Cost effectiveness of vaccinating food service workers against hepatitis A infection

Hepatitis a Vaccine as Opportunity of Primary Prevention for Food Handlers: A Narrative Review

The hepatitis A virus (HAV) is still a leading cause of viral hepatitis worldwide. After a long incubation period, the clinical manifestations range from asymptomatic infection to acute liver failure. The severity of the disease increases with age and pre-existing liver disease. The transmission is mainly via person-to-person contact or ingestion of contaminated food or water. Food contamination can occur at any step of the food chain, especially when infected people handle not-heated or otherwise-treated food. HAV is endemic in low-income countries because of poor sanitary and sociodemographic conditions. The populations of developed countries are highly susceptible, and large outbreaks occur when HAV is introduced from endemic countries due to globalization, travel, and movement of foodstuffs. HAV prevention includes hygiene practices, immunoglobulins, and vaccination. Safe and effective inactivated and live attenuated vaccines are available and provide long-term protection. The vaccine targets are children and subjects at increased risk of HAV exposure or serious clinical outcomes. This review discusses the critical role of food handlers in the spread of HAV and the opportunity for food industry employers to consider food handler immunization a tool to manage both food safety in compliance with HACCP principles and food operators' biologic risk.

Hepatitis A and considerations regarding the cost-effectiveness of vaccination programs

Hepatitis A vaccines have demonstrated a high degree of immunogenicity and an excellent safety profile. Immunization of certain populations and patient subgroups is recommended according to specific epidemiological and clinical factors, such as a greater likelihood of acquisition of infection or concerns regarding the risk of development of fulminant hepatitis and death. Therefore, the economic implications of routine and/or targeted vaccination programs in the general population and high-risk individuals have been examined. In this manuscript, the available data from the literature regarding the cost-effectiveness of hepatitis vaccination programs in healthy individuals and in those with chronic liver disease are reviewed.

A review of interventions triggered by hepatitis A infected food-handlers in Canada

Background

In countries with low hepatitis A (HA) endemicity, infected food handlers are the source of most reported foodborne outbreaks. In Canada, accessible data repositories of infected food handler incidents are not available. We undertook a systematic review of such incidents to evaluate the extent of viral transmission through food contamination and the scope of post-exposure prophylaxis (PEP) interventions.

Methods

A systematic search of MEDLINE and EMBASE was conducted to identify published reports of incidents in Canada. An expanded search of a news repository (i.e., transcripts from newspapers and newscasts) was also conducted to identify the location and timing of an incident, which was used to retrieve the related report by contacting local public health departments. Data pertaining to case identification, public health risk, PEP interventions, and associated costs was independently abstracted by two reviewers and summarized according to incidents with and without large PEP interventions.

Results

A total of 16 incidents were identified from 1998–2004. There were approximately 3 incidents requiring public notification per year. Only 12.5% of incidents were described in published reports, indicating that published data significantly underestimated the number of incidents and PEP interventions. Data pertaining to the remaining incidents was unpublished, sparse and highly dispersed at the local public health level.

Six of the 16 incidents required large PEP interventions to immunize on average 5000 potentially exposed individuals. Secondary transmission was low. Characteristics of incidents requiring large PEP interventions included potentially infectious food handlers working with uncooked food for a prolonged duration in high-volume grocery stores in high-density urban areas.

Conclusion

Infected food handlers with hepatitis A virus (HAV) requiring public notification are not infrequent in Canada. Published data severely underestimated the burden of PEP intervention. Better and consistent reporting at the local and national level as well as a national data repository should be considered for the management of future incidents.

Outbreak of infection with hepatitis A virus (HAV) associated with a foodhandler and confirmed by sequence analysis reveals a new HAV genotype IB variant

An outbreak of infection with hepatitis A virus associated with a foodhandler and involving 26 subjects occurred in Southern Italy. Sequence analysis of the VP3-VP1 and VP1-P2A junctions confirmed that the outbreak was due to a point source and allowed the identification of a new genotype IB variant. This report confirms the usefulness of sequence-based molecular fingerprinting during outbreaks.

Hepatitis A Transmitted by Food

Hepatitis A is caused by hepatitis A virus (HAV). Transmission occurs by the fecal-oral route, either by direct contact with an HAV-infected person or by ingestion of HAV-contaminated food or water. Foodborne or waterborne hepatitis A outbreaks are relatively uncommon in the United States. However, food handlers with hepatitis A are frequently identified, and evaluation of the need for immunoprophylaxis and implementation of control measures are a considerable burden on public health resources. In addition, HAV-contaminated food may be the source of hepatitis A for an unknown proportion of persons whose source of infection is not identified.

Economic impact of a hepatitis A epidemic in a mid-sized urban community: the case of Spokane, Washington

Data reported here represent an effort to build on previous work regarding the costs of hepatitis A. We expand this work to include an estimation of the costs of hepatitis A on a community wide basis. In addition to calculating the costs of disease management and health care delivery, we include an analysis of additional child care costs, lost productivity, costs associated with outbreak management, and the impact on affected restaurants that required public notification and the administration of Immune Globulin to patrons. The work reported here is specific to Spokane county, Washington. The objective is to enable the Spokane Regional Health District to communicate to the community costs of managing an outbreak of hepatitis A and to inform implementation of a hepatitis A vaccination program on a community wide basis. The average cost (direct and indirect) per case for the entire sample is 2,683 dollars. The estimated total cost for the sample (145 cases) is approximately 370,193 dollars. Inpatient hospital care is the largest direct medical expense and lost productivity is a major indirect cost to the community. Lessons learned from undertaking this task include: (1) costs incurred are not immediately obvious, (2) without infrastructure in place, tracking costs is difficult, if not impossible, (3) potential for large expenditures is apparent, (4) estimates are consistent with those generated in previous studies, and (5) previous findings of vaccination of certain high-risk populations as a cost-efficient approach is corroborated.

Cost-effectiveness of hepatitis A vaccination in children, adolescents, and adults

Hepatitis A is a major public health problem in the United States and other developed countries, largely because decreased natural immunity allows for increased susceptibility. To evaluate the cost-effectiveness of routine vaccination of children, adolescents, and certain high-risk adults against hepatitis A, economic analyses of hepatitis A vaccination were identified through searches of MEDLINE, EMBASE, and BIOSIS (February, 1992, to December, 2001) for studies, reviews, editorials, and letters from peer-reviewed journals published in English, French, German, Italian, or Spanish. Experts were also contacted. Articles conforming to accepted standards of quality for health-economic studies were used to compile data on vaccination of children, and results were synthesized in a narrative review. This review of economic analyses of vaccine use in several developed countries shows cost-effectiveness comparable with that of other vaccines in children and within accepted boundaries for adolescents and high-risk adults.

Foodborne illness: new developments concerning an old problem

Foodborne illnesses continue to cause substantial morbidity and mortality in the United States, primarily as gastroenteritis but occasionally as other syndromes as well. Most of these illnesses are caused by a variety of widely known infectious agents, principally viruses, and are probably the result of common mistakes in food handling in the home or in restaurants. The epidemiology of foodborne illness is evolving. Major changes in food production, distribution, and consumption have created opportunities for new pathogens to emerge and for old ones to reemerge, and the potential for widespread outbreaks is increasing. Antibiotic resistance in bacterial pathogens resulting from the widespread use of antimicrobial agents in animal husbandry is also an important concern. Clinicians must be aware of the changing epidemiology of foodborne illness to recognize and manage these conditions in the clinical setting. In addition, clinicians are critical in the reporting of recognized or suspected foodborne illness, so that public health authorities are able to investigate, understand, and ultimately better control them. A number of new techniques have been employed, and others under development will improve our ability to recognize and cope with foodborne diseases.

Inactivated hepatitis A vaccine: immunogenicity, efficacy, safety and review of official recommendations for use

There is 10 years of marketing experience with the hepatitis A vaccine Havrix. It is highly immunogenic, provides lasting protection in healthy individuals and generates protective levels of antibodies in patients with chronic liver disease or impaired immunity. Postmarketing surveillance data have confirmed the outstanding safety profile of the vaccine. The timing of the booster dose is not critical to effectiveness, which has advantages for the protection of travelers to regions of high endemicity. The vaccine is effective in curbing outbreaks of hepatitis A and also when administered postexposure, due to rapid seroconversion and the long incubation period of the disease. In intermediate endemic regions, an epidemiological shift in hepatitis A infection has driven the development of universal preventive strategies to be added to the targeting of at-risk groups. Existing official recommendations and future directions for vaccine use are reviewed.

Valuation of symptomatic hepatitis a in adults: estimates based on time trade-off and willingness-to-pay measurement

BACKGROUND

The cost effectiveness of hepatitis A prevention is typically assessed by comparing vaccination costs with the number of life-years saved. This endpoint does not consider the benefits of preventing nonfatal yet symptomatic infections. Nearly as many days of healthy life are lost to hepatitis A morbidity as mortality.

OBJECTIVE

To investigate the value American adults place on preventing hepatitis A symptoms by using the willingness-to-pay and time trade-off metrics.

METHODS

We provided a written description of hepatitis A symptoms to 181 American adults, who judged the amounts of money and lifespan they would forego to avoid them. The description made no reference to the possibility of fatality, and respondents were asked not to consider costs of medical care and work loss. We investigated relationships between demographic characteristics and each metric, the relationship between the two metrics, and the test/re-test reliability of the metrics.

RESULTS

Respondents would pay a median of dollars US 2000 (inter-quartile range, dollars US 500 to 5000; 2001 values) for risk-free prevention of hepatitis A symptoms. Alternatively, they would forego a median of 28 days survival (inter-quartile range, 6 to 40 days) for cost-free prevention. There was modest correlation between willingness-to-pay and time trade-off responses (r = 0.24, p < 0.01), suggesting these metrics measure independent aspects of preference. Strong correlations between measures obtained 30 days apart support the test/re-test reliability of willingness to pay (r = 0.70, p < 0.01) and time trade-off (r = 0.73, p < 0.01) metrics. In multivariate analyses, higher household income (p = 0.02) predicted greater willingness to pay in dollars. Male gender (p < 0.01) predicted greater willingness to forego life expectancy for better health.

CONCLUSION

In our study population of US adults, most were willing to pay or trade life expectancy for a hypothetical preventative drug for hepatitis A symptoms. The amount respondents were willing to pay appears dependent on their income level while males are willing to trade more life expectancy than female respondents. The values expressed should be considered in assessments of hepatitis A prevention.