Economic evaluation of pertussis prevention by whole-cell and acellular vaccine in Germany

Economic burden of pertussis in children: A single-center analysis in Hangzhou, China

The "reemergence of pertussis" has elicited international concerns, occurring paradoxically amidst the expansion of immunization programs. This study was aimed to evaluate quantitatively the economic burden and identify the determinants that influence the cost associated with treating pertussis in Chinese children. We evaluated the economic burden by Chinese children diagnosed with pertussis at the Children's Hospital, Zhejiang University School of Medicine in 2022. Direct medical expenses and the utilization of medical resources attributed to pertussis were calculated. A generalized linear regression model was applied to analyze the determinants that were associated with the direct medical expenses among patients. Among the 1110 pertussis patients included in the study, 1060 were outpatients and 50 were inpatients. The average direct medical cost was ¥1878.70(i.e. $279.33). Living in urban areas (OR:1.27, p = .04), complications (OR:1.40, p < .001), hospitalization (OR:10.04, p < .001), and ≥ 3 medical visits (OR:3.71, p < .001) were associated with increased direct medical expenses. Having received four doses of the pertussis vaccine was associated with reduced direct medical expenses (OR:0.81, p = .04). This study underscores a substantial economic burden of pertussis in Hangzhou, with pronounced implications for patients residing in urban areas, experiencing complications, requiring hospitalization, having multiple medical consultations, or lacking comprehensive pertussis vaccination.

[Increasing the efficiency of a mobile EPI strategy using injectable polio vaccine in Africa]

Introduction

In 1980, partners initiated a mobile simplified EPI (Expanded programme on immunization) strategy for immunizing, with mobile teams, rural and urban populations in Western Africa. This strategy delivered EPI vaccines in two sessions: 1) 3-8 month-old children: BCG-Diphteria Tetanus Pertussis + reinforced killed Polio vaccine; 2) 9-15 month-old children: Diphteria Tetanus Pertussis + reinforced killed Polio vaccine, Measles-Yellow Fever. This strategy was compared to WHO-UNICEF extended EPI strategy, but results were never published in the context of a planned rapid polio eradication with oral polio vaccine.

Methods

For comparison with standard WHO-UNICEF extended EPI strategy, using oral polio vaccine in four sessions, all the costs generated by these two strategies in 1988 have been collected in two adjacent zones in Burkina Faso, Western Africa: 203,642 inhabitants for WHO-UNICEF extended EPI strategy (Yako); 109,483 inhabitants for mobile simplified EPI strategy (Gourci). An EPI coverage survey at the end of this year has been done in these two adjacent zones with efficiency (costs per fully immunized child) computed.

Results

In Africa, the simplified mobile EPI strategy using reinforced killed polio vaccine was found two times more efficient (12.71 US$ per fully immunized child) than WHO-UNICEF extended EPI strategy using oral polio vaccine (29.67 US$ per fully immunized child), even if DTP-reinforced killed polio vaccine (0.52 US$ per dose) was more expensive than DTP and oral polio vaccine (0.14 US$ for the combined dose). The missed opportunities uncaught up would have doubled coverage in the WHO-UNICEF extended EPI strategy, versus only a 10% increase with the mobile simplified EPI strategy. The main reason for uncaught up missed opportunities in WHO extended EPI strategy was the absence of requested vaccine delivered by a health agent when attending population at meeting point, due to insufficient cold box volume carried on his moped for transport of vaccine.

Discussion

After 30 years, since 1990, of poliomyelitis eradication in Africa using oral polio vaccine and with non-added costs in this study of polio mass campaigns, these results should be published to review EPI strategy.

Whole-Cell and Acellular Pertussis Vaccine: Reflections on Efficacy

Pertussis is a common respiratory infection caused by the bacterium Bordetella pertussis. Although most cases occur in developing countries, it is considered endemic globally. The World Health Organization estimates there are 20-40 million cases of pertussis annually. Pertussis vaccines played a pivotal role in reducing the burden of pertussis disease as well as infant morbidity and mortality. Although the two forms of pertussis vaccine are effective, each has its advantages and drawbacks. This review aims to review the current knowledge on pertussis vaccines, emphasizing vaccine effectiveness in different populations within a community. Clinical trials have shown favorable vaccine efficacy with acellular pertussis (aP)vaccine. However, observational and population-level studies showed that introducing at least a single dose of whole-cell pertussis (wP) vaccine within the routine immunization schedule is associated with better disease protection and a longer duration of immunity. On the other hand, wP vaccine is more reactogenic and associated with higher adverse events. Therefore, the selection of vaccine should be weighed against the effectiveness, reactogenicity, and cost-effectiveness. Due to its safety profile, aP vaccine can be offered to wider population groups. Booster adolescent and pregnant immunization programs have been implemented globally to control outbreaks and protect vulnerable infants. Due to the variable effectiveness performance of both vaccines, different countries adopted distinctive immunization programs. Determining the right vaccination approach depends on financial consideration, immunization program infrastructure, adverse event monitoring, and pertussis surveillance in the community.

Healthcare Resource Consumption and Cost of Invasive Meningococcal Disease in France: A Study of the National Health Insurance Database

Introduction

Invasive meningococcal disease (IMD) is an uncommon but serious infectious disease. Its economic burden is known to be high but is poorly characterised. The objective of this study was to determine costs, as captured in the healthcare claims database, incurred by all patients hospitalised for IMD in France over a 6-year period.

Methods

This case–control study was performed using the French national public health insurance database (SNDS). Cases comprised all individuals hospitalised with acute IMD in France between 2012 and 2017 inclusive. For each case, three controls were identified, matched for age, gender and region of residence. All healthcare resource consumption by cases and controls during the follow-up period was documented. Costs were analysed for the index hospitalisation in cases, 1 year following the index date and then for 5 years following the index date. Costs were assigned from national tariffs. The analysis was performed from a societal perspective. IMD sequelae were identified from hospital discharge summaries.

Results

A total of 3532 cases and 10,590 controls were evaluated. The mean per capita cost of the index IMD hospitalisation was €11,256, and increased with age and with the presence of sequelae. In the year following the index date, mean per capita direct medical costs were €6564 in cases and €2890 in controls. Annual costs were €4254 in cases without sequelae, €10,799 in cases with one sequela and €20,096 in cases with more than one sequela. In the fifth year of follow-up, mean per capita costs were €2646 in cases and €1478 in controls. The excess cost in cases was principally due to the management of sequelae. Amputation, skin scarring and mental retardation generated per capita costs in excess of €20,000 in the first year and in excess of €10,000 for subsequent years.

Conclusion

The economic burden of IMD in France is high and, over the long-term, is driven by sequelae management.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40121-021-00468-w.

Inclusion of the value of herd immunity in economic evaluations of vaccines. A systematic review of methods used

OBJECTIVE

The objectives of this review were to identify vaccine economic evaluations that include herd immunity and describe the methodological approaches used.

METHODS

We used Kim and Goldie's search strategy from a systematic review (1976-2007) of modelling approaches used in vaccine economic evaluations and additionally searched PubMed/MEDLINE and Embase for 2007-2015. Studies were classified according to modelling approach used. Methods for estimating herd immunity effects were described, in particular for the static models.

RESULTS

We identified 625 economic evaluations of vaccines against human-transmissible diseases from 1976 to 2015. Of these, 172 (28%) included herd immunity. While 4% of studies included herd immunity in 2001, 53% of those published in 2015 did this. Pneumococcal, human papilloma and rotavirus vaccines represented the majority of studies (63%) considering herd immunity. Ninety-five of the 172 studies utilised a static model, 59 applied a dynamic model, eight a hybrid model and ten did not clearly state which method was used. Relatively crude methods and assumptions were used in the majority of the static model studies.

CONCLUSION

The proportion of economic evaluations using a dynamic model has increased in recent years. However, 55% of the included studies used a static model for estimating herd immunity. Values from a static model can only be considered reliable if high quality surveillance data are incorporated into the analysis. Without this, the results are questionable and they should only be included in sensitivity analysis.

Cost-effectiveness analysis of various pertussis vaccination strategies primarily aimed at protecting infants in the Netherlands

BACKGROUND

Pertussis is a highly contagious respiratory disease. Despite a high rate of vaccine coverage through the Dutch national immunization program, the incidence of pertussis remains high in the Netherlands and the risk of infection continues. Because pertussis is most severe in unimmunized infants and infants who have only received some of the recommended doses, new pertussis immunization strategies should be considered to protect this vulnerable population.

OBJECTIVE

This study was designed to estimate the cost-effectiveness of 3 new immunization strategies for possible addition to the current Dutch national immunization program: immunization of the infant at birth, immunization of the parents immediately after birth of the child (cocooning), and maternal immunization during the third trimester of pregnancy.

METHODS

A literature search was performed in the PubMed database for articles published in English, German, and Dutch using the following terms: pertussis, whooping cough, vaccination strategies, maternal immunization, cocooning, at birth, vaccine efficacy, mortality, underreporting, prevalence, incidence, and cost-effectiveness. A decision-tree model was developed for this analysis, and data on pertussis morbidity and costs were collected consistently for different age groups (infants <1 year of age and adults 25 to 34 years of age). The size of the infant cohort was set at 200,000 to approximate previous Dutch birth cohorts. The size of the adult cohort was set at 401,380 parents for the cocooning strategy and 201,380 mothers for the maternal immunization strategy. Health benefits (quality-adjusted life-years [QALYs]) and costs were estimated in both cohorts for each of the 3 immunization strate- gies. Incremental cost-effectiveness ratios were calculated from both a payer's and a societal perspective. The robustness of the results was determined through sensitivity analysis.

RESULTS

In the base-case analysis, cocooning and maternal immunization were found to be effective in reducing the incidence of pertussis among infants (123 and 174 infant cases were expected to be prevented, respectively). Furthermore, cocooning and maternal immunization were estimated to be cost-effective from a payer's perspective (euro4600 [US $6400]/QALY and euro3500 [$4900]/QALY, respectively) and even cost-saving from a societal perspective (savings of up to euro7200 [$10,100] and euro5000 [$7000], respectively). Sensitivity analyses revealed that favorable cost-effectiveness was generally robust. In the sensitivity analysis, the cost-effectiveness of cocooning and maternal immunization was mostly sensitive for changes in assumptions on underreporting (200-fold increase in reported number of symptomatic cases) of pertussis disease and infection. With no underreporting, the ICER was estimated at euro211,900 ($296,700)/QALY for cocooning and euro81,600 ($114,200)/QALY for maternal immunization from a payer's perspective. However, even at much lower levels of underreporting (20- to 30-fold increase in incidence), cost-effectiveness remained favorable. The cost-effectiveness of the third strategy, at-birth immunization, was highly unfavorable (euro329,900 [$461,900]/QALY from a payer's perspective and euro330,100 [$462,100]/ QALY from a societal perspective).

CONCLUSIONS

This study estimated that the addition of cocooning or maternal immunization to the current Dutch national immunization program likely would be cost-effective or even cost-saving. These estimates were mainly due to reduction in the number of cases among parents, which are likely to be mild and therefore would largely remain unreported. Immunization at birth was not a cost-effective strategy. Cocooning was the most expensive intervention to implement; however, it resulted in the highest number of QALYs gained (mainly in adults). Maternal immunization would offer better protection of infants, due to maternally acquired antibodies.

Cocooning: influenza vaccine for parents and caregivers in an urban, pediatric medical home

OBJECTIVE

To determine the acceptance of influenza vaccination by caregivers of children at risk for complications of influenza, if their annual vaccination could be administered by their child's pediatric caregivers during their child's office visit.

RESULTS

During the 2008-2009 influenza season, 474 caregivers were approached, and 336 (70.9%) agreed to participate; 44 were excluded because they had already received their seasonal influenza vaccination, leaving 292 participants. Most were female (80.8%), the child's mother (68.5%), and African American (58.6%). In all, 250 of the 292 participants agreed to receive the influenza vaccine in the pediatrician's office. There were no clinically relevant demographic differences between those who received the vaccine and those who did not. The change in vaccination rate for the group of participants from the previous year was significant (23.7% to 85.6%; P < .001).

CONCLUSION

Caregivers of at-risk pediatric patients are accepting of influenza vaccination from pediatric practitioners while attending their child's pediatric clinic visit.

Cost-effectiveness of adolescent pertussis vaccination for the Netherlands: using an individual-based dynamic model

BACKGROUND

Despite widespread immunization programs, a clear increase in pertussis incidence is apparent in many developed countries during the last decades. Consequently, additional immunization strategies are considered to reduce the burden of disease. The aim of this study is to design an individual-based stochastic dynamic framework to model pertussis transmission in the population in order to predict the epidemiologic and economic consequences of the implementation of universal booster vaccination programs. Using this framework, we estimate the cost-effectiveness of universal adolescent pertussis booster vaccination at the age of 12 years in the Netherlands.

METHODS/PRINCIPAL FINDINGS

We designed a discrete event simulation (DES) model to predict the epidemiological and economic consequences of implementing universal adolescent booster vaccination. We used national age-specific notification data over the period 1996-2000--corrected for underreporting--to calibrate the model assuming a steady state situation. Subsequently, booster vaccination was introduced. Input parameters of the model were derived from literature, national data sources (e.g. costing data, incidence and hospitalization data) and expert opinions. As there is no consensus on the duration of immunity acquired by natural infection, we considered two scenarios for this duration of protection (i.e. 8 and 15 years). In both scenarios, total pertussis incidence decreased as a result of adolescent vaccination. From a societal perspective, the cost-effectiveness was estimated at €4418/QALY (range: 3205-6364 € per QALY) and €6371/QALY (range: 4139-9549 € per QALY) for the 8- and 15-year protection scenarios, respectively. Sensitivity analyses revealed that the outcomes are most sensitive to the quality of life weights used for pertussis disease.

CONCLUSIONS/SIGNIFICANCE

To our knowledge we designed the first individual-based dynamic framework to model pertussis transmission in the population. This study indicates that adolescent pertussis vaccination is likely to be a cost-effective intervention for The Netherlands. The model is suited to investigate further pertussis booster vaccination strategies.

The use of modeling in the economic evaluation of vaccines

As a consequence of the increased role of pharmacoeconomics in policy-making, economic evaluations are performed at more and more early stages in the development of a therapeutic. This implies the development of models to assess the future impact of an intervention and to account for the level of uncertainty in the associated parameters. This also applies for economic evaluations of vaccines, where not only progression of disease and associated costs are important, but the transmission of the causing agent in the target population also has to be modelled. In this review, we provide an overview of the models that have been used in recent publications on the pharmacoeconomics of vaccines and go deeper into some of the methodological issues associated with the use of models in the economic evaluation of vaccines.

Clinical experience with DTPw-HBV and DTPw-HBV/Hib combination vaccines

BACKGROUND

Combined diphtheria-tetanus-whole-cell pertussis (DTPw) vaccines remain the cornerstone of many childhood vaccination programs. Larger DTPw-based combination vaccines facilitate high coverage and protection against other childhood pathogens, such as hepatitis B (HBV) and Haemophilus influenzae type b (Hib). Such vaccines have been available since the mid-1990s (Tritanrix-HBV and Tritanrix-HBV/Hib; GlaxoSmithKline [GSK] Biologicals), demonstrating excellent immunogenicity in various schedules. In order to address growing demand for DTPw-based vaccines, GSK Biologicals have developed the Zilbrix range using a new DTPw antigen source and containing reduced quantities of polyribosylribitol phosphate [PRP].

OBJECTIVE

This article presents clinical trial results for both DTPw-based vaccines.

METHODS

GSK Biologicals provided a comprehensive data package, which was supplemented with a Medline literature search.

CONCLUSION

New antigen sources and reduced PRP will ensure the continued supply of DTPw-based combination vaccines for vital global mass vaccination campaigns.

Recent developments in pertussis

Pertussis causes nearly 300,000 deaths in children every year. Most deaths take place in developing countries, but the infection remains a priority everywhere. Pertussis vaccination protects infants and children against death and admission to hospital, but breakthrough disease in vaccinated people can happen. In high-mortality countries, the challenge is to improve timeliness and coverage of childhood vaccination and surveillance. In regions with low mortality and highest coverage, pertussis is frequently the least well-controlled disease in childhood vaccination programmes. Some countries have reported a rise in pertussis in adolescents, adults, and pre-vaccination infants, but how much these changes are real or a result of improved recognition and surveillance remains uncertain. In response, several countries have introduced adolescent and adult acellular pertussis vaccine boosters. The effect so far is unknown; assessment is impeded by poor data. Uncertainties still persist about key variables needed to model and design vaccination programmes, such as risk of transmission from adults and adolescents to infants. New vaccination strategies under investigation include vaccination of neonates, family members, and pregnant women.

Economics of rotavirus gastroenteritis and vaccination in Europe: what makes sense?

Rotavirus is a major cause of gastroenteritis in children throughout Europe and the world. In addition to causing morbidity and mortality in children, rotavirus gastroenteritis (RVGE) creates a major economic burden on health care systems and families in Europe. The costs of hospital admissions for RVGE and nosocomial infections generate significant medical treatment costs throughout the region. Less information is available on the costs associated with less severe episodes and the costs borne by families, including lost time from work. The availability of rotavirus vaccines presents an effective opportunity to prevent RVGE and these associated economic costs, as well as providing protection to each child and hence benefiting the child's family. The adoption of rotavirus vaccine by health authorities in Europe will require a comparison of the costs and benefits. Economic evaluations that compare the costs of vaccination to the economic benefits of rotavirus vaccination will provide an estimate of its financial impact on health care systems and society. However, to provide a complete picture, economic evaluations of rotavirus vaccines will need to account for both the reduced costs and the reduced morbidity from prevented RVGE. Cost-effectiveness analyses based on quality-adjusted life years (QALYs) provide a systematic approach for assessing vaccination as a health investment, comparing the incremental costs associated with rotavirus vaccination and the reduced morbidity and mortality. QALYs provide a standardized approach for quantifying and comparing reductions in health-related quality of life and premature mortality. Although methodologic limitations exist in applying the QALY approach to childhood vaccines, their use in cost effectiveness analyses allows decision makers to consider the full health benefits of rotavirus and other vaccines.

Clinical and economic effects of pertussis outbreaks

BACKGROUND

The reported incidence of pertussis is increasing, especially among the adolescent population. Current outbreak management strategies include investigating cases, contact follow-up, diagnostic testing, and antibiotic prophylaxis and treatment. The cost of these methods is substantial and can be attributed to the mobilization within public health departments to control the outbreaks.

METHODS

Through an extensive review of the literature, the clinical and economic effects of pertussis outbreaks in various nonhousehold settings are discussed.

RESULTS

The reported incidence of pertussis among adolescents and adults in the United States since the early 1980s continues to rise. The challenges of preventing and controlling pertussis outbreaks involve diagnosing pertussis in a timely, accurate, and standardized fashion and understanding the true burden of disease in different age and socioeconomic groups. The economic effects of pertussis have been demonstrated to be significant to individuals and communities, both locally and globally. Costs associated with pertussis often include diagnostic testing, hospitalization, emergency and/or medical office visits, antibiotic and symptomatic treatment, lost work days, and other reductions in productivity. In outbreak settings, increased surveillance, antibiotic prophylaxis, isolation of infected cases, and enhanced communication and education add to the economic burden of this disease. The potential opportunity to apply the use of pertussis booster vaccination to these populations, particularly among adolescents, likely would reduce the occurrence of pertussis and minimize the clinical and economic repercussions of pertussis outbreaks.

CONCLUSIONS

In the near future, it is anticipated that evaluating the effects of a licensed acellular pertussis booster vaccine in persons > or =10 years of age will become routine in pertussis prevention and outbreak-control activities.

Economic burden of pertussis and the impact of immunization

Although routine use of vaccines has diminished the incidence of pertussis disease, it has not eliminated the pathogen. Epidemiologic data confirm that pertussis remains a significant health problem in all age groups. Disease burden is highest in infants, in whom pertussis disease frequently leads to severe complications and mortality, although it is also a significant health burden in adolescents and adults, in whom the reported incidence of pertussis is increasing. The Global Pertussis Initiative reviewed the literature to find data that express the economic impact of this health burden and to review economic evaluations of pertussis immunization. Although only limited data on the direct and indirect costs of pertussis are available, they suggest that it poses a significant economic burden and indicate that the direct medical costs of pertussis depend on the rate of hospitalization and the severity of complications, and are highest in infants. The indirect costs of pertussis also appear to be considerable, particularly among adults, in whom the disease reduces work productivity, because of either personal illness or child care responsibilities. Several health economic models on the cost effectiveness of childhood immunization strategies have been published, and although constrained by missing data, have generally found childhood immunization strategies to be cost-effective. Economic analyses of adolescent and adult immunization strategies have also been conducted, but the findings of these studies have been inconsistent. The most recent evaluations, using much higher estimates of incidence than reported previously, suggest that immunization of adolescents and specific adult subgroups may be cost-effective. The literature review confirmed that the economic burden of pertussis is substantial, but there are gaps in existing information. In the short term, further economic analyses are required, particularly of adolescent and adult immunization. More importantly, collection of primary epidemiologic and economic data should be undertaken in parallel. Despite the existing gaps in data, further research using the most current data should facilitate decisions on new vaccination strategies by describing conditions for favorable results and quantifying the margin of uncertainty.

Pertussis immunization of adolescents in the United States: an economic evaluation

The incidence of reported pertussis has increased during the past decade and poses a growing health and economic burden in developed countries, despite high rates of primary vaccination. Administration of a booster dose of acellular pertussis vaccine to adolescents may help reduce this burden, not only by reducing infections in vaccinated individuals but also by reducing transmission of Bordetella pertussis to other individuals, particularly infants. An epidemiologic model was created to assess the health and economic impact of implementing a program of routine acellular pertussis immunization in adolescents 11-18 years of age in the United States, considering both the reduction in cases in those vaccinated and among the unvaccinated population (due to herd immunity). Inputs for the base case were defined according to information derived from published literature and were supplemented by estimates provided by members of the Global Pertussis Initiative. Both direct and indirect costs were included (in 2002 US dollars) using U.S. data. Outcomes were evaluated over the lifetime of a cohort of potential adolescent vaccine candidates. Because of uncertainty in many of the inputs, extensive sensitivity analyses were conducted. With 80% vaccination coverage of adolescents and a 20% reduction of other cases because of herd immunity, >68,000 cases and 41 pertussis-related deaths would be avoided in the subsequent 10 years by routine administration of acellular pertussis boosters to a single cohort of adolescents in the United States. This strategy would be cost-effective, incurring from 6000 US dollars to 22,000 US dollars per life-year gained. The level of herd immunity attained and the true incidence of pertussis are critical determinants of cost effectiveness, as is the duration of immunity resulting from immunization. The cost of immunization and the discount rate also play a role. Although there is considerable uncertainty surrounding key inputs, the results indicate that the conditions required for adolescent immunization to be economically warranted are realistic.

New Pertussis Vaccination Strategies beyond Infancy: Recommendations by the Global Pertussis Initiative

BACKGROUND

The Global Pertussis Initiative, an expert scientific forum, was established to address the ongoing problems associated with pertussis disease worldwide.

METHODS

The group analyzed pertussis disease trends, developed recommendations to improve disease control through expanded vaccination strategies, and proposed solutions to barriers to implementation and support of research activities.

RESULTS

Bordetella pertussis infection is endemic and continues to be a serious problem among unvaccinated or incompletely vaccinated infants. In addition, the reported incidence of pertussis disease is increasing in adolescents and adults, who not only experience a considerable health burden themselves but also infect vulnerable infants.

CONCLUSIONS

Current vaccination strategies need to be reinforced. Expanded vaccination should include adding booster doses to existing childhood schedules (preschool or adolescent) and booster doses for those specific adult subgroups that have the highest risk of transmitting B. pertussis infection to infants (i.e., new parents, other contacts of newborns, and health care workers). More epidemiological studies and studies of disease transmission and the cost-effectiveness of vaccination would be valuable, and surveillance, diagnostic improvements, and educational campaigns are needed for implementation. However, as a prelude to universal adult vaccination, immediate universal adolescent vaccination should be instituted in countries in which it is economically feasible.

Pertussis vaccination strategies for neonates—an exploratory cost-effectiveness analysis

Hospitalisation and death from pertussis in highly immunised populations largely occurs before the first vaccination at 2 months. A Markov model was constructed to estimate the costs and health consequences of three strategies to reduce pertussis over the first 6 months of an infant's life. Earlier vaccination (at either birth or 1 month in addition to current practice) or vaccination of the parents soon after birth was compared with the current practice of vaccination at 2, 4 and 6 months. The model was populated using data on the incidence and costs from Australia. Disability-adjusted life-years (DALYs) were used as the primary outcome measure. The cost to the Australian public health system was chosen as the economic perspective, and Monte-Carlo simulations were used to accommodate uncertainties in the variables. Vaccination at birth was estimated to cost (S.D.) an additional A$33.21 (A$1.60) per infant and to reduce cases, deaths and DALYs by 45%. Vaccination at 1 month was estimated to cost an additional A$43.24 (A$8.98) per infant and to reduce morbidity by approximately 25%. Parental vaccination at birth was the most expensive alternative, costing an additional A$73.38 (A$4.98) per infant and reducing pertussis morbidity by 38%. The costs per DALY averted were A$330,175 (A$15,461) A$735,994 (A$147,679) and A$787,504 (A$48,075) for the birth, 1 month and parental vaccination strategies, respectively. Changing the estimated factor by which hospitalisations and deaths are under-reported, and the efficacy of early vaccination, had large effects on results. Parental vaccination at birth was most cost-effective where protection persisted for subsequent children. The birth vaccination strategy appears to offer the greatest potential benefit for one-child families, but the efficacy at birth (and 1 month) needs to be established.

Facilitating the WHO expanded program of immunization: the clinical profile of a combined diphtheria, tetanus, pertussis, hepatitis B and Haemophilus influenzae type b vaccine

BACKGROUND

Vaccines are important weapons in the fight against infectious diseases. The World Health Organization (WHO) Expanded Program on Immunization (EPI) has been extended to include recommendations for hepatitis B and Haemophilus influenzae type b (Hib) vaccinations. The WHO has recommended that combined vaccines be used where possible, to reduce the logistic costs of vaccine delivery. This paper reviews the efficacy, safety and cost-effectiveness of Tritanrix-HB/Hib, the only commercially available combined diphtheria, tetanus, whole cell pertussis, hepatitis B and conjugated Hib vaccine.

METHODS

The immunogenicity and reactogenicity results of five published clinical trials involving Tritanrix-HB/Hib in a variety of immunization schedules and countries were reviewed. Based on these data and cost-effectiveness studies, an assessment of its suitability for use in national immunization programs was made.

RESULTS

Tritanrix-HB/Hib has shown excellent immunogenicity in clinical trials using a variety of schedules, with no reduced immunogenicity observed for any of the components of the combined vaccine. It has similar reactogenicity to DTPw vaccines alone. Pharmacoeconomic analyses have shown combined DTP-HB/Hib vaccines to be cost-effective compared to separate vaccines.

CONCLUSIONS

Replacement of DTPw vaccination by Tritanrix-HB/Hib can be done without modifying the existing national immunization programs. This should facilitate widespread coverage of hepatitis B and Hib vaccinations and their rapid incorporation into the EPI.

The potential cost-effectiveness of acellular pertussis booster vaccination in England and Wales

A cost-effectiveness analysis of the introduction of acellular pertussis booster doses at either 4 or 15 years of age was performed. A transmission dynamic model was used to predict the level of indirect protection in those too young to be vaccinated. Multivariate sensitivity analyses were performed. In England and Wales there are an estimated 35,000 general practitioner (GP) consultations, 5500 inpatient days, and nine deaths annually attributable to pertussis, despite high levels of coverage for the primary course (approximately 95%). Around 80% of the bed-days and 90% of the deaths occur in those too young to be immunised (< 3 months of age). The introduction of acellular booster doses at 4 years is expected to reduce morbidity and mortality in the younger age groups by 40-100%, and at 15 years by 0-100%. From the perspective of the health care provider, roughly 50% of the simulations result in a cost per life-year gained of less than 10,000 pounds for vaccination at 4 years, the corresponding proportion for vaccination at 15 years being only 35%. Apart from the degree of indirect protection the model was most sensitive to the discount rate, the price of the vaccine, and the mortality rate. Significant uncertainty remains regarding the epidemiology of pertussis and the impact of booster doses. Nevertheless, the introduction of acellular boosters, particularly at 4 years, has the potential to be cost-effective in the UK.

An economic evaluation of universal pertussis vaccination in Italy

An economic evaluation was performed of universal acellular pertussis vaccination in Italy, where until recently the overall coverage of pertussis vaccination was estimated at 50%. Over the last two years coverage seems to have increased rapidly. By means of a mathematical simulation model, the consequences of pertussis vaccination in terms of both health effects and economic costs were calculated for a single birth cohort followed for 6 years. Incremental analyses were performed for each additional 10% increase in coverage from 50-90%. The results indicate that a 50% coverage rate of pertussis vaccination in Italy was not optimal on the basis of cost-effectiveness and cost-benefit considerations. Additional increases in coverage were found to yield extra health gains at modest net costs or even potential net savings to the health care sector. For example, an increase in coverage to 90% would yield direct net savings of US$42 per extra vaccinee in comparison to a situation of 50% coverage. The total net savings for this strategy would be well over US$100 per additional vaccinee. In the sensitivity analysis, the positive relationship between incremental coverage and incremental efficiency remained unchanged.