This is a critical abstract of an economic evaluation that meets the criteria for inclusion on NHS EED. Each abstract contains a brief summary of the methods, the results and conclusions followed by a detailed critical assessment on the reliability of the study and the conclusions drawn.

Vaccination programmes for hepatitis B.

Screening and primary prevention.

Cost-effectiveness analysis.

Four hypothetical populations were considered in the study: the French general population, young adult men (aged 15-40), homosexual men and intravenous drug users.

The setting was primary care. The study was conducted in France.

Some effectiveness data were derived from previous studies conducted between 1990 and 1993. Dates for resource data were not specified. The price year was 1990.

The effectiveness data was based on authors' assumptions.

The authors produced a model to determine the final cost and benefits.

Authors' assumptions. In making their assumptions the authors were in part influenced by published studies.

The sensitivity and specificity of the screening test were acknowledged to be inferior to 100%. The base case solution assumed a non-response rate to vaccination of 0.05 and a compliance of 100%.

The sensitivity and specificity rates of the screening test, non-response and compliance rates over a five-year period.

Costs and quantities were not reported separately. Direct costs were obtained for screening (vaccination and GP/specialist consultations), based on social security reimbursement figures, and three potential outcomes for those developing symptoms as follows:

The annual care of patients suffering from symptomatic hepatitis for two possible outcomes; one involving a period of hospitalisation (based on an 8 day average stay) for 25% of cases, and one involving no hospitalization period for 75% of cases.

The annual costs of care for patients developing either chronic hepatitis or cirrhosis of the liver after hospitalisation. These data were obtained by examining 116 case records from four hospitals in France, which included consultation and treatment costs for a period of one year.

The duration of costs was 20 years. A discount rate of 8% was used and costs were expressed in 1990 values.

French Francs (FF).

Sensitivity analyses were carried out on economic variables as follows: Discount rate (5, 8 and 10%), vaccination compliance rate (70 and 100%), cost of vaccination and direct medical costs of care. These were compared with the base-case solution (discount rate = 8% and compliance = 100%). This produced8 variations for each population and each of the three strategies (status quo, universal vaccination or screen and vaccinate).

The base case solution assumed a non-response rate to vaccination of 0.05 and a compliance of 100%. The sensitivity and specificity of the screening test was acknowledged to be inferior to 100%.

Total direct costs per individual were calculated for direct medical costs associated with each population and for each strategy:

(1) Status Quo: for the general population (39FF), males between 15 and 40 (148FF), homosexual men (587FF) and intravenous drug users (2875FF).

(2) Screen and vaccinate:for the general population (808FF), males between 15 and 40 (775FF), homosexual men (645FF) and intravenous drug users (678FF)

(3) Universal vaccination: for the general population (762FF), males between 15 and 40(767FF), homosexual men (789FF) and intravenous drug users (974FF).

The study showed that when compared with the comparator of maintaining the status quo (i.e. adopting no specific programme) screening and vaccinating was cost-effective for homosexual men for three variants of the base-case solution and was cost-effective for all variant solutions for intravenous drug users.

The authors concluded that universal vaccination was not a cost-effective strategy and that screen and vaccinate strategies become cost-effective for attack rates close to homosexual men and always for intravenous drug users. The optimal strategy would be to screen and vaccinate the drug user population.

1. Although the study considered hypothetical populations it took into account all relevant economic and epidemiological factors and made use of case records and official reimbursement levels to determine the costs associated with each strategy.

2. Justification for the effectiveness of the vaccine (assumed to produce a non-response rate of 5%) was not clearly stated, and was assumed to have been determined by clinical judgement. If significantly different from this figure it would have had an effect on the cost-effectiveness findings.

3. The source of the effectiveness data used in the study, as well as the presentation of the analysis was not always clear. There was a contradiction in the reporting of the price year.

Research was funded by CNAMTS