Cost –effectiveness analysis of a Universal Rotavirus Immunization Program in Japan

Authors: Sato T, Nakagomi T And

Nakagomi O.Article :-Jpn.

Journal of infectious

disease, 64, 277-283,2011

Moderator:Dr. Subodh Gupta

Introduction

• Rotavirus is the major cause of severe dehydrating diarrhea

• Estimated 611,000 deaths annually among under-five in developing countries.

• Two live oral rotavirus vaccines - Rota Teq and Rota Trix licensed in >100 countries

• Incorporated in routine childhood immunization programs of >20 countries.

Objective:

• To evaluate cost-effectiveness analysis of rotavirus vaccination, with view to facilitate the decision of whether rotavirus vaccine should be included in the universal immunization program in Japan.

My learning objective:

• To learn about cost-effectiveness analysis.

Mathematical Modeling:

Becoming an increasingly important subject as computers expand our ability to translate mathematical equations and formulations into concrete conclusions concerning the world, both natural and artificial, that we live in.

Process of mathematical Modeling

Method Mathematical modeling

Using hypothetical 2009 birth cohort of 1.1 million Japanese children

Follow-up model for 5 years.

A Markov model was constructed

The costs and outcomes of vaccination was compared for 2 different scenarios:

- Absence of rotavirus immunization program and

- Implementation of a universal rotavirus immunization program

Cost-effectiveness analysis

Interpretation and explanation of the result

Cont…

• The model evaluated the potential impact of rotavirus vaccination on – direct medical costs– indirect costs– quality of life (for hospitalization and outpatient visits)

• The immunization program was evaluated - From a societal perspective and

- The Health perspective.

Assumptions

• The complete course of Rotarix (2 doses) or RotaTeq (3 doses) would be administered concomitantly with other vaccines to all children at 0–5 months of age.

• The same efficacy levels were assumed for both vaccines

• Vaccine efficacy – Hospitalizations - 95%– Outpatients Visits - 85%

• Vaccination cost of ¥ 20,000 per course was assumed for both vaccines (based on CDC price list including cost of administration)

Assumptions (cont…)Direct medical cost

– outpatient visit - ¥ 13,830

– Hospitalization - ¥ 138,298

Indirect medical cost• Productivity loss (number of days)

– Outpatient visit – 2 days– Hospitalization – 5 days

• Productivity loss per day– Hospitalization - ¥ 38,544 per caregiver – Outpatient visit - ¥ 15,418 per caregiver

Annual discount rate - 5%

Measure of benefit:

• The benefit measure was the number of quality-adjusted life-years (QALYs).

• Program was considered cost-effective if the ICER was less than ¥ 6 million per QALY gained.

Analysis of uncertainty:

• One-way sensitivity analyses were performed to examine the effects of changes in following variables on the base results.

The direct medical cost and the productivity loss per case (±25%from the base case),

The utility (95% confidence interval) , The vaccine efficacy (95%CI), The vaccine cost per course (±25% from the base case), and The discount rate (3% used in studies conducted in other

industrialized countries.

Result and Discussion

Table3: Base case result

Outcome No program With program Difference Reduction(%)

No. of events

Hospitalizations 32,900 1,592 -31,308 95

Outpatients Visits 6,78,218 1,01,731 -576,487 85

Direct medical cost ¥

Vaccination cost 0 22,000,000,000 22,000,000,000

Hospitalizations 4,281,782,278 207,097,440 -4,074,684,838 95

Outpatients Visits 8,828,124,134 1,324,196,483 - 7,503,927,651 85

Indirect medical cost, ¥

Hospitalizations 1,193,343,477 57,718,577 - 1,135,624,900 95

Outpatients Visits 9,841,794,497 1,476,244,496 - 8,365,550,001 85

Table 3 Cont…Outcome No Program With Program Difference Reduction(%)

Total cost, ¥

Healthcare system 13,109,906,412 23,531,293,923 10,421,387,511 -79

Societal 24,145,044,386 25,065,256,995 920,212,609 － 4

QALY loss 1,219 153 -1,066 87

ICER per QALY gained, ¥

Healthcare system 9,780,524 (Not cost-effective)

Societal 8,63,624 (Highly cost-effective)

Fig 1: Cost structure of rotavirus hospitalizations and out patient visit before the implementation of rotavirus vaccination

Fig 2 : The direct medical cost and indirect medical cost of rotavirus hospitalization and out patient visits according to the incidence of the hospitalization and outpatient visit

Fig 3 : Sensitivity Analysis result

Fig 4 : Sensitivity Analysis result (Health care perspective)

Fig 4 : Sensitivity Analysis result (Societal perspective)

Conclusion:

• A universal rotavirus immunization program would prevent 85% of the rotavirus-associated hospitalizations and outpatient visits.

• The universal immunization program was found to be cost-effective from the societal perspective for any of the previously reported incidence rates of rotavirus-associated hospitalization.

• Thus, the introduction of the rotavirus vaccine into the childhood immunization schedule and its co-administration with other childhood vaccines will be a cost-effective public health intervention in Japan.

Limitation of this study

Authors did not consider any effects that may arise from the differences in the serotypes.

The events of rotavirus deaths, nosocomial infections, and home care cases were not included because of the non-

availability of the relevant data. This model did not take herd immunity into account.

Success story

• Australia, where rotavirus vaccine was introduced into the universal immunization program since 2007, a cost-effectiveness analysis showed that the ICER per QALY gained from the implementation of the immunization program was lesser than the maximum cost-effectiveness threshold when the base case incidence of rotavirus- associated hospitalizations was applied.