childhood immunisation programme in Slovenia.

[Research activity on pediatric vaccines in Spain: descriptive analysis of prospective studies published between 1990 and 1998]

OBJECTIVE

To describe the overall characteristics of prospective studies on vaccines in children, performed by Spanish investigators and published between 1990 and 1998.

METHODS

Through a bibliographic research on MEDLINE and EMBASE, 24 prospective studies, performed in Spain, published as original papers, and with objectives directly related to the administration of vaccines to children have been identified. These studies were grouped as: clinical trials (group A), studies performed on established vaccination programmes (group B), and those that could not be included in the above mentioned groups (group C).

RESULTS

5, 9 and 10 studies belonged to groups A, B and C, respectively. More than 12,800 subjects participated in these studies, belonging to both normal population or specific risk groups. In 11 studies, the study population comprised newborns and infants. The vaccines under investigation were: hepatitis B (10 studies), DTPe/Pa (6), MMR (3), flu (2), Hib (1), hepatitis A (1), and meningococcus A and C (1) to address different objectives (in most of them, immunogenicity and/or reactogenicity). Nine had external financial support; 21 were performed by hospital and/or primary care investigators, and 18 in the Vasque Coutry, Madrid or Valencia. 13 publications reported obtaining informed consent, and 8 on the approval of the study protocol by an independent committee. Ten studies were published by international journals.

CONCLUSIONS

This study shows that most of the studies are conducted by clinicians, with vaccines targetted to newborns and infants, with no external financial support, in a small number of autonomous communities, and usually published in Spanish Journals. The submission of this type of studies to a research ethics committee is desirable, something done to a lesser extent than obtaining informed consent.