Vaccines to prevent viral hepatitis

Hepatitis B virus infection and vaccination among young injection and non-injection drug users: missed opportunities to prevent infection

INTRODUCTION

We examined correlates of HBV infection and vaccination and the missed vaccination opportunities among young injection drug users (IDUs) and non-injection drug users (NIDUs).

METHODS

Two hundred IDUs and 124 NIDUs aged 15-30 years were studied. Demographics, drug use and sexual behaviors, and health and incarceration history data were collected. Serology was conducted for antibodies to HBV-core antigen (anti-HBc) and HBV-surface antigen (anti-HBs). Presence of anti-HBc indicated past HBV infection; presence of anti-HBs alone indicated past vaccination.

RESULTS

More IDUs had been infected with HBV in the past than NIDUs (37% versus 19%, P = 0.001). Among male and female IDUs, injection drug use behaviors were significantly associated with past infection. For female IDUs, being African-American and trading sex were also associated with previous infection. Among NIDUs, being female and longer time since sexual debut were associated with past infection. Overall, 11% were vaccinated (10% IDU versus 14% NIDU, P = 0.30). Younger age and drug treatment history were associated with vaccination. Most susceptibles (84%) experienced at least one missed opportunity for vaccination.

CONCLUSION

Young drug users remain at high risk for HBV infection. Vaccination rates remain low despite multiple opportunities for vaccination. An integrated HBV immunization effort should be coordinated among venues frequented by young drug users.

Comparison of the accelerated and classic vaccination schedules against Hepatitis B: three-week Hepatitis B vaccination schedule provides immediate and protective immunity

Background

Hepatitis B virus infection although preventable by vaccination remains an important health issue throughout the world due to its morbidity, mortality and economical losses. Early seroprotection is desirable for people at high risk of exposure. The aim of this study was to determine whether three-week hepatitis B vaccination (on days 0, 10 and 21) provide seroprotection or not.

Methods

The 120 subjects enrolled into the study were divided into two groups and vaccinated by the classic (months 0, 1, and 2) or the accelerated (days 0, 10, and 21) schedules and antibody response determined on days 30, 60, and 90 and, if below 10 mIU/ml^-1, again on day 180. For each individual in the classic group (B) three subjects were enrolled in the accelerated group (A). Recombinant hepatitis B vaccine (Gen-Hevac B, Pasteur) was given as 20 micrograms intramuscular injections via the deltoid muscle. A booster dose on day 365 was administered for each group. Family members of hepatitis B carriers and volunteer health personnel were enrolled into group A. To the B group only volunteers who wanted vaccination against hepatitis B were included.

Results

After three doses of vaccine, Anti-HBs titers reached protective levels in both groups. The number of vaccinees with seroprotective levels of Anti-HBs (≥10 mIU/ml^-1) on day 30 was 53 (58.9%) in group A and 9 (30.0%) in group B (p < 0.05). On day 60, there was no difference between group A and B, with response rates of 84.4% (n = 76) and 80.0% (n = 24) respectively (p > 0.05). On day 90 there was no difference between group B and group A; with 26 (86.7%) and 79 (87.7%) responders respectively. In both groups those with Anti-HBs levels <10 mIU/ml^-1 attained protective levels by day 180.

Conclusion

In this study, the three-week vaccination provided protective antibody titers within a shorter time compared to the classic schedule. Therefore, in order to provide rapid antibody production against hepatitis B virus, the accelerated vaccination schedule seems to be a good preference.

Hepatitis B vaccine nonresponse and celiac disease

OBJECTIVES

There is a genetic predisposition to hepatitis B vaccine nonresponse. The link between human leukocyte antigen (HLA) genotype and ineffective development of immunity to the hepatitis B vaccine has been characterized in multiple studies. Celiac disease has a strong association with a particular HLA genotype of DQ2; interestingly, this HLA genotype is seen in association with nonresponders to the hepatitis B vaccine. We report a disproportionate number of patients with celiac disease who are nonresponders to the hepatitis B vaccine series.

METHODS

We reviewed the hepatitis B vaccine records, serological tests for anti-hepatitis B surface antigen antibody (anti-HBs), and HLA genotypes of celiac disease patients identified as nonresponders to hepatitis B vaccine. Subjects were identified from a database of patients diagnosed with celiac disease at our institution or referred to our center for evaluation and management of celiac disease between November, 2000, and October, 2002.

RESULTS

A total of 23 subjects were reviewed. All had a clinical and pathological diagnosis of celiac disease. All subjects reported receiving the full series of hepatitis B vaccinations. Of the subjects, 19 had testing for hepatitis B vaccine response. Of these 19 subjects, 13 did not achieve long-term immunity as seen by the negative qualitative or quantitative anti-HBs antibody titer. All tested subjects were either homozygous or heterozygous for DQ2.

CONCLUSIONS

We postulate that celiac disease patients may have a significant predisposition to hepatitis B vaccine nonresponse. Both celiac disease and hepatitis B vaccine nonresponse is genetically mediated. Celiac disease patients may have a failure of induction of humoral immune response needed for development of long term immunity; the mechanism for this is unclear.

Medical biotechnology in India

The potential of biotechnology has just began to emerge in the 20th century. After the full knowledge of human genomes is available, biotechnology is going to play a major role in shaping the concept of future drug discovery, drug delivery, diagnostic methodology, clinical trials, and to a great extent the major lifestyle of the human society. This article is a comprehensive review of the major impact of biotechnology in diagnostics, antibiotics, r-proteins, vaccines, and antibodies production. It also highlights the future aspects of gene therapy in the management of healthcare. A comprehensive list of biotech products in healthcare management has been given. Also, the growth of biotechnology throughout the world at large and in the Indian industries in particular has been highlighted. Constraints, concerns and difficulties in biotechnology in India have been addressed mainly related to human resources, training institutions in India, funding in biotechnology, patent-related issues and regulatory hurdles. Like in information technology, India has great potential in bioinformatics as well. Some of the recent information on bioinformatics centers in India has been summarized. Indian biotechnology industries have the potential to use the modern discoveries in life sciences to reach an enviable position in the world of biotechnology.

Immunization with recombinant Calmette-Guerin bacillus (BCG)-hepatitis C virus (HCV) elicits HCV-specific cytotoxic T lymphocytes in mice

Since virus-specific cytotoxic T lymphocytes (CTLs) play a critical role in preventing the spread of hepatitis C virus (HCV), an effective HCV vaccine should be capable of eliciting HCV-specific CTLs. In the present study, we assessed the capability of a novel recombinant vaccine using an attenuated tuberculosis bacillus, Calmette-Guerin bacillus (BCG), as a vaccine vehicle to elicit HCV-specific CTLs. BCG was engineered to express the CTL epitope of HCV-non-structure protein 5a (NS5a) as a chimeric protein with alpha antigen of mycobacteria. Immunization with this recombinant BCG elicited major histocompatibility complex class I-restricted CD8(+) HCV-NS5a-specific CTLs in mice. Immunized mice showed a substantial reduction in the vaccinia virus titer compared with control mice when the immunized mice were challenged with a recombinant vaccinia virus expressing HCV-NS5a genes. These findings provide evidences for the possibility of BCG as a vaccine vector and its continued exploration as a vehicle for eliciting HCV-specific immunity.

[Hepatitis A]

Hepatitis A infection is known since the ancient Chinese, Greek and Roman civilizations but the first documented report was published in the eighteenth century. The hepatovirus belongs to the Picornaviridae family, and carries a single strand RNA. There are 7 genotypes. Antibodies of the IgM and IgA classes, during natural infections, appear early in the serum, together with the first clinical manifestations of the disease, but they may also appear at the end of the first week of infection. There is a spectrum of clinical presentation: asymptomatic infection, symptomatic without jaundice and symptomatic jaundiced. A rare fatal form of hepatitis has been described. Diagnosis of the hepatitis A infection is confirmed by the finding of IgM anti-HAV antibodies, routinely performed using an ELISA test. Treatment is supportive. Intramuscular anti-A gamma globulin is used for passive immune prophylaxis, and there is an efficient vaccine for active immune prophylaxis.

Combined two-dose hepatitis A and B vaccine (AmBirix)

One month after the last dose (i.e. at month 7), geometric mean titres (GMTs) of antibodies directed against hepatitis A virus (anti-HAV) were generally greater in participants (aged 12-15 years) receiving combined two-dose (0 and 6 months) hepatitis A and B vaccine (AmBirix) compared with the three-dose (containing one half the dose of the two active components per dose, given at 0, 1 and 6 months; Twinrix Paediatric) schedule. Moreover, at month 7 all patients had seroconverted to anti-HAV. GMTs of antibodies directed against hepatitis B surface antigen greatly exceeded the threshold for seroprotection (>/=10 mIU/mL) 1 month after the last dose of vaccine. Seroprotection rates against hepatitis B virus (HBV) were similar 1 month after completion of either a two- (97.9%) or three-dose (100%) vaccination schedule. At 24 months' follow-up, all patients tested remained positive for anti-HAV, and 93.3% and 96.2% of those treated with the two- and three-dose schedules, respectively, remained above the threshold for seroprotection against HBV. Administering the second dose in the two-dose series at 12 months rather than at 6 months did not compromise the immune response to the combined vaccine in adolescents aged 12-15 years in a randomised, multicentre trial. Local adverse events reported in the 4 days following administration of combined two-dose hepatitis A and B vaccine include pain or soreness, redness and swelling; systemic symptoms included headache, fatigue, gastrointestinal events and fever.

Seroprevalences of hepatitis B and C among health care workers in Turkey

We determined the seroprevalence of hepatitis B virus (HBV) and hepatitis C virus (HCV) among health care workers (HCWs) at Gülhane Military Medical Academy, Haydarpasa Training Hospital in Istanbul, Turkey. Between April 1998 and September 2000, 702 HCWs were included in the study. The blood samples were tested for hepatitis B surface antigen (HBsAg), hepatitis B surface antibody (anti-HBs) and HCV antibody (anti-HCV) using third-generation tests, with confirmation by reverse transcriptase-polymerase chain reaction. Seroprevalence rates were compared with those detected in 5670 blood donors during the same period. HBsAg, anti-HBs and anti-HCV were detected in 21 (3.0%), in 480 (68.4%) and in 2 (0.3%) of 702 HCWs respectively. HBsAg and anti-HCV rates were 2.1 and 0.4% in blood donors, respectively. These data show that the prevalence rates of HBV and HCV were similar with prevalence rates detected in randomized blood donors showing that universal infection-control precautions and encouraging HBV vaccination reduces HCW infection with hepatotropic viruses.

Long term antibody response to hepatitis B vaccination beginning at birth and to subsequent booster vaccination

BACKGROUND

Few studies have examined the long term persistence of antibody after hepatitis B immunization beginning at birth and the response to a subsequent challenge with a booster dose of vaccine.

METHODS

Two groups of children received hepatitis B vaccine on a schedule of birth and 1 and 6 months of age. Group 1 received recombinant vaccine and a booster dose at 5 years of age. Group 2 received plasma-derived vaccine and a booster dose at 9 years of age. Group 1 children were tested for antibody after the primary vaccine series. All children were tested for antibody before administration of the booster dose and at 2 and 4 weeks and 1 year after the booster. In addition all children were tested for markers of hepatitis B virus infection.

RESULTS

Antibody testing conducted after the primary series for children in Group 1 (n = 70) showed that 90% had protective antibody concentrations at 13 months of age, and testing before the booster dose showed that 41% had protective antibody concentrations. All children with protective antibody concentrations after the primary series had an anamnestic antibody response to the booster dose. In Group 2 (n = 41) 39% of children had protective antibody concentrations before the booster dose, and 93% had an anamnestic antibody response to the booster dose. One year after the booster dose there were 26-fold and 11-fold declines in antibody concentration in Groups 1 and 2, respectively.

CONCLUSIONS

A primary vaccination series with either plasma-derived or recombinant hepatitis B vaccine affords long term protection for children when vaccinated beginning soon after birth.

Viral hepatitis in international travellers: risks and prevention

Viral hepatitis is caused by a number of unrelated hepatotrophic viruses, known and unknown. Five hepatitis viruses namely HAV, HBV, HCV, HDV and HEV have been well characterized and the epidemiology and disease pattern of each agent has been defined. In the West, HAV, HBV and HCV are major causes of viral hepatitis. In the East, HEV is the most common cause of viral hepatitis. HAV is ubiquitous in childhood in such countries and accounts for less than 4% of disease in adults. Viral hepatitis becomes a problem to an international traveller when he envisages a journey from low endemic to high endemic area and is susceptible to the infection endemic at his destination. Millions of such potentially susceptible travellers from Europe, the USA, Canada, Japan, Australia, and New Zealand visit endemic areas every year for various reasons. Viral hepatitis is the most common reported immunization-preventable disease among travellers to developing countries. Imported viral hepatitis incapacitates the incumbents for an average of 4-10 weeks. Considering the magnitude of the travel, the number of cases of viral hepatitis and case fatality of around 2%, the disease causes significant morbidity and mortality in such communities. It has been estimated that viral hepatitis occurs 100 times more frequently than typhoid fever and 1,000 times more often than cholera in travellers to developing countries. Hepatitis A is the most common form of viral hepatitis in travellers and cumulative data have shown a risk of 3-6 cases/1,000 persons/month of stay whereas the risk of acquiring hepatitis B is 10 times lower.

Prevalence of hepatitis A virus infection among sewage workers in Georgia

BACKGROUND

Wastewater (WW) workers could have opportunity for direct contact with raw sewage, which might contain hepatitis A virus (HAV).

METHODS

A serologic survey of WW workers and a comparison population of roads and drainage workers (RD). Factors potentially associated with anti-HAV positivity were evaluated in univariate and multivariate analyses.

RESULTS

Among the 365 WW workers, overall anti-HAV prevalence was 38%, similar to that (35%) of the 166 RD workers (P = 0.5). Prevalence varied by wastewater job type from 45% among the 164 field crew workers to 32% among the 201 treatment plant workers. In multivariate modeling, factors associated with anti-HAV positivity included age > or = 40 years (odds ratio [OR] = 2.4; 95% CI = 1.6-3.7), black compared to other races (OR = 2.4; 95% CI = 1.5-3.8), birth outside the United States (OR = 7.5; 95% CI = 3.0-18.6), a high school education or less (OR 2.1; 95% CI = 1.4-3.2) and work on the field crew compared to RD work (OR 1.6; 95% CI = 1.1-2.4).

CONCLUSIONS

These results are consistent with no or a small increased risk of hepatitis A among WW workers, and do not provide a clear mandate for hepatitis A vaccination of these workers. Am. J. Ind. Med. 43: 172-178, 2003.

Cost-reducing protein production and delivery for sexually transmitted disease prevention

Table 2 summarizes our two approaches: vaginal delivery of antibodies to immunize passively and edible microspheres for active immunization. These approaches have different roles in disease prevention in communities and each may be most useful for different kinds of diseases. The passive approach could easily be extended to lots of different sexually transmitted diseases by just changing the specificity of the antibody incorporated into the device. The active immunization approach requires more specific development steps for each particular type of disease. Detailed analysis of the cost-reduction potential of these approaches is not yet available, but estimates of the cost to manufacture these products can be made, based on the initial laboratory studies (Table 4). The results to date suggest that both products are feasible and that they could be manufactured as cheaply as other products (such as condoms and oral contraceptives) that people currently use for sexual health. All products, once made available, could have a significant impact on the reduction of healthcare costs.

Examining unmet needs in infectious disease

In the past 30 years, more than 30 new aetiological agents of infectious disease have been identified. Some of these are responsible for entirely novel and life-threatening disorders, such as AIDS, Ebola fever, hantavirus pulmonary syndrome and Nipah virus encephalitis. During the same period, some longstanding infectious diseases (such as tuberculosis) have became resurgent, as a result of a combination of complacency, increased travel and social dislocation, and also increasing drug resistance. This review looks at some of the key unmet needs in this therapeutic area and discusses strategies to address them.

Prevalence of tuberculosis, hepatitis B virus, and intestinal parasitic infections among refugees to Minnesota

OBJECTIVE

The purpose of this study was to define the prevalence of infection with Mycobacterium tuberculosis, hepatitis B virus, and various intestinal parasites among different groups of primary refugees immigrating to Minnesota.

METHODS

2,545 refugees arriving in Minnesota during 1999 received a domestic health examination that included tuberculin skin testing, hepatitis B virus serologic testing, and stool ova and parasite examinations. The Refugee Health Assessment form asked specifically about screening results for amebiasis, ascariasis, clonorchiasis, giardiasis, hookworm, schistosomiasis, strongyloidiasis, and trichuriasis.

RESULTS

Forty-nine percent of refugees had a reactive tuberculin test of >or=10 mm induration, with a higher prevalence in males (54%) and refugees >or=18 years of age (63%) (p<0.001). Seven percent had a positive hepatitis B surface antigen, with the highest prevalence in those people from sub-Saharan Africa (8%) (p=0.002) and those refugees >or=18 years of age (9%) (p=0.006). Twenty-two percent had one or more intestinal parasites asked about, including 30% of those refugees <18 years of age (p<0.001). The most commonly reported parasitic infections were trichuriasis (8%) and giardiasis (7%).

CONCLUSIONS

Evidence of infection with M. tuberculosis, hepatitis B virus, or one of eight intestinal parasites was present in a substantial proportion of refugees receiving the domestic health assessment. Screening for such infections gives new immigrants the opportunity to receive important medical evaluation and treatment, provides valuable surveillance data, and allows appropriate public health measures to be taken.

Differential genetic determination of immune responsiveness to hepatitis B surface antigen and to hepatitis A virus: a vaccination study in twins

BACKGROUND

The course of viral hepatitis is thought to be affected by genetic host variability and, in particular, by genes of the major histocompatibility locus. Hepatitis A and B vaccination is a useful model to study the effect of host factors on the immune response to viral antigens. We aimed to assess the heritability of the HBsAg (anti-HBs) and anti-hepatitis A virus (anti-HAV) immune response and to estimate the effect of the HLA-DRB1 locus and other genetic loci unlinked to HLA.

METHODS

We did an open prospective study and vaccinated 202 twin pairs with a combined recombinant HBsAg/inactivated hepatitis A vaccine. We measured antibodies to HBsAg and HAV and determined HLA-DRB1* alleles. Heritability was calculated based on variance of antibody response within pairs. Model-fitting analyses were done to analyse genetic and environmental components of vaccine responses.

FINDINGS

Anti-HBs and anti-HAV showed heritabilities of 0.61 (95% CI 0.41 to 0.81) and 0.36 (-0.02 to 0.73), respectively. For the anti-HBs immune response, 60% of the phenotypic variance was explained by additive genetic and 40% by non-shared environmental effects. The heritability of the HBsAg vaccine response accounted for by the DRB1* locus was estimated to be 0.25, leaving the remaining heritability of 0.36 to other gene loci.

INTERPRETATION

Genetic factors have a strong effect on the immune response to HBsAg. Although genes encoded within the MHC are important for this immune response, more than half the heritability is determined outside this complex. Identification of these genes will help us to understand regulation of immune responses to viral proteins.

C4A deficiency and nonresponse to hepatitis B vaccination

BACKGROUND/AIMS

Hepatitis B vaccination failure has been linked to the presence of certain human leukocyte antigen class II alleles. However, the functional background of these associations has remained unclear. Complement component C 4 is encoded within the major histocompatibility complex and is essential for classical pathway activation.

METHODS

Healthy individuals (n=4269) were vaccinated in a prospective trial with Engerix B. Nonresponse was classified as anti-HBs<10 U/l after the last vaccination. Seventy-three nonresponders (NR) (1.7%) were identified. For comparison 53 responders (R) (anti-HBs>10 IU/l) were drawn randomly from the same cohort. C4 allotyping was carried out by high-voltage agarose gel electrophoresis and C4alpha-chain typing using sodium dodecyl sulfate-polyacrylamide gel electrophoresis. C4 gene deletions (C4Del) were studied by Southern blot.

RESULTS

C4AQ0 alleles were observed in 45/73 (62%) NR compared to 17/53 (32%) R (P=0.001). C4ADel was observed in 24/73 (33%) NR and in 6/52 (12%) R (P=0.006). C4AQO alleles were present in 21/49 (43%) NR without C4Del compared to 10/46 (22%) in R without C4Del (P=0.031). In a logistic regression with DRB1*0301, DRB1*07, DRB1*1301 and C4AQ0 all except for DRB1*0301 showed a significant association.

CONCLUSIONS

C4AQ0 shows a DRB1*0301 independent association with vaccine failure. C4AQ0 alleles probably contribute to inefficient complement activation and failure of B cells to secrete anti-HBs.

Compliance with hepatitis B vaccination in 1175 heroin users and risk factors associated with lack of vaccine response

AIMS

To investigate the feasibility of hepatitis B vaccination among heroin users, assessing adherence to the vaccination schedules and identifying factors associated with antibody response.

DESIGN AND PARTICIPANTS

A large cohort study in nine public centres for drug users (PCDUs) in north-eastern Italy, with data collected between January 1989 and December 1998. A total of 1175 heroin users were selected and vaccinated with a recombinant vaccine using two schedules (0-1-6 months and 0-1-2 months).

FINDINGS

Eighty-eight per cent of patients completed the vaccination series and a protective antibody response occurred in 77% of subjects. Completion of the vaccination series was not related to the length of the vaccination schedule or whether the patient was still in drug abuse treatment at the end of the series, but was related strongly to the number of patients enrolled at each PCDU (Spearman correlation = - 0.93, P < 0.001). Four variables were significantly associated with lack of seroconversion in response to vaccination: older age (AOR = 0.91 per year, 95% CI 0.88-0.94, P < 0.001), 2-month vaccination schedule (AOR = 3.10, 95% CI 2.06-4.68, P < 0.001), HCV seropositivity (AOR = 0.69, 95% CI 0.47-0.99, P = 0.04), HIV seropositivity (AOR = 0.27, 95% CI 0.10-0.77, P = 0.01).

CONCLUSIONS

A large-scale, multi-site hepatitis B vaccination programme for heroin users proved feasible and effective. The factors associated with a lack of antibody response may be useful in identifying patients who would benefit most from routine post-vaccination testing, with booster doses for non-responders. These results suggest that hepatitis B vaccination for drug users should become a routine public health practice.

Hepatitis B in Italy: where we are ten years after the introduction of mass vaccination

In Italy, a program of vaccination against hepatitis B targeted at the immunisation of persons at high risk began in 1983. In 1991, vaccination became mandatory for all newborns and adolescents. Since then, the vaccine has been given to more than 10 million children, with an outstanding record of safety and efficacy. The coverage rate is globally around 94%, with differences between the Northern and Southern regions, with the latter having the lower acceptance rate. According to the National Surveillance System (SEIEVA), the incidence of acute hepatitis B per 10(5) inhabitants declined from 5.4 in 1990 to 2 in 2000. The reduction was even greater among 15-24-year-old individuals, where the incidence rate per 10(5) decreased from 17.3 to 2 in the same period. In parallel with the decline of hepatitis B, hepatitis delta has also declined significantly. Catch-up immunisation of unvaccinated adolescents, as well as an effort to improve the vaccination coverage rate in high-risk groups, are required to ameliorate the efficacy of the vaccination campaign. Routine administration of booster doses of vaccine is not considered necessary to sustain immunity in immunocompetent persons.

Seroepidemiology of hepatitis A antibodies among children's hospital staff

BACKGROUND

With improved socioeconomic conditions, adults are more frequently seronegative for hepatitis A virus (HAV) and therefore susceptible to infection. A safe and efficacious active HAV vaccine has been developed and licensed. The general recommendation is to vaccinate populations at increased occupational exposure to HAV.

AIM

To determine the seroprevalence of HAV antibodies among children's hospital employees and to correlate seropositivity with demographic and occupational variables as a basis for formulating vaccine recommendations.

METHODS

The staff of a tertiary pediatric medical center participated by answering a structured questionnaire on demographic and occupational data and by donating venous blood for determining HAV antibodies by an enzyme immunoassay. Univariate and multivariate analyses were conducted to identify variables associated with HAV seropositivity.

RESULTS

HAV antibodies were found in 48.3% of the 499 employees studied, being lowest in pediatricians (38.7%), and increased with years of work at the hospital, job percentage and contact with pediatric patients. However, multivariate analysis showed that only the sociodemographic variables (age and crowding during childhood) were independently and significantly associated with seropositivity.

CONCLUSIONS

HAV seropositivity was associated mainly with sociodemographic variables. Most children's hospital employees, especially pediatricians and other young (<40 years) employees, are seronegative and therefore susceptible to HAV. Vaccination of the high risk groups should be considered.

The antibody response to hepatitis B virus vaccination is negatively influenced by the hepatitis C virus viral load in patients with chronic hepatitis C: a case-control study

The purpose of this work was to evaluate in a case-control study the immunogenicity of a recombinant hepatitis B virus (HBV) vaccine in patients with chronic hepatitis C. Seventy-seven patients with histologically proven chronic hepatitis C without cirrhosis were included in a prospective trial and matched for sex and age to 231 healthy adult subjects. Recombinant HBV vaccine was administered at a dose of 20 microg at months 0, 1 and 2. The definition of 'responder to vaccination' was anti-HBs titre > 10 mIU/ml after the three injections. Forty-nine (63.6%) chronic hepatitis C patients were responders to vaccination, compared with 217 (93.9%) controls (P < 0.0001). After the three injections, anti-HBs titres were 156 +/- 260 and 615 +/- 435 mIU/ml (P < 0.0001), respectively. Chronic hepatitis C patients who were non-responders to vaccination had significantly higher viral load than responders to vaccination. Moreover, a negative correlation was observed between viral load and anti-HBs concentration (r = -0.36, P = 0.003). No significant side effects were observed. There was no effect of vaccination on alanine aminotransferase (ALT) levels and hepatitis C virus (HCV) viral load during or after vaccination. In multivariate analysis, the main predictive factors of response to HBV vaccine were absence of anti-HCV antibodies (OR = 7.65, P < 0.0001), weight < 75 kg (OR = 1.99, P < 0.035), and age < 50 years (OR = 1.58, P < 0.082). Our results suggest that viral load seems to negatively influence the response to HBV vaccine.

Replication of subgenomic hepatitis A virus RNAs expressing firefly luciferase is enhanced by mutations associated with adaptation of virus to growth in cultured cells

Replication of hepatitis A virus (HAV) in cultured cells is inefficient and difficult to study due to its protracted and generally noncytopathic cycle. To gain a better understanding of the mechanisms involved, we constructed a subgenomic HAV replicon by replacing most of the P1 capsid-coding sequence from an infectious cDNA copy of the cell culture-adapted HM175/18f virus genome with sequence encoding firefly luciferase. Replication of this RNA in transfected Huh-7 cells (derived from a human hepatocellular carcinoma) led to increased expression of luciferase relative to that in cells transfected with similar RNA transcripts containing a lethal premature termination mutation in 3D(pol) (RNA polymerase). However, replication could not be confirmed in either FrhK4 cells or BSC-1 cells, cells that are typically used for propagation of HAV. Replication was substantially slower than that observed with replicons derived from other picornaviruses, as the basal luciferase activity produced by translation of input RNA did not begin to increase until 24 to 48 h after transfection. Replication of the RNA was reversibly inhibited by guanidine. The inclusion of VP4 sequence downstream of the viral internal ribosomal entry site had no effect on the basal level of luciferase or subsequent increases in luciferase related to its amplification. Thus, in this system this sequence does not contribute to viral translation or replication, as suggested previously. Amplification of the replicon RNA was profoundly enhanced by the inclusion of P2 (but not 5' noncoding sequence or P3) segment mutations associated with adaptation of wild-type virus to growth in cell culture. These results provide a simple reporter system for monitoring the translation and replication of HAV RNA and show that critical mutations that enhance the growth of virus in cultured cells do so by promoting replication of viral RNA in the absence of encapsidation, packaging, and cellular export of the viral genome.

Binding of hepatitis C virus-like particles derived from infectious clone H77C to defined human cell lines

Hepatitis C virus (HCV) is a leading cause of chronic hepatitis in the world. The study of viral entry and infection has been hampered by the inability to efficiently propagate the virus in cultured cells and the lack of a small-animal model. Recent studies have shown that in insect cells, the HCV structural proteins assemble into HCV-like particles (HCV-LPs) with morphological, biophysical, and antigenic properties similar to those of putative virions isolated from HCV-infected humans. In this study, we used HCV-LPs derived from infectious clone H77C as a tool to examine virus-cell interactions. The binding of partially purified particles to human cell lines was analyzed by fluorescence-activated cell sorting with defined monoclonal antibodies to envelope glycoprotein E2. HCV-LPs demonstrated dose-dependent and saturable binding to defined human lymphoma and hepatoma cell lines but not to mouse cell lines. Binding could be inhibited by monoclonal anti-E2 antibodies, indicating that the HCV-LP-cell interaction was mediated by envelope glycoprotein E2. Binding appeared to be CD81 independent and did not correlate with low-density lipoprotein receptor expression. Heat denaturation of HCV-LPs drastically reduced binding, indicating that the interaction of HCV-LPs with target cells was dependent on the proper conformation of the particles. In conclusion, our data demonstrate that insect cell-derived HCV-LPs bind specifically to defined human cell lines. Since the envelope proteins of HCV-LPs are presumably presented in a virion-like conformation, the binding of HCV-LPs to target cells may allow the study of virus-host cell interactions, including the isolation of HCV receptor candidates and antibody-mediated neutralization of binding.

Estimation of the risk of bloodborne pathogens to health care workers after a needlestick injury in Taiwan

OBJECTIVES

To estimate the number of health care workers (HCWs) in Taiwan at risk annually for contracting hepatitis B virus (HBV), hepatitis C virus (HCV), and HIV after a needlestick and sharps injury (NSI) with a used hollow-bore needle.

METHODS

All patients hospitalized in 1 tertiary hospital between September 1997 and June 1998 had routine pathological work-ups. On the first day of the months of September 1997, December 1997, March 1998, and June 1998, 1805 samples of deidentified residual sera randomly sampled from 18,474 inpatients older than 6 years were serologically tested for antigens to HBV (HBsAg and HBeAg) and antibodies to HCV (anti-HCV) and HIV (anti-HIV) with enzyme-linked immunosorbent assay reagents. The frequency of NSIs with contaminated devices in HCWs from 16 public teaching hospitals between July 1996 and June 1997 and the serologic results were used to extrapolate the estimated annual rate of seroconversion in HCWs after an NSI.

RESULTS

Of the 1805 samples tested, 16.7% were seropositive for HBsAg (of which 1.7% were positive for HBeAg), 12.7% were positive for anti-HCV, and 0.8% were positive for anti-HIV. Of the 7550 NSIs reported by 8645 HCWs, 66.7% involved a contaminated hollow-bore needle. From these data, 308 to 924 HCWs were estimated to be at risk for contracting HBV; 334 to 836 were at risk for contracting HCV; and, at the most, 2 were at risk for contracting HIV. The estimated annual number of contaminated NSIs sustained by 4 categories of HCWs ranged from 0.3 to 0.7, resulting in 543 nurses, 113 technicians, 80 physicians, and 66 supporting staff to be at risk annually of acquiring HBV infection. The numbers of HCWs estimated to be at risk of acquiring HCV were 596 nurses, 90 physicians, 84 technicians, and 30 supporting staff. The risk of acquiring HIV was low, with 1 nurse and possibly 1 other staff potentially exposed annually.

CONCLUSIONS

Our estimates of the risk for seroconversion after an NSI have demonstrated that an occult risk can be formulated into a quantifiable risk. The number of susceptible HCWs at risk for seroconversion is as many as 1762 annually. With the number of nurses employed and the frequency with which they use sharps and sustain an NSI, 64.7% of all possible seroconversions will be in the nursing staff. This is a salient reminder of the importance of the introduction of early training in safe-needle-handling techniques before nurses enter their internship in countries where safety equipment, safety instructions, and staff vaccination programs are absent.

The effect of high dose and short interval HBV vaccination in individuals with chronic hepatitis C

OBJECTIVES

The efficacy of the standard hepatitis B virus (HBV) vaccination schedule in individuals with chronic hepatitis C is reported to be reduced. Our aim was to assess the response rate to high dose, short interval HBV vaccination in such individuals.

METHODS

A total of 152 individuals with chronic hepatitis C were vaccinated with 40 microg of vaccine administered monthly for 3 months. Twenty-six individuals with no evidence of liver disease underwent the same vaccination schedule and were considered to be the control group. Hepatitis C virus (HCV)-positive subjects who did not seroconvert to anti-hepatitis B surface positivity after the third dose of the vaccine (nonresponder) were vaccinated with a fourth dose of vaccine (booster dose, 80 microg).

RESULTS

One hundred nine of the 152 individuals with chronic hepatitis C (72%) seroconverted to anti-hepatitis B surface positivity (> 10 mIU/ml), as compared to 24 of the 26 controls (92%, p < 0.05). Although individuals with chronic hepatitis C responded less frequently to high dose, short interval HBV vaccination than did the controls, no differences in terms of effective immunity (>100 mIU/ml) were evident among the two groups of responders (51% vs 54%). Also, no difference in response was reported between individuals with chronic active hepatitis C and controls (92% vs 80%). The response rate was significantly lower in cirrhotics than in the noncirrhotic group (54% vs 80%, p < 0.001). Besides cirrhosis, no other demographic or bioclinical factor was found to influence the response to vaccination. After the additional booster dose, the overall response was increased to 74% of the cirrhotics and 88% of the noncirrhotics. No major HBV vaccine-related adverse effects were seen.

CONCLUSIONS

A high dose, short interval HBV vaccination schedule is safe in individuals with chronic hepatitis C. From these data, it is suggested that a high dose and a short interval between HBV vaccinations may produce an effective and early antibody response in such patients.

Viral hepatitis in South African healthcare workers at increased risk of occupational exposure to blood-borne viruses

The prevalence of hepatitis A, B and C antibodies was measured in a group of healthcare workers (HCWs) at increased risk of occupational acquisition of blood-borne viruses (N=402) from a large, urban referral hospital in South Africa. The aims of this study were to determine the immunity of HCWs to these agents and to recommend policy for the protection of HCWs against occupational exposure to viral hepatitis in this country. Race, sex and age were shown to be important factors influencing the presence of hepatitis A (HAV) antibodies. Most black HCWs (96.2%) are protected from HAV infection. Females have significantly higher HAV antibodies compared with males and antibodies increase with increasing age. Hepatitis B antibodies (anti-HBs) were found in 30.6% of HCWs. Anti-HBs levels were significantly associated with a past history of HBV vaccination. However, only a small proportion of HCWs (21.2%) could remember ever being immunized against HBV. For those individuals that did receive HBV vaccination (N=83), the mean number of years since their last vaccine was 6.2 years (SD +/- 3.5). HCV antibodies were found in 1.8% of HCWs at increased risk of occupational exposure. It was not possible to define whether these infections were occupationally acquired but genotyping of the HCV (in two of seven cases) showed genotype 5, the predominant South African genotype. New recommendations for the prevention of viral hepatitis in HCWs in South Africa are made, including pre-employment screening for HAV based on self-selection criteria, universal anti-HBs screening with HBV booster vaccination. HCV recommendations are based on appropriate education of HCWs about this infection and its prevention and a standardized post-exposure testing protocol.

Changing scene in hepatitis B serology interpretation

Serological tests have been used in the diagnosis of hepatitis B virus (HBV) infection since the virus was first discovered. Advances in molecular biology and improvements in the understanding of HBV virology have changed the scene of hepatitis B serology interpretation.

Considerations for hepatitis B as part of a combination vaccine

BACKGROUND

In 1991 the Advisory Committee on Immunization Practices (ACIP) developed a comprehensive strategy to eliminate the transmission of hepatitis B virus in the United States, which includes immunization of all infants. Today, as the number of recommended childhood vaccinations increases, combination vaccines are needed to simplify the immunization schedule and improve coverage levels.

METHODS

A review of the literature was performed to determine the considerations that should be taken when hepatitis B virus vaccine (HepB) is included as part of a combination vaccine.

RESULTS

A combination vaccine that incorporates HepB and other routine infant vaccine antigens has been developed for administration at 2, 4 and 6 months of age. Clinical studies have demonstrated that administration of HepB, either as a monovalent or combination vaccine at 2, 4 and 6 months of age, induces a seroprotective immune response similar to that achieved with monovalent HepB administered at 0, 1 and 6 months of age. In addition the combination vaccine results in similar or fewer adverse reactions compared with separate administration of its components. Infants given a dose of monovalent HepB at birth will receive a total of four doses of HepB when the combination is used. The extra dose of HepB has not led to increased adverse reactions.

CONCLUSIONS

A HepB-containing combination vaccine administered at 2, 4 and 6 months of age is as safe and immunogenic as separate administration of its components and will help simplify the childhood immunization schedule.

Hepatitis B virus infected physicians and disclosure of transmission risks to patients: a critical analysis

BACKGROUND

The potential for transmission of blood-borne pathogens such as hepatitis B virus from infected healthcare workers to patients is an important and difficult issue facing healthcare policymakers internationally. Law and policy on the subject is still in its infancy, and subject to a great degree of uncertainty and controversy. Policymakers have made few recommendations regarding the specifics of practice restriction for health care workers who are hepatitis B seropositive. Generally, they have deferred this work to vaguely defined "expert panels" which will have the power to dictate the conditions under which infected health care workers may continue to practice.

DISCUSSION

In this paper we use recent Canadian policy statements as a critical departure point to propose more specific recommendations regarding disclosure of transmission risks in a way that minimizes practice restriction of hepatitis B seropositive health care workers without compromising patient safety. The range of arguments proposed in the literature are critically examined from the perspective of ethical analysis.

SUMMARY

A process for considering the ethical implications of the disclosure of the sero-status of health care workers is advanced that considers the varied perspectives of different stakeholders.

Hepatitis B immunization in postpartum women

OBJECTIVE

To investigate the acceptance and efficacy of hepatitis B immunization in women during the postpartum period.

STUDY DESIGN

A group of 157 consecutive women who were delivered of neonates between 1994 and 1999 under the care of a private, full-time faculty-based practice of obstetrics and gynecology participated in the study. All patients were screened for hepatitis B surface antigen and antibody during their pregnancy. Susceptible patients eligible for hepatitis B immunization were offered the vaccine in the immediate postpartum period. The planned vaccine administration was a series of 3 intramuscular injections, with the second injection given 4 weeks later and the third given 6 months after the initial injection. Rescreening for hepatitis B surface antibody titers was performed at a visit after the last injection. Response to the immunization series was evaluated according to rate of acceptance, compliance, and achievement of seroprotection.

RESULTS

Thirteen (8%) patients had been immunized previously and had antibodies, whereas 8 (5%) patients had serologic evidence of a previous infection. Of the 136 patients eligible for the study, 113 (83%) agreed to participate, 16 (12%) declined, and 7 (5%) moved away from New York right after delivery. Of the 113 participants, 104 (92%) patients received at least 2 vaccine injections, with 80 (71%) completing 3 injections. Among patients who had postvaccinal antibody titers, 66 of 69 (96%) of the group that received 3 injections and 9 (75%) of 12 of the group that received 2 injections were found to have antibodies.

CONCLUSION

Hepatitis B immunization in the postpartum period is feasible and effective.

Characterization of pseudotype VSV possessing HCV envelope proteins

The genome of hepatitis C virus (HCV) encodes two envelope glycoproteins (E1 and E2), which are thought to be responsible for receptor binding and membrane fusion resulting in virus penetration. To investigate cell surface determinants important for HCV infection, we used a recombinant vesicular stomatitis virus (VSV) in which the glycoprotein gene was replaced with a reporter gene encoding green fluorescent protein (GFP) and produced HCV-VSV pseudotypes possessing chimeric HCV E1 or E2 glycoproteins, either individually or together. The infectivity of the pseudotypes was determined by quantifying the number of cells expressing the GFP reporter gene. Pseudotypes that contained both of the chimeric E1 and E2 proteins exhibited 10--20 times higher infectivity on HepG2 cells than the viruses possessing either of the glycoproteins individually. These results indicated that both E1 and E2 envelope proteins are required for maximal infection by HCV. The infectivity of the pseudotype virus was not neutralized by anti-VSV polyclonal antibodies. Bovine lactoferrin specifically inhibited the infection of the pseudotype virus. Treatment of HepG2 cells with Pronase, heparinase, and heparitinase but not with phospholipase C and sodium periodate reduced the infectivity. Therefore, cell surface proteins and some glycosaminoglycans play an important role in binding or entry of HCV into susceptible cells. The pseudotype VSV possessing the chimeric HCV glycoproteins might offer an efficient tool for future research on cellular receptors for HCV and for the development of prophylactics and therapeutics for hepatitis C.

Variations within hepatitis C virus E2 protein and response to interferon treatment

To determine whether the hepatitis C virus (HCV) E2 PePHD sequence (aa 659-670; PKR-eIF2alpha phosphorylation homology domain) is the determinant for the response of interferon treatment, we have analyzed PePHD sequences in HCV-infected patients who had received interferon-alfa treatment. The PePHD sequence from all (6/6) of the patients, who are non- or partial responders to the interferon treatment, is the wild-type sequence (RSELSPLLL-TT, consensus sequence of HCV-1a and HCV-1b). However, there are sequence variations from more than half (5/9) of the patients, who are complete responders to the treatment. We have also analyzed the NS5A ISDR sequence (aa 2209-2248, interferon sensitivity-determining region) variation in HCV-1b-infected patients. No such correlation has been observed. Thus, our data suggest that HCV E2 should play a more important role than NS5A in determining the interferon responses.

Efficient infection of primary tupaia hepatocytes with purified human and woolly monkey hepatitis B virus

The Asian tree shrew, Tupaia belangeri, has been proposed as a novel animal model for studying hepatitis B virus (HBV) infection. Here, we describe a protocol for efficient and reproducible infection of primary tupaia hepatocytes with HBV. We report that human serum interferes with HBV binding to the hepatocytes, thus limiting the maximum multiplicity of infection. Purification of HBV virions by gradient sedimentation greatly enhances virus binding and infectivity. Covalently closed circular DNA was clearly detectable by Southern blot analysis and newly synthesized single-stranded HBV DNA was visible 2 weeks postinoculation. Primary tupaia hepatocytes are also susceptible to infection with the recently discovered woolly monkey hepatitis B virus (WMHBV) but not to woodchuck hepatitis virus infection. Compared to HBV, WMHBV replicated at a higher rate with single-stranded DNA detectable within the first week postinoculation. Primary tupaia hepatocytes should represent a useful system for studying early steps of HBV and WMHBV infection.

Vaccine- and hepatitis B immune globulin-induced escape mutations of hepatitis B virus surface antigen

Hepatitis B virus surface antigen (HBsAg) vaccination has been shown to be effective in preventing hepatitis B virus (HBV) infection. The protection is based on the induction of anti-HBs antibodies against a major cluster of antigenic epitopes of HBsAg, defined as the 'a' determinant region of small HBsAg. Prophylaxis of recurrent HBV infection in patients who have undergone liver transplantation for hepatitis B-related end-stage liver disease is achieved by the administration of hepatitis B immune globulins (HBIg) derived from HBsAg-vaccinated subjects. The anti-HBs-mediated immune pressure on HBV, however, seems to go along with the emergence and/or selection of immune escape HBV mutants that enable viral persistence in spite of adequate antibody titers. These HBsAg escape mutants harbor single or double point mutations that may significantly alter the immunological characteristics of HBsAg. Most escape mutations that influence HBsAg recognition by anti-HBs antibodies are located in the second 'a' determinant loop. Notably, HBsAg with an arginine replacement for glycine at amino acid 145 is considered the quintessential immune escape mutant because it has been isolated consistently in clinical samples of HBIg-treated individuals and vaccinated infants of chronically infected mothers. Direct binding studies with monoclonal antibodies demonstrated a more dramatic impact of this mutation on anti-HBs antibody recognition, compared with other point mutations in this antigenic domain. The clinical and epidemiological significance of these emerging HBsAg mutants will be a matter of research for years to come, especially as data available so far document that these mutants are viable and infectious strains. Strategies for vaccination programs and posttransplantation prophylaxis of recurrent hepatitis need to be developed that may prevent immune escape mutant HBV from spreading and to prevent these strains from becoming dominant during the next decennia.

Persistence of anti-HBs 5 years after the introduction of routine infant and adolescent vaccination in Italy

A population survey was conducted to assess the duration of anti-HBs levels > 10 IU/l in vaccinees living in Lazio Region (Italy) 5 years after the introduction (15 June 1991) of compulsory vaccination of new-borns and 11-year-old children. A random sample of 1192 (533 children born in 1991--92 and 659 adolescents born in 1979--81) was selected. In 92.9% of children and 94.1% of adolescents anti-HBs titres were protective (> or = 10 IU/l). These subjects with protective titres were divided into three categories: low responders (anti-HBs titres = 10--500 IU/l), medium responders (anti-HBs titres = 501--2000 IU/l) and high responders (anti-HBs titres > 2000 IU/l). Factors associated with the level of response were analysed, using a multiple politomic logistic regression analysis. Greater age at first dose (11--12 years) was associated with higher titres (OR = 2.1, 95% CI = 1.4--3.2 for medium responders and OR = 3.0, 95% CI = 1.9--4.8 for high responders). Simultaneous administration of DT vaccine was associated with lower titres (OR = 0.4, 95% CI = 0.2-0.8 for medium responders and OR = 0.3, 95% CI = 0.1--0.7 for high responders).

Hepatitis B vaccination in liver transplant candidates

Liver transplantation has become the treatment of choice for patients with end-stage liver disease. De novo hepatitis B infection after liver transplantation is a rare event and usually runs a mild clinical and histological course. Despite the favourable outcome, a wide spectrum of hepatitis B virus (HBV)-associated liver disease may develop, ranging from asymptomatic carriage to severe chronic active hepatitis or cirrhosis and even fulminant hepatic failure. The achievement of protective titres of anti-HBs through vaccination has been suggested to be protective against the development of de novo HBV infection. The results of vaccination in cirrhotic patients awaiting for liver transplant have been very disappointing. High-dose/short-term schedules have been tried in transplant candidates in order to increase the response rate. New and more immunogenic formulations (containing new adjuvants or additional pre-S1/pre-S2 recombinant antigens), and, more importantly, early vaccination of potential transplant candidates at earlier stages of their liver disease should further prevent de novo hepatitis B in transplant recipients.

The presence of hepatitis A antibodies in dental workers. A seroepidemiologic study

BACKGROUND

The licensing of hepatitis A vaccine in the United States and other countries in the 1990s raised the question of vaccine candidates. The authors undertook a study to evaluate the presence of antibodies against hepatitis A virus, or HAV, in dental workers.

METHODS

The authors recruited 115 members of the dental staff of Tel Aviv University: 82 dentists, 21 dental assistants, eight dental hygienists and four laboratory technicians. The subjects completed a structured questionnaire regarding demographic information (such as age, sex, number of siblings, number of children) and occupational characteristics. Venous blood was obtained and examined for presence of immunoglobulin G antibodies to HAV by microparticle enzyme immunoassay.

RESULTS

Univariant analysis (chi 2 and Student t test) and multivariate stepwise logistic regression analysis were used to identify variables that were associated with seropositivity. Greater number of years of occupation in dentistry were independently and significantly (P = .0004) associated with seropositivity to HAV. The calculated odds ratio showed that each year of work increased the likelihood of being seropositive by 1.06 (6 percent). Subjects tended to have higher seropositive rates if they were older, had a greater number of children, had a greater number of siblings, had worked in hospitals and worked with children (pediatric dentists and orthodontists).

CONCLUSIONS

This study suggests that HAV can be considered a hazard to dental workers, with risk increasing as the number of years in dentistry increases. More studies with larger sample sizes are needed.

CLINICAL IMPLICATIONS

As HAV infection is associated with morbidity and mortality, dentists--especially those working in areas of endemic HAV (such as Africa, Asia and Latin America)--are encouraged to consider receiving the active vaccine to prevent HAV infection.

Update on hepatitis B vaccination in Italy 10 years after its implementation

Since the beginning of the Italian program of immunization against hepatitis B, vaccine has been given to more than 9 million children, with an outstanding record of safety and efficacy. The coverage rate is globally around 94%, with differences between Northern and Southern regions, the latter having the lower acceptance rate. According to the National Surveillance System (SEIEVA), the incidence of acute hepatitis B per10(5) inhabitants declined from 5.4 in 1990 to 2.9 in 1998. The reduction was even greater among 15-24-year-old individuals, where the incidence rate per 10(5) decreased from 17.3 to 4.2 in the same period. In parallel with the decline of hepatitis B, Delta hepatitis has also dropped significantly. We expect that by the year 2003 (12 years after the beginning of the program) this vaccination strategy will have led to the protection of all Italians aged 0-24 years, who are those at the higher risk for acquiring hepatitis B virus (HBV) and for developing the chronic carrier state.

Induction of virus-specific cytotoxic T lymphocytes by in vivo electric administration of peptides

Generally, major histocompatibility complex (MHC) class I presentation of peptide antigens only occur for proteins' which are actively synthesized and processed intracellularly, so that immunization with a cytotoxic T lymphocyte (CTL) target peptide does not usually elicit effective CTL responses. In the present study, we explored the use of epitope peptides by in vivo electroporation to introduce directly into the cytoplasm for the vaccine elicitation of virus-specific CTLs in a mouse system. BALB/c mice were immunized with human immunodeficiency virus (HIV) env (P18, residues 311-320) or hepatitis C virus (HCV) NS5 (P17, residues 2423-2434) with or without electric pulses. Effector cells against peptide-labeled target cells were elicited in mice immunized with peptides with electric administration but not without electric administration. Moreover, cytolytic activities of CTL against peptide-labeled target cells were enhanced by the addition of plasmid having the immunostimulatory sequence (ISS) or cDNA of the B7-1 molecule in electric administration of peptides. The results of the present study suggest that a peptide vaccine against a virus using electric administration is effective in eliciting virus specific CTLs.

Change in hepatitis A virus seroepidemiology in southern Taiwan: a large percentage of the population lack protective antibody

Hepatitis A, the predominant reported etiologic form of viral hepatitis in Taiwan, continues to be a disease primarily of children and young adults. A seroepidemiologic study was performed to assess the seroprevalence of hepatitis A (HAV) antibodies in the southern Taiwan general population in 1998 and is compared with results of a similar study in 1992. A total of 948 subjects (477 male and 471 female) with ages ranging from 0.3 to 63 years were stratified into 14 age-specific groups. The presence of anti-HAV antibodies was detected using a commercially available radioimmunoassay. Fifteen percent of the subjects were positive for anti-HAV antibodies, which is lower than that in 1992 (P < 0.001). Seroprevalences were 14.1% for males and 22.6% for females (P = 0.006). The pattern of anti-HAV seroprevalence was distinguishable from that found in 1992; minimum seroconversion occurred at ages ranging from 1 to 30 years. Prevalence of seropositive subjects decreased markedly for the < 1, 13-15, 16-19, 20-24, 25-29, and 30-39 year age groups in comparing 1998 with 1992. The current study demonstrates a continuing decline in the prevalence of HAV among children, adolescents, and young adults. The findings can be ascribed to the improvement of socioeconomic status and modernization of environmental sanitation. As a consequence of this changing trend of endemicity and the resulting lack hepatitis A antibodies among the general population in Taiwan, the risk of sudden major outbreaks is increased because of increasing international travel and immigration, particularly during and after natural disasters. HAV vaccination will be important for the prevention and control of HAV outbreaks in the community.

Cost-benefit analysis of a nationwide infant immunization programme against hepatitis A in an area of intermediate endemicity

BACKGROUND/AIMS

The availability of safe and effective Hepatitis A vaccines prompts an evaluation of a nationwide infant vaccination campaign to supplement strategies aimed at high-risk groups such as travellers and military personnel.

METHODS

A spreadsheet model was used to estimate costs and benefits of a nationwide infant immunization programme against Hepatitis A for the period from 1997-2014 in Israel.

RESULTS

Immunizing all one year olds in Israel from 1997-2014 would for a cost of $32.0 million to the health services and $42.1 million to society (including $10.1 million lost work and transport costs), reduce the number of cases of Hepatitis A during the next 45 years from 181,000 to 47,000. This would save $57.5 million in health service resources alone, $32.0 million in averted work absences and transport costs in addition to a further $17.0 million in averted premature mortality costs. The health service, resource and societal benefit:cost ratios are 1.80:1, 2.13:1 and 2.54:1, respectively.

CONCLUSIONS

The recent adoption of a nationwide infant HAV immunisation policy in Israel is both medically and economically justifiable.

Health care workers

More people are employed in the health care sector than in any other industry in the United States. Health care workers are exposed to a wide variety of hazards, including biological, chemical, physical and psychological stressors. Concerns about exposure to contagious diseases such as HIV, Hepatitis B and C, and tuberculosis have influenced the career choices of many health professionals. Physical hazards, especially ergonomic ones, account for the majority of the disability faced by health care workers. Chemical exposure and psychosocial stresses are also present in health care institutions. The exposure encountered in health care facilities is potentially dangerous to health care workers as well as to their family members and unborn children.

Randomized, cross-over, controlled comparison of two inactivated hepatitis A vaccines

The immunogenicity, tolerability and interchangeability of two hepatitis A vaccines, Vaqta (Merck and Co.) and Havrix (SmithKline) were studied in a randomized, crossover, controlled clinical trial. Vaccine was administered to 201 volunteers at 0 and 26 weeks in one of four vaccine regimens: Havrix-Havrix; Havrix-Vaqta; Vaqta-Havrix or Vaqta-Vaqta. Seroconversion rates (>/=10 mIU/ml) for those whose first dose was Vaqta or Havrix, respectively, were: 41/96 (43%) versus 30/95 (32%) (P=0.15) at 2 weeks and 91/98 (93%) versus 84/97 (87%) (P=0.43) at 4 weeks, and 100% at 26 weeks. Geometric mean concentrations (GMC) of total antibody to hepatitis A virus (anti-HAV) for Vaqta and Havrix were 189 and 114 mIU/ml (P=0.011) at 4 weeks and 234 and 136 mIU/ml (P<0.001) at 26 weeks. At 30 weeks, the GMC after two doses of Havrix was 2612 mIU/ml compared with 5497 after two doses of Vaqta (P<0.001). The GMC in the Havrix-Vaqta group was 5672 mIU/ml compared with 3077 mIU/ml in the Vaqta-Havrix group (P<0.001). Less than half of vaccine recipients reported tenderness or pain. In this study, seroconversion rates of the two vaccines were similar. Vaqta produces significantly higher anti-HAV antibody than Havrix. Crossover immunization is well tolerated and results in high antibody concentrations, especially when Vaqta is the booster dose. The significance of higher anti-HAV antibody concentrations in terms of long-term protection is unknown.

Long term persistence of anti-HBs protective levels in young patients with type 1 diabetes after recombinant hepatitis B vaccine

The aim of the present study was to evaluate the persistence of anti-hepatitis B protective levels in young patients with type 1 diabetes, successfully immunised with a recombinant hepatitis B vaccine. We re-evaluated, after a 4 year follow-up, 54 patients and 70 age and sex-matched healthy subjects. Protective antibodies levels were found in 50/54 (92%) patients and in 67/70 (96%) controls. Moreover, anti-HBs levels were similar in diabetic patients and controls (means of log-titre and (sd); 1.95 (0.88) and 2.18 (0.64) patients and controls, respectively; P=0.11). No cases of clinical hepatitis were reported and all patients and controls remained HBc negative. These data demonstrate the persistence of anti-HBs levels in children, adolescents and young patients with type 1 diabetes after recombinant hepatitis B vaccine showing evidence of longterm immunogenity and protective effect.