Rotavirus vaccination for Hong Kong children: an economic evaluation from the Hong Kong Government perspective

Economic evaluation of the introduction of rotavirus vaccine in Hong Kong

BACKGROUND

Rotavirus is a common cause of severe gastroenteritis in young children in Hong Kong (HK) with a high economic burden. This study aimed to evaluate the cost-effectiveness of introducing rotavirus vaccination into the HK Government's Childhood Immunisation Programme (CIP) and to include the potential protective effect of the vaccine against seizures.

METHODS

A decision-support model was customised to estimate the potential impact, cost-effectiveness and benefit-risk of rotavirus vaccination in children below 5 years over the period 2020-2029 in HK. Two doses of Rotarix® and three doses of RotaTeq® were each compared to no vaccination. Rotavirus treatment costs were calculated from a governmental health sector perspective (i.e., costs of public sector treatment) and an overall health sector perspective (both governmental and patient, i.e., costs of public sector treatment, private sector treatment, transport and diapers). We ran probabilistic and deterministic uncertainty analyses.

RESULTS

Introduction of rotavirus vaccination in HK could prevent 49,000 (95% uncertainty interval: ~44,000-54,000) hospitalisations of rotavirus gastroenteritis and seizures and result in ~50 (95% uncertainty interval: ~25-85) intussusception hospitalisations, over the period 2020-2029 (a benefit-risk ratio of ~1000:1), compared to a scenario with no public or private sector vaccine use. The discounted vaccination cost would be US$51-57 million over the period 2020-2029 based on per-course prices of US$72 (Rotarix®) or US$78 (RotaTeq®), but this would be offset by discounted treatment cost savings of US$70 million (government) and US$127 million (governmental and patient health sector). There was a greater than 94% probability that the vaccine could be cost-saving irrespective of the vaccine product or perspective considered. All deterministic 'what-if' scenarios were cost-saving from an overall health sector perspective (governmental and patient).

CONCLUSIONS

Rotavirus vaccination is likely to be cost-saving and have a favourable benefit-risk profile in HK. Based on the assumptions made, our analysis supports its introduction into CIP.

Economic Evaluation of Human Rotavirus Vaccine in Thailand

INTRODUCTION

Rotavirus gastroenteritis is the leading cause of severe diarrhoea among young children < 5 years old. Previous cost-effectiveness analyses on rotavirus (RV) vaccination in Thailand have generated conflicting results. The aim of this current study is to evaluate the economic impact of introducing RV vaccination in Thailand, using updated Thai epidemiological and cost data.

METHODS

Both cost-utility analysis (CUA) and budget impact analysis (BIA) of human rotavirus vaccine (HRV) under a universal mass vaccination (UMV) programme were conducted. A published static, deterministic, cross-sectional population model was adapted to assess costs and health outcomes associated with RV vaccination among Thai children < 5 years old during 1 year for CUA and over a 5-year period (2019-2023) for BIA. Data identified through literature review were incorporated into the model after consultation with local experts. Base case CUA was conducted from a societal perspective with quality-adjusted life year (QALY) discounted at 3% annually. Scenario analyses as well as one-way and probabilistic sensitivity analyses were conducted to assess the robustness of the base case CUA results. Costs were updated to 2017.

RESULTS

At 99% coverage, HRV vaccination would substantially reduce RV-related disease burden. With an incremental cost-effectiveness ratio (ICER) of Thai baht (THB) 49,923/QALY gained, HRV vaccination versus no vaccination was cost-effective when assessed against a local threshold of THB 160,000/QALY gained. Scenario and sensitivity analyses confirmed the cost-effectiveness with all resultant ICERs falling below the willingness-to-pay threshold. HRV use in the UMV programme was estimated to result in a net expenditure of about THB 255-281 million to the Thai government in the 5th year of the programme, depending on vaccine uptake.

CONCLUSION

HRV vaccination is estimated to be cost-effective in Thailand. The budget impact following inclusion of HRV into the UMV programme is expected to be partially offset by substantial reductions in RV-related disease costs.

FUNDING

GlaxoSmithKline Biologicals SA GSK STUDY IDENTIFIER: HO-17-18213.

Rotavirus vaccine effectiveness in Hong Kong children

BACKGROUND

Rotavirus is a common infectious cause of childhood hospitalisation in Hong Kong. Rotavirus vaccines have been used in the private sector since licensure in 2006 but have not been incorporated in the government's universal Childhood Immunisation Programme. This study aimed to evaluate rotavirus vaccine effectiveness against hospitalisation.

METHODS

This case-control study was conducted in the 2014/2015 rotavirus season in six public hospitals. Hospitalised acute gastroenteritis patients meeting inclusion criteria were recruited and copies of their immunisation records were collected. Case-patients were defined as enrolled subjects with stool specimens obtained in the first 48h of hospitalisation that tested positive for rotavirus, whereas control-patients were those with stool specimens obtained in the first 48h of hospitalisation testing negative for rotavirus. Vaccine effectiveness for administration of at least one dose of either Rotarix(®) (GlaxoSmithKline Biologicals) or RotaTeq(®) (Merck Research Laboratories) was calculated as 1 minus the odds ratio for rotavirus vaccination history for case-patients versus control-patients.

RESULTS

Among the 525 eligible subjects recruited, immunisation records were seen in 404 (77%) subjects. 31% (162/525 and 126/404) tested positive for rotavirus. In the 404 subjects assessed for vaccine effectiveness, 2.4% and 24% received at least 1 dose of either rotavirus vaccine in case- and control-patients respectively. The unmatched vaccine effectiveness against hospitalisation for administration of at least one dose of either rotavirus vaccines was 92% (95% confidence interval [CI]: 75%, 98%). The matched analyses by age only and both age and admission date showed 96% (95% CI: 72%, 100%) and 89% (95% CI: 51%, 97%) protection against rotavirus hospitalisation respectively.

CONCLUSIONS

Rotavirus vaccine is highly effective in preventing hospitalisation from rotavirus disease in young Hong Kong children.

Systematic review of the economic value of diarrheal vaccines

Diarrheal disease is a leading cause of child mortality in low-income settings and morbidity across a range of settings. A growing number of studies have addressed the economic value of new and emerging vaccines to reduce this threat. We conducted a systematic review to assess the economic value of diarrheal vaccines targeting a range of pathogens in different settings. The majority of studies focused on the economic value of rotavirus vaccines in different settings, with most of these concluding that vaccination would provide significant economic benefits across a range of vaccine prices. There is also evidence of the economic benefits of cholera vaccines in specific contexts. For other potential diarrheal vaccines data are limited and often hypothetical. Across all target pathogens and contexts, the evidence of economic value focuses the short-term health and economic gains. Additional information is needed on the broader social and long-term economic value of diarrhea vaccines.

Rotavirus incidence in hospitalised Hong Kong children: 1 July 1997 to 31 March 2011

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1.6% of hospitalized children below 5 years of age had a primary or any secondary discharge diagnosis of rotavirus.

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Incidence of discharge diagnosis of rotavirus was 1071 and 542/100,000 person-years below 2 and 5 years of age, respectively.

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A discharge diagnosis of rotavirus in children below 5 years of age likely under-reports true incidence by 1.59–2.02 times.

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Adjusted and unadjusted incidence of rotavirus and all-cause gastroenteritis trended up, not down, from 1997 to 2011.

Sentinel laboratory surveillance from one hospital and passive discharge diagnosis (Clinical Management System, CMS) data from all public Hospital Authority (HA) hospitals were used to estimate disease burden and incidence of rotavirus in hospitalised Hong Kong children over 14 rotavirus seasons (1 July 1997 to 31 March 2011). A primary diagnosis of a gastroenteritis-related disorder was noted in 9.8% of children aged below 5 years, and a primary or secondary diagnosis in 11.8%. Any CMS diagnosis of rotavirus (ICD 008.61) was initially used to derive incidence estimates of rotavirus by age group. Rotavirus was recorded as any primary or any secondary diagnosis in 1.6% of children below 5 years of age. The unadjusted incidence rates per 100,000 person-years based on any CMS diagnosis of rotavirus were: 249 (0 to <1m); 612 (1 to <2m); 1066 (2 to <6m); 1383 (6 to <11m); 959 (1 to <2y); 406 (2 to <3y); 233 (3 to <4y); 124 (4 to <5y). Overall the rotavirus incidence was 1071 in children below 2 years and 542 in children below 5 years of age, with the incidence rates trending up during the time period (p = 0.001). A similar but less marked upward trend (p = 0.046) was noted for the incidence of all-cause gastroenteritis. Laboratory results from a single surveillance hospital (1 July 2000 to 31 March 2011) were then linked to these CMS codes to derive adjustment factors for possible over- and under-diagnosis of rotavirus based on CMS codes alone. This analysis suggested that a CMS diagnosis of rotavirus alone likely under-reported true incidence by a factor of between 1.59 and 2.02 in children below 5 years of age. Despite the availability of rotavirus vaccines in the private sector since 2006, no reduction in the incidence of hospitalisation for either rotavirus or all-cause gastroenteritis was noted in Hong Kong children below 5 years of age over 14 rotavirus seasons (1997–2011).

Cost-effectiveness of a pentavalent rotavirus vaccine in Japan

OBJECTIVE

To evaluate the impact of universal vaccination with a pentavalent rotavirus vaccine (RV5) on the healthcare burden and costs associated with rotavirus gastroenteritis (RGE) in Japan.

METHODS

The model included a hypothetical cohort of 1,091,156 children followed for their first 5 years of life. In the absence of universal vaccination, there were 19 deaths, 78,000 hospitalizations, and 678,000 outpatient visits due to RGE. The efficacy of RV5 is based on international clinical trial data, which was similar to the efficacy observed in clinical trials conducted in Japan. The primary outcome measure is the cost per quality-adjusted-life-year (QALY) gained. In the base case, the QALY loss per 1000 RGE episodes included 2.2 for children and 1.8 per parent.

RESULTS

Universal vaccination is projected to reduce hospitalizations by 92%, outpatient visits by 74%, and work-loss days by 73%. For the base case analysis, the total vaccination cost was ¥26 billion. The estimated reduction in medical costs was ¥16 billion. Of 2500 QALYs gained with the vaccination program, approximately half are directly attributed to the child. In the base case analysis, the incremental cost-effectiveness ratio (ICER) for vaccination vs. no vaccination is ¥4 million and ¥2 million per quality-adjusted life year (QALY) gained from the healthcare payer and societal perspectives, respectively. The ICERs are ¥8 million and ¥4 million if parental disutilities are excluded. KEY LIMITATION: The QALY decrements for children and parents were evaluated using different instruments, and the QALY decrements do not vary based on episode severity. Given the interdependence between children and their parents, excluding parental disutilities may under-estimate the impact of RGE.

CONCLUSION

Universal vaccination with RV5 in Japan is projected to have a substantial public health impact and may be cost-effective from both the payer and societal perspectives if parental disutilities are included in the cost-effectiveness ratios.

A critical literature review of health economic evaluations of rotavirus vaccination

Two licensed vaccines are available to prevent RVGE in infants. A worldwide critical review of economic evaluations of these vaccines was conducted. The objective was to describe differences in methodologies, assumptions and inputs and determine the key factors driving differences in conclusions. 68 economic evaluations were reviewed. RV vaccination was found to be cost-effective in developing countries, while conclusions varied between studies in developed countries. Many studies found that vaccination was likely to be cost-effective under some scenarios, such as lower prices scenarios, inclusion of herd protection, and/or adoption of a societal perspective. Other reasons for variability included uncertainty around healthcare visits incidence and lack of consensus on quality of life (QoL) valuation for infants and caregivers. New evidence on the vaccination effectiveness in real-world, new ways of modeling herd protection and assessments of QoL in children could help more precisely define the conditions under which RV vaccination would be cost-effective in developed countries.

Efficacy, safety and immunogenicity of a human rotavirus vaccine (RIX4414) in Hong Kong children up to three years of age: a randomized, controlled trial

BACKGROUND

A phase III, double-blind, randomized, controlled trial was conducted in Hong Kong to evaluate the efficacy, safety and immunogenicity of a human rotavirus vaccine, RIX4414 (Rotarix) against severe rotavirus gastroenteritis in children up to three years of age.

METHODS

Healthy infants aged 6-12 weeks were enrolled between 08-December-2003 and 31-August-2005 and received two oral doses of either RIX4414 vaccine (N=1513) or placebo (N=1512) given 2 months apart. Vaccine efficacy was assessed from two weeks post-Dose 2 until the children were two and three years of age. Anti-rotavirus IgA seroconversion rate was calculated pre-vaccination and 1-2 months post-Dose 2 using ELISA (cut-off=20 U/mL) for 100 infants. Safety was assessed until the children were two years of age; serious adverse events (SAEs) were recorded throughout the study period.

RESULTS

In children aged two and three years of life, vaccine efficacy against severe rotavirus gastroenteritis was 95.6% (95% CI: 73.1%-99.9%) and 96.1% (95% CI: 76.5%-99.9%), respectively. The seroconversion rate 1-2 months after the second dose of RIX4414 was 97.5% (95% CI: 86.8%-99.9%). At least one SAE was recorded in 439 and 477 infants who were administered RIX4414 and placebo, respectively (p-value=0.130). Six intussusception cases were reported (RIX4414=4; placebo=2) and none was assessed to be vaccine-related.

CONCLUSION

RIX4414 was efficacious, immunogenic and safe in the prevention of rotavirus gastroenteritis for at least two years post-vaccination in Hong Kong children.

Cost-effectiveness of rotavirus vaccination in Bolivia from the state perspective

BACKGROUND

In Bolivia, in 2008, the under-five mortality rate is 54 per 1000 live births. Diarrhea causes 15% of these deaths, and 40% of pediatric diarrhea-related hospitalizations are caused by rotavirus illness (RI). Rotavirus vaccination (RV), subsidized by international donors, is expected to reduce morbidity, mortality, and economic burden to the Bolivian state. Estimates of illness and economic burden of RI and their reduction by RV are essential to the Bolivian state's policies on RV program financing. The goal of this report is to estimate the economic burden of RI and the cost-effectiveness of the RV program.

METHODS

To assess treatment costs incurred by the healthcare system, we abstracted medical records from 287 inpatients and 6751 outpatients with acute diarrhea between 2005 and 2006 at 5 sentinel hospitals in 4 geographic regions. RI prevalence rates were estimated from 4 years of national hospital surveillance. We used a decision-analytic model to assess the potential cost-effectiveness of universal RV in Bolivia.

RESULTS

Our model estimates that, in a 5-year birth cohort, Bolivia will incur over US$3 million in direct medical costs due to RI. RV reduces, by at least 60%, outpatient visits, hospitalizations, deaths, and total direct medical costs associated with rotavirus diarrhea. Further, RV was cost-savings below a price of US$3.81 per dose and cost-effective below a price of US$194.10 per dose. Diarrheal mortality and hospitalization inputs were the most important drivers of rotavirus vaccine cost-effectiveness.

DISCUSSION

Our data will guide Bolivia's funding allocation for RV as international subsidies change.

Cost-effectiveness of a pentavalent human-bovine reassortant rotavirus vaccine for children ≤5 years of age in Taiwan

OBJECTIVE

A Markov model was used to assess the impact of RV5, a pentavalent (G1, G2, G3, G4, P1A[8]) human bovine (WC3 strain) reassortant rotavirus vaccine, on reducing the healthcare burden and cost associated with rotavirus gastroenteritis (RGE) in Taiwan. Other cost-effectiveness analyses for rotavirus vaccination in industrialized countries have produced varying results depending on the input parameters assumed.

METHODS

Vaccination with RV5 is compared to no vaccination in a hypothetical cohort of Taiwanese children during their first 5 years of life to determine the per dose prices at which vaccination would be cost neutral or provide good value based on established standards from the healthcare (direct medical care costs only) and societal (all RGE-related costs) perspectives. The effects of vaccination on RGE healthcare utilization and days of parental work loss missed are based on results from the Rotavirus Efficacy and Safety Trial.

RESULTS

Without vaccination there would be 122,526 symptomatic episodes of RGE. Universal vaccination would reduce RGE-related deaths, hospitalizations, emergency department, and outpatient visits by 91.7%, 92.1%, 83.7%, and 73.4%, respectively. The price per dose at which vaccination would be cost-neutral is US$ 21.80 (688 NTD) and US$ 26.20 (827 NTD) from the healthcare and societal perspectives, respectively. At $25 per dose, the cost per QALY gained is US$ 2261 (71,335 NTD) from the healthcare perspective and cost saving from the societal perspective. KEY LIMITATION: The model only assesses the effect of RV5 on vaccinated children and does not account for herd immunity. However, given that high levels of coverage are anticipated in Taiwan, the effects of herd immunity are likely to be short-term.

CONCLUSION

A pentavalent rotavirus vaccination program is likely to substantially reduce the healthcare burden associated with rotavirus gastroenteritis at a cost per QALY ratio within the range defined as cost-effective.

Cost-effectiveness of nationwide hepatitis B catch-up vaccination among children and adolescents in China

Liver disease and liver cancer associated with childhood-acquired chronic hepatitis B are leading causes of death among adults in China. Despite expanded newborn hepatitis B vaccination programs, approximately 20% of children under age 5 years and 40% of children aged 5 to 19 years remain unprotected from hepatitis B. Although immunizing them will be beneficial, no studies have examined the cost-effectiveness of hepatitis B catch-up vaccination in an endemic country like China. We examined the cost-effectiveness of a hypothetical nationwide free hepatitis B catch-up vaccination program in China for unvaccinated children and adolescents aged 1 to 19 years. We used a Markov model for disease progression and infections. Cost variables were based on data published by the Chinese Ministry of Health, peer-reviewed Chinese and English publications, and the GAVI Alliance. We measured costs (2008 U.S. dollars and Chinese renminbi), quality-adjusted life years, and incremental cost-effectiveness from a societal perspective. Our results show that hepatitis B catch-up vaccination for children and adolescents in China is cost-saving across a range of parameters, even for adolescents aged 15 to 19 years old. We estimate that if all 150 million susceptible children under 19 were vaccinated, more than 8 million infections and 65,000 deaths due to hepatitis B would be prevented.

CONCLUSION

The adoption of a nationwide free catch-up hepatitis B vaccination program for unvaccinated children and adolescents in China, in addition to ongoing efforts to improve birth dose and newborn vaccination coverage, will be cost-saving and can generate significant population-wide health benefits. The success of such a program in China could serve as a model for other endemic countries.

Budget impact and cost-effectiveness of including a pentavalent rotavirus vaccine in the New Zealand childhood immunization schedule

OBJECTIVES

To estimate: 1) rotavirus disease burden in New Zealand children aged under 5 years, and 2) health benefits, budget impact, and cost-effectiveness of incorporating a pentavalent rotavirus vaccine (PRV) into the national immunization schedule.

METHODS

A static equilibrium model was developed to evaluate health benefits and budget impact of vaccinating five successive birth cohorts with PRV at $50 per dose and 85% coverage (three doses). Cost-effectiveness was estimated from the societal perspective in year 5 of the program, with future health benefits discounted at 3.5% per annum.

RESULTS

By the age of 5 years, one in five children will have sought medical advice for rotavirus gastroenteritis and one in 43 will have been hospitalized. In 2009, we estimate 1506 hospitalizations (476 per 100,000; 95% confidence interval 451, 502), 3086 Emergency Department (ED) presentations not requiring hospitalization, plus 10,120 cases of rotavirus gastroenteritis managed solely in primary care. The annual societal cost is $7.07 million, including 41% from hospitalization and 25% from caregiver income loss. Health benefits will increase and the cost of illness will decline by 78% in year 5 as successive birth cohorts are immunized. In the fifth year, 1191 hospitalizations, 2442 ED treated cases, 9762 primary care consultations, and 0.8 deaths will be averted. It requires six vaccinated children to avoid one primary care consultation, 49 to avert one hospitalization, and 73,357 to prevent one death. The incremental cost is $2.99 million and the break-even price per vaccine dose is $32.39 at 2006 prices. The cost is $2509 to avert one hospitalization and $305 to prevent one case seeking health-care assistance. The cost per life-year gained in year 5 is $143,097 and the cost per quality-adjusted life-year (QALY) gained is $46,092 (US$26,774). The cost per QALY is sensitive to incidence rates, vaccine price and efficacy, loss of quality of life by the child, case fatality, and caregiver income loss.

CONCLUSIONS

From a societal perspective, addition of PRV to the New Zealand childhood immunization schedule would confer important clinical gains at a modest cost per QALY gained.

Estimating the incidence of symptomatic rotavirus infections: a systematic review and meta-analysis

BACKGROUND

We conducted for the first time a systematic review, including a meta-analysis, of the incidence of symptomatic rotavirus (RV) infections, because (1) it was shown to be an influential factor in estimating the cost-effectiveness of RV vaccination, (2) multiple community-based studies assessed it prospectively, (3) previous studies indicated, inconclusively, it might be similar around the world.

METHODOLOGY

Pubmed (which includes Medline) was searched for surveys assessing prospectively symptomatic (diarrheal) episodes in a general population and situation, which also reported on the number of the episodes being tested RV+ and on the persons and the time period observed. A bias assessment tool was developed and used according to Cochrane guidelines by 4 researchers with different backgrounds. Heterogeneity was explored graphically and by comparing fits of study-homogenous 'fixed effects' and -heterogeneous 'random effects' models. Data were synthesized using these models. Sensitivity analysis for uncertainty regarding data abstraction, bias assessment and included studies was performed.

PRINCIPAL FINDINGS

Variability between the incidences obtained from 20 studies is unlikely to be due to study groups living in different environments (tropical versus temperate climate, slums versus middle-class suburban populations), nor due to the year the study was conducted (from 1967 to 2003). A random effects model was used to incorporate unexplained heterogeneity and resulted in a global incidence estimate of 0.31 [0.19; 0.50] symptomatic RV infections per personyear of observation for children below 2 years of age, and of 0.24 [0.17; 0.34] when excluding the extreme high value of 0.84 reported for Mayan Indians in Guatemala. Apart from the inclusion/exclusion of the latter study, results were robust.

CONCLUSIONS/SIGNIFICANCE

Rather than assumptions based on an ad-hoc selection of one or two studies, these pooled estimates (together with the measure for variability between populations) should be used as an input in future cost-effectiveness analyses of RV vaccination.

Reviewing the cost effectiveness of rotavirus vaccination: the importance of uncertainty in the choice of data sources

Published health economic evaluations of rotavirus vaccination up until July 2008 were reviewed. We assess whether differences in the results and conclusions of the various studies are due to differences in methodological and modelling choices, and/or the way parameter uncertainty was taken into account, or whether these are merely the result of genuine country/region-specific differences. No unambiguous single answer emerged as to whether universal rotavirus vaccination is or is not cost effective. The relevance and merits of each study need to be assessed within its context. This is illustrated by the fact that comparisons of different analyses for a single country show that one of the most important explanations for the variations in results and conclusions seems to be the use of different information sources for the estimation of input parameters. Future studies should gather reliable and relevant information focusing on the most influential input parameters, i.e. rotavirus mortality (and efficacy against rotavirus deaths) for low- and middle-income countries, and a range of variables for high-income countries, including the incidence and cost of rotavirus hospitalization. Moreover, if no information is available for an important input parameter, the impact of a wide range of values should be explored rather than excluding it from the analysis or specifying a single-point value. Furthermore, future analyses may have to consider ways of accounting for herd immunity (e.g. by using a dynamic model).