Cost analysis of two strategies for hepatitis A vaccination of hospital health-care personnel in an intermediate endemicity area

Hepatitis A in internationally adopted children: screening for acute and previous infections

OBJECTIVE

The goal was to determine the prevalence of acute hepatitis A virus (HAV) infection and immunity among internationally adopted children.

METHODS

Children seen at the International Adoption Center between September 25, 2006, and September 30, 2008, and were screened for HAV within 4 months after their arrival in the United States were eligible for the study. The age- and country-specific prevalence of acute HAV infection and immunity were determined.

RESULTS

Overall, 288 children underwent HAV serological testing. Of the 279 with total HAV serological results, 29% had positive findings. Immunity varied according to region and country. The prevalence was lowest among children born in Asia/Pacific Rim region (17%) and highest among children born in Africa (72%). Only 13% of children <2 years of age were immune, compared with 80% of children 12 to 17 years of age (P = .002). Increasing age and birth region were associated independently with immunity. Positive HAV immunoglobulin M test results were found for 3 (1%) of 270 children; all were without symptoms. Their ages were 18, 27, and 41 months, and they were born in Kazakhstan, Russia, and the Latin America/Caribbean region, respectively. The father of 1 child developed HAV infection after arriving home.

CONCLUSIONS

HAV immunity among internationally adopted children varied according to age and country of origin; 1% had acute infections. HAV screening is useful for determination of the need for HAV immunization and for prevention of transmission to family members and close contacts.

[Hepatitis A virus seropositivity among healthcare workers at a university hospital in Korea]

BACKGROUND

Healthcare workers (HCW) are known as a risk group of hepatitis A virus (HAV) infection and vaccination of this group against HAV has been suggested. However, the seroprevalence of HAV antibody among HCW in Korea has not been reported. We investigated the seropositivity of HAV antibody in HCW, to obtain a baseline data.

METHODS

We measured serum total HAV antibody using chemiluminescent immunoassay (ADVIA Centaur, Germany) in 174 HCW at one university hospital in Seoul, Korea.

RESULTS

Serum HAV antibody was positive in 48 (27.6%) of 174 subjects tested. The seropositivity of HAV antibody was significantly increased with increasing age: 21.1% (26/123), 55% (22/40), and 100% (11/11) in the age groups of 20's, 30's, and 40's, respectively (P<0.001). However it was not significantly different among different occupations (physicians 38%, nurses 24.6%, other workers 31.4%, P=0.376) and work places (medical ward 29.1%, pediatric ward 25.9%, emergency room 34.4%, laboratory 0%, P=0.140). The seroprevalence rate of HAV antibody in the age groups of 20's and 30's in this study was not higher than that of previous studies on non-HCW populations in Korea since 2006.

CONCLUSIONS

The seroprevalence of HAV antibody among HCW in the age groups of 20's and 30's in a Korean hospital was not higher than that of non-HCW populations, and the seropositivity increased with increasing age. Further studies are needed for the age-specific strategy for vaccination, considering the increased risk of exposure in HCW to HAV infection in hospital environment with the increase of symptomatic patients with HAV.

Vaccination strategies against hepatitis A in travelers older than 40 years: an economic evaluation

BACKGROUND

In recent years, the number of travelers aged >40 years who acquire hepatitis A while traveling has increased. Therefore, there is a need to review hepatitis A vaccination protocols in travelers. The aims of the study were to assess immunity levels to hepatitis A virus (HAV) in international travelers >40 years and to determine the least costly immunization strategy.

METHODS

A serological examination of HAV antibodies in 427 international travelers aged >40 years traveling endemic zones was carried out. The prevalence of antibodies in each age group was assessed. The costs of two preventive strategies, direct vaccination of all subjects (independent of the immune status) or screening and subsequent vaccination of susceptible subjects were compared. The critical value of prevalence (CVP) (the value at which the costs for the two strategies are equal) was calculated.

RESULTS

Total prevalence of HAV antibodies was 78.9% [95% confidence interval (CI): 74.8-82.5] and was 80.0% (95% CI: 73.8-85.2) in men and 77.9% (95% CI: 71.9-83.2) in women. There was a positive association with age. In the 40 to 49, 50 to 59, 60 to 69, and 70 to 95 years age groups, the prevalence rates were 62.6 (95% CI: 53.8-71.5), 76.8 (95% CI: 70.0-82.7), 91.7 (95% CI: 85.2-95.6), and 97.5% (95% CI: 87.4-99.6), respectively. The CVP was 58.4% using two doses of vaccine.

CONCLUSIONS

The CVP was lower than the prevalence rate found in our international travelers. Therefore, we recommend systematic screening for HAV antibodies before selective vaccination of international travelers aged >40 years traveling to hepatitis A endemic zones.

Costing infectious disease outbreaks for economic evaluation: a review for hepatitis A

With the aim to understand and estimate the economic impact of outbreaks of community-acquired infections, we performed a review focusing on hepatitis A outbreaks, and retained 13 papers that had collected relevant cost information during such outbreaks. All costs in this article are expressed in USD, year 2007 values. The costs of hepatitis A outbreaks ranged from USD140 000 to US36 million, and the costs per case in an outbreak situation ranged from USD3824 to USD200 480. These costs were typically found to be substantially higher than estimates from cost-of-illness studies (i.e. costs for sporadic cases) and estimates used in cost-effectiveness analyses, mostly because of costly outbreak-control measures. Post-exposure prophylaxis is a major cost factor, especially for food-borne outbreaks. As a result of the increasing proportion of those susceptible to hepatitis A in low-incidence countries, future outbreaks could, on average, increase in size. The increasing occurrence of hepatitis A cases in outbreak situations and the associated control costs should appropriately be accounted for in economic evaluations of vaccination programmes in low-incidence countries. In order to do this, more studies documenting such outbreak-control strategies in terms of costs and resource use are needed.

The risk of hepatitis A infection among healthcare workers: a review of reported outbreaks and sero-epidemiologic studies

All reports of hepatitis A (HA) outbreaks in healthcare settings published between 1975 and 2003 were studied to determine the background immunity or susceptibility of healthcare workers (HCWs) to HA. Twenty-six reports were found. The number of infected personnel ranged from one to 66 and, in most outbreaks, nurses accounted for the majority of personnel infected, reflecting high attack rates reaching 15-41%. In addition, we found 23 sero-epidemiological studies for HA among HCWs that had been performed in 13 different countries. Seroprevalence rates of HCWs with anti-HA antibody ranged between 4% among paramedical workers in Germany to 88% among hospital maintenance workers in Portugal. Effective infection control of HA outbreaks in hospitals demands early recognition, including awareness of atypical presentations of the infection, and strict adherence to universal infection control measures. Education programmes are of special importance for HCWs in neonatal, paediatric and intensive care units. The findings of the current study suggest that a pre-employment screening policy and administration of active vaccination to susceptible HCWs, particularly nurses, should be seriously considered in high-risk settings.

Hepatitis vaccines: recent advances

Despite the availability of hepatitis A vaccines that might provide protection for decades, hepatitis B vaccines that provides protection for at least 15 years and the recent introduction of a combined hepatitis A and B vaccine, these infections continue to spread in both the developed and developing world. Hepatitis A vaccine coverage has been limited to high-risk groups: such a selective immunisation policy is unlikely to have a major impact. If adequate immunogenicity in infants is confirmed, dosing schedules can be improved and the costs of vaccination reduced, universal paediatric immunisation with combined hepatitis A and B products is likely to result in the eventual eradication of these infections. In the interim, novel hepatitis A vaccines are being investigated and additional studies on hepatitis A vaccine immunogenicity in infants are in progress. Worldwide use of hepatitis B vaccines for the newborn, young children and high-risk groups should control this infection and obviate the need for a vaccine against hepatitis D. Newer hepatitis B vaccines that may reduce the likelihood of non-responsiveness and have immunotherapeutic value are under study. A recombinant hepatitis E vaccine for use in endemic regions is currently in clinical trials. The development of an effective hepatitis C vaccine has been agonisingly slow and many impediments have been recognised. These include the lack of a susceptible small animal, a high degree of hepatitis C virus (HCV) genomic diversity and failure to produce high quantities of HCV in tissue culture. The development of a novel HCV replicon system may be a major breakthrough. Nonetheless, it may still be exceedingly difficult to produce a vaccine that uniformly provides sterilising immunity; the possibility of developing a hepatitis C vaccine that can prevent chronic infection is an exciting concept that requires further investigation. Advances in recombinant technology, the use of novel genetic (DNA-based) vaccines, expression of hepatitis antigens in plants and improved adjuvants also hold considerable promise.

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.