Instituting a routine varicella vaccination program in Canada: an economic evaluation

Systematic review of economic evaluations of varicella vaccination programmes

OBJECTIVES

This study carried out a systematic literature review of economic evaluations of varicella vaccination programmes from the earliest publication to the present day, including programmes in the workplace and in special risk groups as well as universal childhood vaccination and catch up programmes.

METHODS

Articles published from 1985 until 2022 were sourced from PubMed/Medline, Embase, Web of Science, NHSEED and Econlit. Eligible economic evaluations, which included posters and conference abstracts, were identified by two reviewers who scrutinised each other's selections at both title and abstract and full report stages. The studies are described in terms of their methodological characteristics. Their results are aggregated by type of vaccination programme and the nature of the economic outcome.

RESULTS

A total of 2575 articles were identified of which 79 qualified as economic evaluations. A total of 55 studies focused on universal childhood vaccination, 10 on the workplace and 14 on high risk groups. Twenty-seven studies reported estimates of incremental cost per quality-adjusted life year (QALY) gained, 16 reported benefit-cost ratios, 20 reported cost-effectiveness outcomes in terms of incremental cost per event or life saved and 16 reported cost-cost offset results. Most studies of universal childhood vaccination reported an increase in overall costs to health services, but often a reduction in cost from a societal perspective.

CONCLUSIONS

The evidence surrounding the cost-effectiveness of varicella vaccination programmes remains sparse with contrasting conclusions in some areas. Future research should particularly aim to encompass the impact of universal childhood vaccination programmes on herpes zoster among adults.

What We Know Now: An Economic Evaluation of Chickenpox Vaccination and Dose Timing Using an Agent-Based Model

OBJECTIVES

The value of chickenpox vaccination is still debated in the literature and by jurisdictions worldwide. This uncertainty is reflected in the inconsistent uptake of the vaccine, where some countries offer routine childhood immunization programs, others have targeted programs, and in many the vaccine is only privately available. Even across the countries that have universal funding for the vaccine, there is a diversity of schedules and dosing intervals. Using an agent-based model of chickenpox and shingles, we conducted an economic evaluation of chickenpox vaccination in Alberta, Canada.

METHODS

We compared the cost-effectiveness of 2 common chickenpox vaccination schedules, specifically a long dosing interval (first dose: 12 months; second dose: 4-6 years) and a short dosing interval (first dose: 12 months; second dose: 18 months).

RESULTS

The economic evaluation demonstrated a shorter dosing interval may be marginally preferred, although it consistently led to higher costs from both the societal and healthcare perspectives. We found that chickenpox vaccination would be cost-saving and highly cost-effective from the societal and healthcare perspective, assuming there was no impact on shingles.

CONCLUSION

Chickenpox vaccine was cost-effective when not considering shingles and remained so even if there was a minor increase in shingles following vaccination. However, if chickenpox vaccination did lead to a substantial increase in shingles, then chickenpox vaccination was not cost-effective from the healthcare perspective.

Economic evaluations of vaccines in Canada: a scoping review

BACKGROUND

This study aims to summarise and describe the evolution of published economic evaluations of vaccines in Canada, thereby outlining the current state of this expanding and meaningful research.

METHODS

Using Arksey and O'Malley's scoping review framework we assembled relevant research from both academic and grey literature. Following abstract and full-text review we identified 60 articles to be included in the final analysis.

RESULTS

We found that since 1988 there has been a steady increase in the number of economic evaluations on vaccines in Canada. Many of these studies focus on the more recently licensed vaccines, such as influenza (16.7%), human papillomavirus (15.0%) and pneumococcal disease (15.0%). Since 2010 economic evaluations of vaccines have shown increased adherence to economic evaluation guidelines (OR = 4.6, CI 1.33, 18.7), suggesting there has been improvement in the consistency and transparency of these studies. However, there remains room for improvement, for instance, we found evidence that studies who stated a conflict of interest are more likely to assert the vaccine of interest was cost-effective (OR = 7.4; CI 1.04, 17.8). Furthermore, most reports use static models that do not consider herd immunity, and only a few evaluate vaccines post-implementation (ex-post) and traveller's vaccinations.

CONCLUSION

Researchers should examine identified research gaps and continue to improve standardization and transparency when reporting to ensure economic evaluations of vaccines best meet the needs of policy-makers, other researchers and the public.

Impact of Model, Methodological, and Parameter Uncertainty in the Economic Analysis of Vaccination Programs

Guidelines for economic evaluations insist that the sensitivity of model results to alternative parameter values should be thoroughly explored. However, differences in model construction and analytical choices (such as the choice of a cost-effectiveness or cost-benefit framework) also introduce uncertainty in results, though these are rarely subjected to a thorough sensitivity analysis. In this article, the authors quantify the effect of model, methodological, and parameter uncertainty, taking varicella vaccination as an example. They used 3 different models (a static model, a dynamic model that only looks at the effect of vaccination on varicella, and a dynamic model that also assesses the implications of vaccination for zoster epidemiology) and 2 forms of analysis (cost-benefit and cost-utility). They also varied the discount rate and time frame of analysis. Probabilistic sensitivity analyses were performed to estimate the impact of parameter uncertainty. In their example, model and methodological choice had a profound effect on estimated cost-effectiveness, but parameter uncertainty played a relatively minor role. Under cost-utility analysis, the probabilistic sensitivity analysis suggested that there was a near certainty that vaccination dominates no vaccination, or the other way around, depending on model choice and perspective. Under cost-benefit analysis, vaccination always appeared to be attractive. Thus, the authors clearly show that model and methodological assumptions can have greater impact on results than parameter estimates, although sensitivity analyses are rarely performed on these sources of uncertainty.

Systematic review of models assessing the economic value of routine varicella and herpes zoster vaccination in high-income countries

BACKGROUND

A systematic review was conducted to assess the cost-effectiveness of routine varicella and herpes zoster (HZ) vaccination in high-income countries estimated by modelling studies.

METHODS

A PubMed search was performed to identify relevant studies published before October 2013. Studies were included in the review if they (i) evaluated the cost-effectiveness of routine childhood or adolescent varicella vaccination and/or HZ vaccination targeting the elderly, and if they (ii) reported results for high-income countries.

RESULTS

A total of 38 model-based studies were identified that fulfilled the inclusion criteria. Routine childhood or adolescent varicella vaccination was cost-effective or cost-saving from a payer perspective and always cost-saving from a societal perspective when ignoring its potential impact on HZ incidence due to reduced or absent exogenous boosting. The inclusion of the potential impact of childhood varicella vaccination on HZ led to net quality-adjusted life-year (QALY) losses or incremental cost-effectiveness ratios exceeding commonly accepted thresholds. Additional HZ vaccination could partially mitigate this effect. Studies focusing only on the evaluation of HZ vaccination reported a wide range of results depending on the selected target age-group and the vaccine price, but most found HZ vaccination to be a cost-effective or marginally cost-effective intervention. Cost-effectiveness of HZ vaccination was strongly dependent on the age at vaccination, the price of the vaccine, the assumed duration of protection and the applied cost per QALY threshold.

CONCLUSIONS

While HZ vaccination is mostly considered cost-effective, cost-effectiveness of varicella vaccination primarily depends on the in- or exclusion of exogenous boosting in the model. As a consequence, clarification on the role of exogenous boosting is crucial for decision-making regarding varicella vaccination.

Economic evaluation of Varicella vaccination: results of a systematic review

INTRODUCTION

The aim of the present study is to review the economic burden of varicella disease and the benefit of universal varicella vaccination in different settings pending its implementation in all Italian regions.

MATERIALS AND METHODS

Research was conducted using PubMed, Scopus and ISI databases. Score quality and data extraction were performed for all included studies.

RESULTS

Twenty-three articles met the criteria: 15 cost-effectiveness, 8 cost-benefit and one cost-utility analysis. Varicella vaccination could save the society from €637,762 (infant strategy) to 53 million annually (combined infant and adolescent strategy). The median and the mean quality scores resulted in 91.8% and 85.4% respectively; 11 studies were considered of high quality and 12 of low quality.

DISCUSSION

The studies are favorable to the introduction of universal varicella vaccination in Italy, being cost saving and having a positive impact on morbidity. The quality score of the studies varied greatly: recent analyses were of comparable quality to older studies.

Epidemiological characteristics of varicella from 2000 to 2008 and the impact of nationwide immunization in Taiwan

Background

Varicella has an important impact on public health. Starting in 2004 in Taiwan, nationwide free varicella vaccinations were given to 1-year-old children.

Methods

Our study investigated the epidemiological characteristics of varicella from 2000 to 2008, and assessed the change of varicella epidemiology after the mass varicella immunization. ICD-9-CM codes related to varicella or chickenpox (052, 052.1, 052.2, 052.7, 052.8, 052.9) were analyzed for all young people under 20 years of age through the National Health Insurance database of Taiwan from 2000 to 2008.

Results

Case numbers of varicella or chickenpox significantly declined after the nationwide immunization in 2004. Winter, particularly January, was the epidemic season of varicella. We found a significant post-vaccination decrease in incidence among preschool children, especially 3 to 6 year-old children-- the peak incidence was 66 per thousand for 4 and 5 year-old children before the nationwide immunization (2000 to 2003), and the peak incidence was 23 per thousand for 6 year-old children in 2008 (p < 0.001). Varicella-related hospitalization also significantly decreased in children younger than 6 years after the nationwide immunization.

Conclusion

The varicella annual incidence and varicella-related hospitalization markedly declined in preschool children after nationwide varicella immunization in 2004.

Sixteen years of global experience with the first refrigerator-stable varicella vaccine (Varilrix)

Without vaccination, chickenpox (varicella) will affect almost every person in the world during their lifetime. The burden of disease due to varicella is often unrecognized. Varilrix is a varicella vaccine derived from the Oka strain of varicella virus. The vaccine, as a frozen formulation, was licensed for use in 1984 and was the first commercially available varicella vaccine. It subsequently became the first refrigerator-stable varicella vaccine; its development commenced in 1991 and it has been licensed for use since 1994. Varilrix is indicated for use in high-risk groups, potentially immunocompromised individuals, and healthy subjects in many countries. This article reviews data from extensive worldwide experience with the refrigerator-stable version of the vaccine, including information derived from its use in over 10,000 individuals participating in clinical trials investigating its immunogenicity, efficacy, effectiveness, and safety, as well as postmarketing data including its use in universal mass vaccination programs. Sixteen years of clinical and postmarketing experience with the same formulation represents the longest and most extensive experience with a refrigerator-stable varicella vaccine worldwide. Varilrix, in conjunction with the trivalent measles-mumps-rubella vaccine Priorix, has also been the basis for clinical development of the tetravalent measles-mumps-rubella-varicella vaccine (Priorix-Tetra).

Impact of methodology on the results of economic evaluations of varicella vaccination programs: is it important for decision-making?

This study aims to review the literature on economic evaluation of childhood varicella vaccination programs and to discuss how heterogeneity in methodological aspects and estimation of parameters can affect the studies' results. After applying the inclusion criteria, 27 studies published from 1980 to 2008 were analyzed in relation to methodological differences. There was great heterogeneity in the perspective adopted, evaluation of indirect costs, type of model used, modeling of the effect on herpes zoster, and estimation of vaccine price and efficacy parameters. The factor with the greatest impact on results was the inclusion of indirect costs, followed by the perspective adopted and vaccine price. The choice of a particular methodological aspect or parameter affected the studies' results and conclusions. It is essential that authors present these choices transparently so that users of economic evaluations understand the implications of such choices and the direction in which the results of the analysis were conducted.

Cost-effectiveness of varicella vaccination programs: an update of the literature

Varicella is one of the most common infectious diseases in childhood, caused by the varicella zoster virus. Although vaccines are available, there are only a few countries with an early-childhood vaccination program. Most countries mainly focus on vaccination of high-risk groups, such as susceptible healthcare workers. One of the main concerns with a routine early-childhood vaccination program is a potential (temporal) increase of the incidence of herpes zoster among elderly adults. In this review, we focus on the cost-effectiveness of varicella vaccination and on the methodology used in the health-economic studies. In particular, we focus on the perspective adopted, type of model used, the modeled effect on herpes zoster, the vaccine efficacy and price, and on the value of time lost by infection. The vast majority of studies show vaccination of high-risk groups - including susceptible adolescents - to be cost saving. Routine early-childhood vaccination programs are always cost saving if indirect costs of production losses are included, or cost effective, as long as the potential negative effects on zoster are not taken into account. We note that most studies included in the review used old vaccine prices and a single dose of the varicella vaccine, whereas multiple doses are now becoming the standard. Despite that, those aspects limit the timeliness of our review and we believe that the current work does provide useful insights in the cost-effectiveness of varicella vaccination.

Economic evaluation of varicella vaccination in Spain: results from a dynamic model

Varicella is a universal childhood disease in Spain, causing approximately 400,000 cases, 1,500 hospitalizations and 15 deaths every year. The aim of this study is to determine the economic impact of childhood varicella vaccination on the burden of disease and associated costs by using a dynamic model. The analysis is based on the varicella transmission model developed by Halloran and adapted to the Spanish context. Cost data (Euro, 2004) were derived from previous studies and official tariffs. Two vaccination scenarios were analysed: (1) routine vaccination program for children aged 1-2 years, and (2) routine vaccination program for children aged 1-2 years completed by a catch-up program during the first year of vaccine marketing for children aged 2-11 years. The analysis considers that a similar coverage rate to the MMR one would be achieved (97.15%). A societal perspective, including direct and indirect costs, and a health care payor perspective were adopted. A probabilistic sensitivity analysis was performed. A routine vaccination program has a positive impact on varicella-related morbidity: the number of varicella cases is estimated to be reduced by 89%, and 1230 hospitalizations are prevented. From the societal perspective, scenario (1) is cost-saving whether or not indirect costs are considered (-51 and -4%, respectively). From the Health Care System the strategy is cost-effective, with a cost-effectiveness ratio estimated at 3,982 Euro per life-year gained, although it leads to a small increase in the costs. Considering the impact of vaccination on morbidity and costs, a routine childhood vaccination program against varicella is worth while in Spain without taking into account the potential impact on HZ.

An analytical framework for immunization programs in Canada

Recent years have seen an increase in the number of new vaccines available on the Canadian market, and increasing divergence in provincial and territorial immunization programs as jurisdictions must choose among available health interventions with limited funding. We present an analytical framework, which we have developed to assist in the analysis and comparison of potential immunization programs. The framework includes 58 criteria classified into 13 categories, including the burden of disease, vaccine characteristics and immunization strategy, cost-effectiveness, acceptability, feasibility, and evaluability of program, research questions, equity, ethical, legal and political considerations. To date this framework has been utilized in a variety of different contexts, such as to structure expert presentations and reports and to examine the degree of consensus and divergence among experts, and to establish priorities. It can be transformed for a variety of other uses such as educating health professionals and the general public about immunization.

Cost-benefit analysis of universal varicella vaccination in the U.S. taking into account the closely related herpes-zoster epidemiology

Many models concur that universal varicella vaccination of children is beneficial from the perspective of reducing societal costs. Yet, the majority of such cost analyses have been modeled under the assumption that varicella vaccination has no adverse effect on the closely related herpes-zoster (HZ) epidemiology. Historical models have assumed that asymptomatic endogenous reactivation is the chief mechanism of boosting that suppresses the reactivation of HZ and that immunity wanes due to the aging process. Recent studies suggest instead that periodic exogenous exposures to wild-type varicella are the predominant factor influencing the curve of increasing HZ incidence rate with advancing age among individuals <50, after which an age-related decline dominates in the elderly. Based on a realistic age-structured model, we compare differences in outcomes of the number of HZ cases and direct medical costs associated with the population existing in 2000 and as it ages (according to the mortality given in the 2000 U.S. census) during the following 50 years with and without implementation of universal varicella vaccination. Under universal varicella vaccination, we assume that 15 years post-licensure, the boosting mechanism known as asymptomatic endogenous reactivation principally serves to limit HZ incidence to 550 per 100,000 person-years in unvaccinated individuals <50 with a previous history of natural varicella--since there has been a vaccine-induced decline in exogenous boosting. We estimate universal varicella vaccination has the impact of an additional 14.6 million (42%) HZ cases among adults aged <50 years during a 50 year time span at a substantial cost burden of 4.1 billion US dollars or 80 million US dollars annually utilizing an estimated mean healthcare provider cost of 280 US dollars per HZ case.

The economic value of childhood varicella vaccination in France and Germany

OBJECTIVE

To determine the economic impact of childhood varicella vaccination in France and Germany.

METHODS

A common methodology based on the use of a varicella transmission model was used for the two countries. Cost data (2002 per thousand) were derived from two previous studies. The analysis focused on a routine vaccination program for which three different coverage rates (CRs) were considered (90%, 70%, and 45%). Catch-up strategies were also analyzed. A societal perspective including both direct and indirect costs and a third-party payer perspective were considered (Social Security in France and Sickness Funds in Germany).

RESULTS

A routine vaccination program has a clear positive impact on varicella-related morbidity in both countries. With a 90% CR, the number of varicella-related deaths was reduced by 87% in Germany and by 84% in France. In addition, with a CR of 90%, routine varicella vaccination induces savings in both countries from both societal (Germany 61%, France 60%) and third-party payer perspectives (Germany 51%, France 6.7%). For lower CRs, routine vaccination remains cost saving from a third-party payer perspective in Germany but not in France, where it is nevertheless cost-effective (cost per life-year gained of 6521 per thousand in the base case with a 45% CR).

CONCLUSION

Considering the impact of vaccination on varicella morbidity and costs, a routine varicella vaccination program appears to be cost saving in Germany and France from both a societal and a third-party payer perspective. For France, routine varicella vaccination remains cost-effective in worst cases when a third-party payer perspective is adopted. Catch-up programs provide additional savings.

The burden and cost of hospitalised varicella and zoster in Australian children

BACKGROUND

Economic analyses of varicella-zoster virus (VZV) immunisation are sensitive to the costs of hospitalised cases, so there is a need to validate VZV hospitalisation data.

AIMS

To assess the accuracy of hospital VZV coding data and to apply these parameters to a population-based sample to estimate incidence and costs.

METHODS

A 3-year retrospective chart review from one hospital to document clinical features and validate coding data. A separate 9-year analysis of discharge data from two hospitals draining a defined region of suburban Melbourne, with adjustment for miscoding and estimates of direct hospital costs.

RESULTS

After correction for miscoding, 224 patients were admitted to one hospital over 3 years, 79% with varicella and 21% with zoster. Miscoding resulted in a 15% underestimate of zoster cases and a 4% overestimate of varicella cases. Thirty-six percent of varicella admissions compared to 80% of zoster admissions were immunocompromised and/or had chronic disease. Compared to otherwise-healthy patients, immunocompromised patients were admitted earlier in their illness and had lower complication rates. Forty-two percent of immunocompromised/chronic disease patients with varicella had a known exposure, usually from a family member. The incidence of hospitalised varicella and zoster in under 15-year olds was 15.7 and 1.8 per 100,000 per year, respectively. This suggests that there are 615 varicella hospitalisations and 72 zoster hospitalisations in this age group each year in Australia, at a total direct cost of over 2.2 million AU dollars.

CONCLUSION

These results highlight the considerable burden of hospitalised zoster and the importance of immunising non-immune contacts of immunocompromised individuals. They also support previous estimates of the incidence of hospitalised varicella in Australian children and adolescents, although direct medical costs may be higher than those previously estimated.

An economic evaluation of varicella vaccination in Italian adolescents

An economic evaluation was performed to assess five varicella vaccination scenarios targeted to 11-year-old Italian adolescents. The scenarios were: "compulsory vaccination" of all adolescents, recommended vaccination of susceptible adolescents on the basis of an "anamnestic screening", a "blood test" or a combination of both ("both tests") and vaccination of adolescents in the private sector, at the parents' charge ("private vaccination"). Probabilities and unit costs were taken from published sources and experts opinion. The accuracy of the anamnestic screening (81.6% sensitivity and 87.3% specificity) was derived from a separate descriptive study among 344 Italian adolescents. The costs and benefits of each scenario were simulated using a Markov model and cost-effectiveness, budget-impact and cost-benefit analyses were conducted. Of all considered scenarios, "both tests" and "anamnestic screening" were the most appealing options with an estimated net direct cost of 5058 and 8929 per life-year gained (compared to no vaccination) versus 14,693-42,842 for the other scenarios. These two scenarios further resulted in substantial net savings for society (over 600,000 per cohort, BCR: 2.17). The need for a serological confirmation was highly dependent on the sensitivity of the anamnestic screening, which is believed to increase once such a program is launched. For practical considerations, "anamnestic screening" seems to be the most convenient option.

The societal value of universal childhood vaccination

Availability of new vaccines preventing infectious diseases in healthy children populations is increasing worldwide. In Canada, despite the current recommendation of the National Advisory Committee on Immunization to include recent vaccines in routine schedule, only a few provinces have incorporated some of the newer vaccines in routine vaccination programs. A review was undertaken of economic evaluations of childhood vaccination strategies performed from the societal point of view in industrialized countries, to gain perspective on their global benefits. The general trend supports most universal vaccination programs as cost-saving or cost-effective for society. Comparison of vaccination programs with other health care interventions indicates that vaccines are often one of society's best healthcare investments. Current data suggest that the Canadian society would benefit from a more complete immunization program.

Cost-effectiveness of immunization strategies for the control of serogroup C meningococcal disease

This study compares the cost-effectiveness of a control strategy for serogroup C meningococcal disease (CMD) relying on surveillance and implementation of a mass immunization campaign effective 1 year after the beginning of an epidemic with strategies based on routine immunization, using either three doses of serogroup C conjugate vaccine given in early infancy or one dose at 1 year of age. The simulation model is based on 25 birth cohorts followed up to age 24 years, and seven epidemiological scenarios including low and high level endemicity, and one to five epidemics over a 49-year period. Epidemiological and cost data were mainly collected in the province of Quebec, Canada. Results indicate that the most effective strategy is a three-dose routine program, with the least effective strategy being mass immunization. A one-dose routine program is the most cost-effective strategy in most likely scenarios. In a societal perspective with a vaccine purchase price of CDN$ 50 per dose, the average incremental cost of the one-dose strategy would be $ 190,000 per case averted, US$ 23,000 per life-year gained, and US$ 42,000 per QALY gained. If vaccine-induced immunity is waning rapidly, mass immunization or routine vaccination with booster dose(s) would be the best control options.

Varicella vaccination in Italy : an economic evaluation of different scenarios

AIM

To determine the economic impact (cost-benefit analysis) of childhood varicella vaccination, with the Oka/Merck varicella zoster virus vaccine live (Varivax) in Italy.

METHODS

This analysis is based on an epidemiological model of varicella zoster virus (VZV) dynamics adapted to the Italian situation. Cost data (Euro, 2002 values) were collected through a literature review. Several vaccination scenarios were analysed: (i) routine vaccination programme for children aged 1-2 years with different levels of vaccination coverage (90%, 70% and 45%) without any catch-up programme; (ii) routine vaccination programme for children aged 1-2 years with different levels of vaccination coverage (90%, 70% and 45%) completed by a catch-up programme for 6-year-old children over the first 5 years of vaccine marketing; and (iii) routine vaccination programme for children aged 1-2 years with different levels of vaccination coverage (90%, 70% and 45%) completed by a catch-up programme during the first year of vaccine marketing for children aged 2-11 years.

PERSPECTIVES

A societal perspective, including both direct and indirect costs, and a health-system perspective, limited to costs supported by Italian Health Authorities, were considered.

RESULTS

A routine vaccination programme has a clearly positive impact on chickenpox morbidity. Respectively, 68% and 57% of chickenpox-related hospitalisations and deaths could be prevented with a 90% coverage rate. With vaccination costs being more than offset by a reduction in chickenpox treatment costs in the base case, such a programme could also induce savings from both a societal and a health-system perspective (40% and 12% savings, respectively for a 90% coverage rate). A lower coverage rate reduces cost savings, but there is still a 9% decrease in overall societal costs for a 45% coverage rate. Although the reduction in total societal costs was robust to the sensitivity analyses performed, a slight uncertainty remains regarding cost reduction from a health-system perspective. However, in this latter perspective, even in the worst-case scenario of the sensitivity analysis, routine vaccination programmes may be cost effective, the worst-case scenario for cost parameters leading to cost per life-year gained of Euro2853. Catch-up programmes combined with routine vaccination should lead to further cost reductions from a societal perspective: 15% for a massive catch-up during the first year of vaccine marketing compared with toddlers' vaccination alone, and 11% for a catch-up focused on 6-year-old children for a period of 5 years. However, the impact of catch-up programmes on the costs from an Italian health-system perspective remains close to zero (+/-1%).

CONCLUSION

This model suggests, with its underlying assumptions and data, that routine ZVZ vaccination may be cost saving from both a societal and a health system perspective in the base case. In the worst-case scenario of the sensitivity analysis, vaccination remains cost effective.

Economic impact of healthcare-associated rotavirus infection in a paediatric hospital

The aim of this prospective study was to determine the extra-length of stay and the average cost for rotavirus healthcare-associated infection (HAI). Children admitted to the paediatric ward of the Reims University Hospital between the 1 December 2001 and 31 March 2002, were included in a pairwise matched (1:1) case-control study. Cases were defined as patients with rotavirus HAI. Controls were selected according to matching variables in a stepwise fashion. The costs measured in this study included all expenses sustained by the hospital. Information on costs was obtained from medical records and the hospital economic department. The attack rate and the incidence of healthcare-associated acquired rotavirus infection were 6.6% and 15.8 per 1000 hospital days, respectively, during a winter outbreak. Fifteen percent of HAI were identified after discharge. The average cost per case was 1930 and the mean excess length of stay was 4.9 days. Our findings clearly demonstrate the substantial expense incurred as a result of HAI caused by rotavirus in children. To prevent these costly infections, several cost-effective measures such as standard precautions should be reinforced in the education of the healthcare workers.

Economic evaluations of varicella vaccination programmes: a review of the literature

Chickenpox infections are generally mild but due to their very high incidence among healthy children they give rise to considerable morbidity and occasional mortality. With the development of a varicella vaccine in the early 1970s and its progressive licensing in many countries, interest in the efficiency of varicella immunisation programmes grew. The objective of this review was to discuss the methodological aspects and results of published economic evaluations of varicella vaccination. From this, we attempted to make recommendations. A computerised search was carried out; 17 full economic evaluations of varicella vaccination were retrieved. The review identified the methodological divergences and similarities between the articles in four areas: study design, epidemiological data, economic data and model characteristics. We assessed to what extent the applied methods conform to general guidelines for the economic evaluation of healthcare interventions and compared the studies' results. The desirability of a universal vaccination programme depends on whose perspective is taken. Despite variability in data and model assumptions, the studies suggest that universal vaccination of infants is attractive to society because large savings occur from averted unproductive days for parents. For the healthcare payer, universal vaccination of infants does not generate savings. Vaccination of susceptible adolescents has been proposed by some authors as a viable alternative; the attractiveness of this is highly dependent on the negative predictive value of anamnestic screening. Targeted vaccination of healthcare workers and immunocompromised individuals appears relatively cost effective. Findings for other target groups are either contradictory or provide insufficient evidence for any unequivocal recommendations to be made. High sensitivity to vaccine price was reported in most studies. This review highlights that some aspects of these studies need to be further improved before final recommendations can be made. First, more transparency, completeness and compliance to general methodological guidelines are required. Second, because of the increasing severity of varicella with age, it is preferable and in some cases essential to use dynamic models for the assessment of universal vaccination strategies. Third, most studies focused on the strategy of vaccinating children only while their results depended heavily on disputable assumptions (regarding vaccine effectiveness and impact on herpes zoster). Since violation of these assumptions could have important adverse public health effects, we suggest pre-adolescent vaccination as a more secure alternative. This option deserves more attention in future analyses.