Cost effectiveness of antenatal hepatitis B screening and vaccination of infants

Cost-Effectiveness of HBV and HCV Screening Strategies--A Systematic Review of Existing Modelling Techniques

Introduction

Studies evaluating the cost-effectiveness of screening for Hepatitis B Virus (HBV) and Hepatitis C Virus (HCV) are generally heterogeneous in terms of risk groups, settings, screening intervention, outcomes and the economic modelling framework. It is therefore difficult to compare cost-effectiveness results between studies. This systematic review aims to summarise and critically assess existing economic models for HBV and HCV in order to identify the main methodological differences in modelling approaches.

Methods

A structured search strategy was developed and a systematic review carried out. A critical assessment of the decision-analytic models was carried out according to the guidelines and framework developed for assessment of decision-analytic models in Health Technology Assessment of health care interventions.

Results

The overall approach to analysing the cost-effectiveness of screening strategies was found to be broadly consistent for HBV and HCV. However, modelling parameters and related structure differed between models, producing different results. More recent publications performed better against a performance matrix, evaluating model components and methodology.

Conclusion

When assessing screening strategies for HBV and HCV infection, the focus should be on more recent studies, which applied the latest treatment regimes, test methods and had better and more complete data on which to base their models. In addition to parameter selection and associated assumptions, careful consideration of dynamic versus static modelling is recommended. Future research may want to focus on these methodological issues. In addition, the ability to evaluate screening strategies for multiple infectious diseases, (HCV and HIV at the same time) might prove important for decision makers.

Infection with hepatitis B and C virus in Europe: a systematic review of prevalence and cost-effectiveness of screening

BACKGROUND

Treatment for chronic hepatitis B virus (HBV) and hepatitis C virus (HCV) infection is improving but not benefiting individuals unaware to be infected. To inform screening policies we assessed (1) the hepatitis B surface antigen (HBsAg) and anti-hepatitis C virus antibody (anti-HCV-Ab) prevalence for 34 European countries; and (2) the cost-effectiveness of screening for chronic HBV and HCV infection.

METHODS

We searched peer-reviewed literature for data on HBsAg and anti-HCV-Ab prevalence and cost-effectiveness of screening of the general population and five subgroups, and used data for people who inject drugs (PWID) and blood donors from two European organizations. Of 1759 and 468 papers found in the prevalence and cost-effectiveness searches respectively, we included 124 and 29 papers after assessing their quality. We used decision rules to calculate weighted prevalence estimates by country.

RESULTS

The HBsAg and anti-HCV-Ab prevalence in the general population ranged from 0.1%-5.6% and 0.4%-5.2% respectively, by country. For PWID, men who have sex with men and migrants, the prevalence of HBsAg and anti-HCV-Ab was higher than the prevalence in the general population in all but 3 countries. There is evidence that HCV screening of PWID and HBsAg screening of pregnant women and migrants is cost-effective.

CONCLUSION

The prevalence of chronic HBV and HCV infection varies widely between European countries. Anti-HCV-Ab screening of PWID and HBsAg screening of pregnant women and migrants have European public health priority. Cost-effectiveness analyses may need to take effect of antiviral treatment on preventing HBV and HCV transmission into account.

Hepatitis B immunisation coverage of infants born to chronic carrier mothers in Victoria

Infants born to HBsAg- (hepatitis B surface antigen) carrier mothers are highly likely to become chronic hepatitis B (HB) carriers themselves unless their status is recognised at birth and they are immunised with three doses of HB vaccine, the first within 48 hours of birth, concurrent with hepatitis B immune globulin (HBIG). This study was designed to determine how many infants born in Victoria to carrier mothers completed three doses of HB vaccine. We sent the names of all infants of HBsAg-carrier mothers notified in Victoria between 1.7.91 and 30.6.92 to the appropriate local government immunisation providers and requested information on how many doses of HB vaccine, DTP (diphtheria-tetanus-pertussis) or CDT (combined diphtheria-tetanus), and OPV (oral polio vaccine) they had received. The HBsAg-carrier prevalence of women giving birth in Victoria in 1991-92 was at least 0.52%. Of the 336 infants notified, 239 (71.1%) were recorded in local government records. Of these 239, 90.8% received at least two doses and 80.8% received at least three doses of hepatitis B vaccine. There was no significant difference in the number who received three doses of HB vaccine compared with three doses of DTP or CDT vaccine. Of the entire cohort of 336, only 57.4% were documented as being completely immunised against hepatitis B. HB immunisation coverage for these infants needs to be improved. The high rate of loss to follow-up, especially between the maternity hospital and the community, is disturbing. Mechanisms for intensive prospective follow-up of these infants should be developed to prevent loss to follow-up and to encourage full immunisation against HB. Improving HB immunisation coverage of infants in high HBsAg-prevalence ethnic groups and introduction of universal infant HB immunisation may lead to increased coverage of infants of carriers by serving as back-up mechanisms for those lost to follow-up.

An appraisal of the efficacy and cost effectiveness of antenatal screening for hepatitis B

In this review published data are used to determine the benefits and costs of antenatal screening for hepatitis B carriers to prevent the later occurrence of hepatoma and chronic liver disease in their offspring. In Britain, babies born to carrier mothers have a 25% risk of perinatal infection and of becoming carriers themselves (the risk is 82% if their mothers are positive for the e antigen and 10% if negative). The carrier state increases the risk of hepatoma an estimated 86 times and the risk of chronic liver disease 20 times. Life table analysis showed that there is an 11% lifetime risk in carriers in Britain of dying from hepatoma (which results in seven years of life lost on average) and a 7% risk of chronic liver disease (14 years of life lost). Neonatal vaccination reduces the risk of the infant becoming a carrier by about 90%. Perinatal transmission occurs in 38 of every 100,000 neonates in Britain. Antenatal screening of all women and vaccinating babies of carrier mothers would prevent perinatal transmission in 34 of the 38 children (90%), or 255 per year in Britain. Of these 34, 8.4 children would be Chinese in ethnic origin, 4.2 African, 11.5 South Asian (from the Indian subcontinent), 2.0 Caribbean, and 7.3 would be white. Six deaths in the 34 from hepatoma or chronic liver disease caused by hepatitis B would then be prevented. The direct cost in Britain of screening all women, irrespective of ethnicity, at their first pregnancy only, would be 1300 pounds for each year of life saved (undiscounted) or 2500 pounds if screening at every pregnancy. Screening just Chinese, Africans, and South Asians, at first pregnancy only, would cost 330 pounds for each year of life saved but would prevent only 64% of these deaths. Vaccinating the infants of carrier mothers is likely also to prevent horizontal transmission of hepatitis B in early childhood and prevent the carrier state developing in an estimated three extra children for each child protected from vertical transmission. When this is taken into account the number of deaths prevented increases fourfold, reducing the cost for each year of life saved by 75%. Screening all women at first pregnancy only is an acceptably cost effective policy in Britain (1300 pounds for each year of life saved), actually preventing 45 deaths a year from hepatoma and chronic liver disease (or about 180 deaths if those horizontally infected are included), at a total cost of 540,000 pounds a year. It has the advantage of being comprehensive, equitable, and easier to implement than a policy based on screening of high risk ethnic groups.

The incidence of hepatitis B infection in Australia: an epidemiological review

Hepatitis B virus (HBV) infection in Australia remains a significant problem despite the availability of an inexpensive vaccine. National information about incidence, prevalence, morbidity and the extent of vaccine coverage is incomplete; improved surveillance would allow for better targeting and evaluation of prevention activities. Our estimates indicate that 75%-90% of cases of vertical transmission of HBV are preventable through vaccination of newborns whose mothers are carriers.

Is vaccination against hepatitis B efficient? A review of world literature

We report on the result of a study aimed at assessing the variability of assumptions upon which economic models for the introduction of vaccination against Hepatitis B are based, the conclusions reached and define a minimum set of methodological standards upon which future economic studies on vaccines should be based. We identified 116 published and unpublished works by Medline literature searches, consulting private databases and corresponding with all authors and researchers active in economic evaluation of vaccines. All works were assessed but we included in our review only those which were original economic analyses (90 studies). Principal epidemiological and economic variables were extracted and compared where possible. Rough manipulations were carried out to make the data comparable. We found profound variability on the main parameters of the efficiency equation (disease incidence, costing methods, use of marginal theory, discounting and study time-span, sensitivity analysis and reporting methods). We also found inconsistencies in definition and study design in 38% of a subset of studies. Although we found scarce decision-making impact, we believe that due to uncertain or unclear methodology, few studies reach valid conclusions. In future decisions may be based on biased evidence and scarce resources committed to untested programmes. There is an urgent need to standardise study methods and define a common set of procedures.

Cost-effectiveness analysis of prenatal screening and vaccination against hepatitis B virus--the case of Belgium

The study examines the cost-effectiveness of screening pregnant women in Belgium for the presence of hepatitis B virus (HBV) and of vaccinating the newborns if necessary. The alternative strategy considered is 'doing nothing'. The rate of carriership among a sample of pregnant women in Belgium amounts to 0.67%. If a pregnant woman is a carrier of the virus, there is an average probability of 30% that she will transmit the virus to her newborn. Later in life, this baby will be at risk from serious complications, such as chronic active hepatitis, cirrhosis and primary hepatocellular cancer. However, medical costs will be induced by screening and vaccination campaigns, lab-tests, vaccine costs, etc. On the other hand, resources will be saved by the prevention of severe complications of the disease. However, costs dominate savings, the incremental cost-effectiveness ratio for the screening and vaccination strategy amounting to 583,581 BEF per life-year saved. To check the stability of the cost-effectiveness ratio, a sensitivity analysis has been performed on some crucial parameters: the ratio is found to be sensitive to the prevalence of HBV among pregnant women, to the costs for screening and vaccination and to the discount rate. Increasing the treatment costs for a HBV complication hardly changes the cost-effectiveness ratio.