Epidemiology and prophylaxis of viral hepatitis: a global perspective

Clinical experience with the inactivated hepatitis A vaccine, Avaxim 80U Pediatric

INTRODUCTION

Hepatitis A, caused by hepatitis A virus (HAV), is primarily transmitted via the fecal/oral route either through ingestion of contaminated food and water or through direct contact with an infectious person. Prevalence of hepatitis A is strongly correlated with socioeconomic factors, decreasing with increased socio-economic development, access to clean water and sanitation. Vaccination against HAV should be part of a comprehensive plan for the prevention and control of viral hepatitis, either as part of regular childhood immunization programs or with other recommended vaccines for travelers. Areas covered: We present here evidence for the immunogenicity and safety of an inactivated HAV pediatric vaccine (Avaxim® 80U Pediatric, Sanofi Pasteur), indicated for use in children aged 12 months to 15 years. Data evaluated are from trials undertaken during the clinical development of this vaccine, a systematic literature review and post-market pharmacovigilance. Expert opinion: The pediatric HAV vaccine is highly immunogenic and generates long-lasting protection against hepatitis A disease in children. The safety and immunogenicity data presented in this review suggest that the pediatric HAV vaccine is a valuable option in the prevention of HAV infection in children in many areas of the world where the disease remains a healthcare issue.

Vaccination Against Hepatitis A for Hemophilic Patients: Is It Necessary?

BACKGROUND

Hemophilic patients require long-life intravenous infusion of factor concentrates to treat bleedings. This could increase the risk of transmission of blood-borne infections like hepatitis C.

OBJECTIVES

The current study was aimed at investigating the immunity status against hepatitis A in hemophilic patients in south Khorasan and evaluating the necessity of hepatitis A vaccination for this population.

PATIENTS AND METHODS

A cross-sectional descriptive study was conducted between 2014 and 2015 on all hemophilic patients of south Khorasan province, Iran (n = 108) for anti-HAV total, anti- HCV, HBs-Ag, anti-HIV, and anti-HTLV-I /II. Note that no one had already received a hepatitis A vaccine.

RESULTS

As our results show, 77.8% of the participants (59% under 20 and 88.4% above 20 years old) were seropositive for anti-HAV total; 20.4% and 2.8% (three patients) of the cases were anti-HCV positive and anti-HTLV-1 positive, respectively, while none of the subjects were HBS-Ag or HIV-Ab positive. Seventeen of the patients (15.75%) showed a co-infection of HAV with HCV, and five HCV-infected patients (22.73%) had no immunity against hepatitis A. There was a significant relationship between age, rural life, and anti-HAV positive state in our patients (P < 0.001). No significant relationship between positive anti-HAV status and sex (P = 0.16), severity of hemophilia (P = 0.23), and infection with HIV, HCV, HTLV-1, and hepatitis B (P > 0.05) was detected.

CONCLUSIONS

More than 40% of the hemophilic patients under 20 years of age in the present study had no immunity against hepatitis A, and 23% of hepatitis C patients had not had a hepatitis A co-infection yet. Since hepatitis A can show a fulminant course in hepatitis C patients, vaccination against hepatitis A seems necessary in hemophilic patients in the region.

Window period of anti-hepatitis A virus immunoglobulin M antibodies in diagnosing acute hepatitis A

BACKGROUND

The diagnosis of acute hepatitis A virus (HAV) infection is made on the basis of the presence of anti-HAV immunoglobulin M (IgM) antibodies in patients with clinical features of acute hepatitis. Some patients show a negative serology at initial presentation, which may complicate the diagnosis of hepatitis A (HA). The aim of this study was to examine the characteristics of HA patients with an initially negative anti-HAV IgM test result.

MATERIALS AND METHODS

Patients with symptomatic acute hepatitis who underwent IgM anti-HAV testing at a single center were enrolled consecutively, with tests repeated in patients with negative initial serology.

RESULTS

A total of 684 patients with acute hepatitis were tested, of whom 620 patients were initially or eventually diagnosed with HA. Anti-HAV IgM was initially negative in 67 of the 620 HA patients (10.9%), but was later confirmed by subsequent retests. These patients had on average a shorter time lapse from the onset of symptoms to the initial test, a higher rate of fever, and lower alanine aminotransferase and bilirubin levels compared with those with a positive initial serology. Cutoff index (COI) values of anti-HAV IgM were correlated positively with the duration of time from the onset of symptoms to the initial test. Fever, lower bilirubin levels, and higher COI values were predictive of seroconversion to anti-HAV positivity in patients with a negative initial serology.

CONCLUSION

Taking into account the window period of HAV infection, anti-HAV IgM tests should be repeated, particularly in patients with features of the initial phase of hepatitis and a high COI value of anti-HAV IgM.

New insights into hepatitis C virus infection in the tribal-dominant part of Northeast India

Northeast India is known for the demographic heterogeneity of its tribal population, but there is no information about hepatitis C virus infection and associated risk factors. Anti-HCV was measured, HCV-RNA was detected based on the 5' UTR-core region, and genotyping was done by direct sequencing of the NS5b region. Antibodies to HCV were found in 13.7 % of the samples tested (96 out of 700), while HCV-RNA was positive in 73 % of the samples (70 out of 96) and in 5 out of 385 cases of occult HCV infection. Genotypes 1 to 4 were found respectively in 14.6, 7.3, 20, 30.8 %, and genotype 6 in 13.6 %, of the 75 HCV isolates. In acute viral hepatitis (AVH), the most prevalent genotype was 2a (28.6 %), while it was 4a (28 %) in chronic hepatitis C (CHC) and 29.4 % in cirrhosis. Males were more prone than females to HCV infection, and the highest numbers of cases of HCV infection were recorded in the age group of 40-49 years. The major risk factors were intravenous drug abuse (IVDU) (34.6 %), multiple sexual partners (20 %) and contact with professional barbers (38.6 %). The seroprevalence of HCV in Northeast India is higher than in the rest of India. This study highlights the fact that geographical variations occur with respect to HCV genotypes, which could influence the course and progress of different type of liver diseases seen in India.

Urbanisation and infectious diseases in a globalised world

The world is becoming urban. The UN predicts that the world's urban population will almost double from 3·3 billion in 2007 to 6·3 billion in 2050. Most of this increase will be in developing countries. Exponential urban growth is having a profound effect on global health. Because of international travel and migration, cities are becoming important hubs for the transmission of infectious diseases, as shown by recent pandemics. Physicians in urban environments in developing and developed countries need to be aware of the changes in infectious diseases associated with urbanisation. Furthermore, health should be a major consideration in town planning to ensure urbanisation works to reduce the burden of infectious diseases in the future.

Progressive decrease of hepatitis B in a cohort of drug users followed over a period of 15 years: The impact of anti-HBV vaccination

In the Western world, the population at the highest risk of HBV infection is probably that of illicit drug users (DUs). Since 1985, 1 Public Health Centre for Drug Users (PHCDU), in north-eastern Italy, has been asking all heroin DUs, whether in treatment or not, to undergo screening for HIV, HBV and, since 1989, for HCV infection. Since 1988 the Centre has proposed HBV vaccination to all patients who were negative for all HBV markers. From 1985 to 2001 895 heroin DUs were screened, 726 males and 169 females. 442 (49.4%) were negative to HBV markers at the first control and 72.4% received at least 1 dose of the vaccine. 320 DUs were vaccinated and a total of 995 doses of recombinant vaccine were administered. The anti-HBc antibody appeared in 2 vaccinated patients out of 258 DUs undergoing controls, while 13 seroconversions for anti-HBc occurred in 45 DUs who had refused to be vaccinated. On the basis of these results, HBV vaccination of DUs can be strongly recommended. Vaccination showed a good adherence in a population difficult to treat and can have a leading role in reducing HBV infection in DUs and their contacts.

Bloodborne viral hepatitis infections among drug users: the role of vaccination

Drug use is a prevalent world-wide phenomenon and hepatitis virus infections are traditionally a major health problem among drug users (DUs). HBV and HCV, and to a lesser extent HAV, are easily transmitted through exposure to infected blood and body fluids. Viral hepatitis is not inevitable for DUs. Licensed vaccines are available for hepatitis A and hepatitis B. The purpose of this overview is to show some epidemiological data about HBV and the other blood-borne viral hepatitis among DUs and to summarize and discuss use of hepatitis vaccinations in this population. Successful vaccination campaigns among DUs are feasible and well described. We try to focus on the most significant results achieved in successful vaccination programs as reported in scientific literature. Vaccination campaigns among DUs represent a highly effective form of health education and they are cost-saving.

Análise de fatores associados à não aceitação da vacina contra hepatite B em adolescentes escolares de baixa renda

Para avaliar os fatores de predição da não adesão à vacina contra o vírus da hepatite B (VHB) em adolescentes escolares de baixa renda da Região Metropolitana de Goiânia, Goiás, 304 indivíduos suscetíveis ao VHB, matriculados em duas escolas, foram entrevistados e a vacina contra hepatite foi oferecida. Somente 195 (64%) adolescentes aceitaram a primeira dose da vacina. Por outro lado, 182/195 (93,3%) receberam o esquema completo. Verificou-se que fatores escolares exerceram um papel na aceitação da vacina, uma vez que a escola B e turno noturno foram independentemente associados à não adesão à vacina. Os achados deste estudo ratificam a baixa aceitação da vacina contra hepatite B em adolescentes e evidenciam a necessidade de programas de educação em saúde para sensibilização desse grupo em relação à vacinação, e reforçam a importância de estratégias de imunização na escola para o cumprimento do esquema completo da vacina contra o VHB nesta população-alvo.

Prevalence of hepatitis A virus infection among municipal solid-waste workers

A study was conducted among 151 municipal workers (72 solid-waste workers, and 79 workers not exposed to waste). Total antibodies against Hepatitis A virus (HAV) were measured, and socio-demographic information was collected using a self-administered questionnaire. Univariate analysis has shown that occupational exposure to waste, age, duration of employment and educational status were significantly associated with the prevalence of anti-HAV(+). Municipal Solid Waste Workers had a higher prevalence of anti-HAV(+) in comparison with municipal workers not exposed to waste. Duration of employment was significantly associated anti-HAV(+). Multivariate analysis revealed an independent association of anti-HAV(+) with occupational exposure to waste and ageing. Our results suggest a potential causal role of occupational exposure to waste, in the development of HAV infection.

Prevention of hepatitis A by Havrix: a review

Hepatitis A is one of the most common vaccine-preventable infectious diseases in the world. With at least 1.5 million cases of hepatitis A worldwide each year, disease management constitutes a substantial economic burden. The first effective vaccine against hepatitis A, Havrix was introduced in 1992. This review summarizes data accumulated following more than a decade of clinical experience with this vaccine and compares clinical data with other currently available hepatitis A vaccines. Based on this data and on the current immunological knowledge, a recent consensus concluded that hepatitis A vaccines induce lifelong protection, and thus booster vaccinations against hepatitis A are unnecessary in fully immunized, healthy people. In view of this, current regulatory recommendations for the use of hepatitis A vaccines are reviewed and possible future strategies identified.

Hepatitis A Virus Infections in Travelers, 1988-2004

BACKGROUND

Uncertainty exists about the current risk of hepatitis A virus infection in nonimmune travelers to destinations with high or intermediate risk of transmission. We analyzed recent epidemiological data on imported hepatitis A to determine region-specific attack rates and incidences.

METHODS

Surveillance data on hepatitis A virus infections diagnosed during 1988-2004 were evaluated on the basis of notification by laboratories, additional reports of physicians, and traveler's statistics. This study focuses on international travelers with hepatitis A virus infection detected after their return to Switzerland.

RESULTS

The rate of imported hepatitis A virus infections decreased 75% from 1988 to 2004 and accounted overall for 42% of all hepatitis A cases reported in Switzerland. The actual incidence of hepatitis A in travelers to countries of high or intermediate risk of transmission was 3.0-11.0 per 100,000 person-months abroad for all travelers and 6.0-28.0 per 100,000 for those presumed to be nonimmune. The actual proportion of those visiting friends and relatives among patients with hepatitis A has increased to 28.2%, with children aged 0-14 years predominating. Reductions in the incidence by hepatitis A vaccination were estimated to vary between 35.0% and 61.8% for different destinations.

CONCLUSIONS

The risk of hepatitis A virus infections has decreased by a factor of 10-50-fold over time, compared with findings from older studies. The risk, however, remains very considerable at many destinations, including frequently visited places, such as Mexico. Children of immigrants are a high-risk population. Strategies are needed to reach those at highest risk.

Synthesis and in vitro anti-hepatitis B and C virus activities of ring-expanded ('fat') nucleobase analogues containing the imidazo[4,5-e][1,3]diazepine-4,8-dione ring system

As part of our structure-activity relationship studies, we report here the synthesis and in vitro anti-HBV and anti-HCV activities of a number of ring-expanded ('fat') nucleobases containing the imidazo[4,5-e][1,3]diazepine-4,8-dione ring system. One of the compounds, ZP-88, exhibited a good activity/toxicity profile against HBV by inhibition of the synthesis of extracellular virion release (EC(50)=1.7microM, CC(50)=286microM, SI=168) and intracellular HBV replication intermediates (EC(50)=8.4microM, CC(50)=286microM, SI=34) in cultured human hepatoblastoma 2.2.15 cells. By contrast, most of the compounds tested against HCV had only marginal activity/toxicity profile, although that was still better than that of the reference compound ribavirin.

Hepatite B em gestantes atendidas pelo Programa do Pré-Natal da Secretaria Municipal de Saúde de Ribeirão Preto, Brasil: prevalência da infecção e cuidados prestados aos recém-nascidos

OBJETIVO: Estimar a prevalência do antígeno de superfície do vírus da hepatite B (HBsAg) entre as gestantes atendidas pelo Programa do Pré-Natal da Secretaria Municipal de Saúde de Ribeirão Preto, Brasil, e avaliar os cuidados prestados no pós-parto imediato aos recém-nascidos filhos de mães portadoras deste antígeno. MÉTODOS: Foi realizado um estudo descritivo com 5.191 gestantes atendidas na rotina do pré-natal, através de dados provenientes do Laboratório Municipal de Patologia Clínica de Ribeirão Preto. As gestantes detectadas como portadoras do HBsAg tiveram o parto avaliado em termos da realização dos procedimentos preconizados de imunoprofilaxia para a hepatite B em recém nascidos (aplicação de vacina e de imunoglobulina). RESULTADOS: Foi encontrada uma prevalência de 0,5% (IC 95%: 0,3 - 0,7) de portadoras do HBsAg. Em 66,6 % dos partos de recém-nascidos de mães portadoras do antígeno foram realizados os procedimentos de imunoprofilaxia preconizados. A conduta foi inadequada em 25,0 % dos partos e não pôde ter a sua adequação definida nos 8,4% restantes. CONCLUSÕES: O grupo de gestantes estudado apresentou baixa endemicidade ao vírus da hepatite B. Embora com cobertura de 100% das gestantes atendidas, o screening para hepatite B não tem garantido assistência ideal aos recém-nascidos no que diz respeito à prevenção da transmissão vertical da doença.

Molecular epidemiology of HCV infection among acute and chronic liver disease patients in Kolkata, India

BACKGROUND

In recent years, hepatitis C virus (HCV) infection is gaining importance in Asian countries. Recent studies conducted in different parts of the world revealed that there is a genotypic correlation of disease severity and treatment outcome.

OBJECTIVES

A detailed study was carried out to delineate the genotypic distribution of HCV among acute and chronic liver disease patients in Kolkata, a city in eastern India.

STUDY DESIGN

Acute and chronic liver disease was diagnosed among patients attending hepatitis clinics in the city. Anti-HCV ELISA was performed on the blood samples of the cases and positive samples were tested for presence of HCV-RNA and genotyping of the samples were carried out by reverse transcription and polymerase chain reaction (RT-PCR) and sequencing.

RESULTS

Seroprevalence of HCV infection among acute (11.0%) and chronic (25.3%) hepatitis patients were high and among them 97 (75.8%) and 323 (86.1%) were HCV-RNA positive for acute and chronic hepatitis patients, respectively. Genotyping by PCR showed that the predominant genotype was 3b (42.3%) followed by 3a (28.9%) among acute hepatitis group whereas among chronic hepatitis group, the most prevalent genotypes were 3a (34.7%) and 3b (47.7%). Sequence analysis of the untypeable isolates revealed the presence of a rare subtype 6b.

CONCLUSIONS

The study revealed very high prevalence of HCV among acute and chronic hepatitis patients with predominance of genotype 3. Subtype 6b was commonly found in Thailand but not in India. The detection of this rare strain of Thai origin reveals the spread of HCV infection from Thailand to other parts of Asia. This observation necessitates further intensive surveillance of HCV infection in India to unravel the distribution of genotypes in the country and to correlate disease severity and treatment outcome to the genotype prevalence.

Clinical features and molecular characterization of hepatitis A virus outbreak in a child care center in Thailand

BACKGROUND

As a result of declining hepatitis A endemicity in Thailand, an increasing number of children and adolescents have become susceptible to hepatitis A virus (HAV) infection.

OBJECTIVE

The present study was aimed at both investigating the clinical features and determining molecular characterization of HAV during an outbreak, which occurred in a childcare center located in a suburban area of Bangkok between November 2002 and February 2003.

METHODS

Serum samples obtained from all children in the center were tested for anti-HAV IgG and anti-HAV IgM. Testing for HAV-RNA was performed in sera, saliva and stool samples by the reverse transcription-polymerase chain reaction (RT-PCR) with primers located at the VP1-2A region. To further characterize the HAV genotype serum derived HAV-RNA-positive PCR products were sequenced.

RESULTS

Anti-HAV IgG and anti-HAV IgM were detected in 74 and 70 of 112 children in the center, respectively. Among those positive for anti-HAV IgM, 65 cases were asymptomatic, while five children had acute clinical hepatitis. The ratio between symptomatic and asymptomatic children was 1:13. Among the asymptomatic cases, 31 (47.7%) displayed biochemical hepatitis with elevated alanine aminotransferase (ALT) levels. All the isolates from this outbreak were found to be of subgenotype IA, which showed a high level of sequence homology with previous Thai isolates. HAV-RNA could not be detected in saliva, but was found in stool for at least 3 weeks after initial diagnosis of clinical or biochemical hepatitis.

CONCLUSION

Because of the infection's characteristically asymptomatic spread, hepatitis A poses an increased risk to childcare centers. The presence of a single sub-genotype indicates that this HAV strain has been predominantly circulating in Thailand.

Immunogenicity, reactogenicity and adherence to a combined hepatitis A and B vaccine in illicit drug users

AIMS

The use of illegal drugs is associated with an increase in infective risk for the hepatitis viruses, against which the vaccination of drug users (DUs) is recommended unanimously. The aim of the study was to determine tolerability, adherence and immune response of a combined vaccine providing dual protection against hepatitis A virus (HAV) and hepatitis B virus (HBV).

METHODS

The vaccine was administered to 38 DU, attending three public health centres for drug users in northern Italy, with a three-dose schedule (at 0, 1 and 6 months). The vaccine was well tolerated: only one adverse reaction (fever) was recorded after the 110 doses administered (0.9%). The vaccine schedule was completed successfully in 35 cases (92.1%). At month 8, in 34 subjects (89.5%) antibody response was evaluated: all showed seroprotection for HAV and in 33 subjects (97.1%) for HBV.

CONCLUSIONS

The vaccine, studied for the first time in DUs, proved to be safe, well accepted and immunogenic; anti-HAV response was 1272 mIU/ml and 1726 mIU/ml for anti-HBV, titres lower than reported in literature for the general population. This study suggests that DUs who are HAV/HBV-negative could be vaccinated with combined vaccine.

Bacteria as DNA vaccine carriers for genetic immunization

Genetic immunization with plasmid DNA vaccines has proven to be a promising tool in conferring protective immunity in various experimental animal models of infectious diseases or tumors. Recent research focuses on the use of bacteria, in particular enteroinvasive species, as effective carriers for DNA vaccines. Attenuated strains of Shigella flexneri, Salmonella spp., Yersinia enterocolitica or Listeria monocytogenes have shown to be attractive candidates to target DNA vaccines to immunological inductive sites at mucosal surfaces. This review summarizes recent progress in bacteria-mediated delivery of plasmid DNA vaccines in the field of infectious diseases and cancer.

Development and application of a mixed microarray in detection of genes of HBV and HCV

AIM: To develop a DNA microarray to detect hepatitis virus B (HBV) DNA, hepatitis virus C (HCV) RNA, HBV YMDD mutant and HCV genotype simultaneously. At the same time, the chip was compared with other techniques to evaluate its prospect in clinical application.

METHODS: A set of probes was designed to detect HBV DNA, HCV RNA, HBV YMDD mutant and HCV genotype. The probes were synthesized by DNA synthesizer. The microarray was prepared by spotting the probes onto the specially treated glass sliders. Serum samples were collected from inpatients and outpatients at the Department of Infectious Diseases, the Third Affiliated Hospital of Zhongshan University. Among the samples, 20 were comfirmed HBV DNA positive by fluorescent quantitation PCR, 20 were HCV RNA positive, 20 were comfirmed YMDD mutant by mismatched PCR, 10 were HBV DNA and HCV RNA negative. HBV DNA and HCV RNA were extracted from the serum, then amplified by asymmetric PCR or RT-PCR in the presence of sense fluorescein labeled primers. The products of HBV YMDD and HCV NS-5 were purified and sequenced. Following the hybridization of amplified products on the microarrays, detection was carried out by the fluorescence scanner. The detection results were obtained by analyzing the intensity and ratio of the fluorescence signals using image analysis software.

RESULTS: For the HBV DNA positive samples and HCV RNA positive samples, an intensive signal was observed at the point of corresponding probes on the microarrays. In detection of YMDD mutant, the coincident rate of the microarray and the mismatched PCR was 75%, the coincident rate of microarray and sequencing was 95%. In detection of HCV genotype, the coincident rate of microarray and sequencing was 75%.

CONCLUSION: The technology of microarray appears to be versatile, with a great sensitivity and specifity in detection of HBV and HCV. Furthermore, it can find co-infection of different virus strains. But it has some false negative rate and false positive rate in HCV genotyping.

Hepatitis B and C in the hemodialysis unit of Tocantins, Brazil: serological and molecular profiles

A survey was conducted in the hemodialysis population of the state of Tocantins, Brazil, aiming to assess the prevalence of hepatitis B virus (HBV) and hepatitis C virus (HCV) infections, to analyze associated risk factors, and also to investigate these viruses genotypes distribution. During January and March 2001, all patients (n = 100) were interviewed at the unique dialysis unit in Tocantins. Blood samples were collected and serum samples were screened for HBV serological markers. Hepatitis B surface antigen positive samples were tested for HBV DNA. All samples were also tested for anti-HCV antibodies and HCV RNA. An overall prevalence of 45% was found for HBV infection (4% were HBsAg/anti-HBc positive, 2% were anti-HBc only and 39% had anti-HBc/anti-HBs markers). Concerning HCV infection, anti-HCV and HCV RNA were detected in 13% and 14% of the subjects, respectively. Three patients were HCV RNA positive and anti-HCV negative, resulting in an overall HCV prevalence of 16%. Univariate analysis of risk factors showed that only shift and length of tile on hemodialysis were associated with HBV and HCV positivity respectively. Among the four HBsAg-positive samples, HBV DNA was detected in three of them, which were identified as genotype A by restriction fragment length polymorphism (RFLP) analysis. All 14HCV RNA-positive samples were genotyped by INNO-LiPA. Genotypes la and 3a were found in 85% and 15%, respectively. The present data show low HBsAg and HCV prevalence rates. The risk factors associated with HBV and HCV positivity suggest that nosocomial transmission may influence in spreading these viruses in the dialysis unit studied.

Pathophysiology of Hepatitis C and HIV Coinfection

Hepatitis C infection is the most common cause of chronic hepatitis that can lead to cirrhosis and hepatocellular cancer. Hepatitis C virus infects approximately 70 million people worldwide. Hepatitis C is usually transmitted by injection drug use and blood transfusion. Hepatitis C is prevalent in HIV-infected individuals. Coinfection complicates the treatment of these two distinct viral infections. Understanding the normal functions of the liver and the pathophysiological effects of coinfection enables health care professionals to provide the highest level of care for these individuals.

Long-term immunogenicity and protective efficacy of a live attenuated hepatitis A vaccine (LA-1 strain)

AIM

To evaluate the long-term protective efficacy following a large scale immunization with a live attenuated hepatitis A vaccine (the LA-1 strain) and immune persistence of the vaccine with different immunization schedules.

METHODS

A randomized controlled double-blind study was conducted in 212 985 children between 1.5 and 10 years of age from 8 counties in Guangxi province (10 0735 in vaccine group and 112 250 in control group). Vaccine group was received one dose of HAV vaccine of 10^6.75 TCID₅₀ (LA-1 strain, China). Surveillance of the incidence of hepatitis A in the two groups was started 1 month after vaccination. To evaluate the persistence of antibodies, 156 children of 6-9 years old with hepatitis A antibody negative were divided into 3 groups with equalities in age and sex. Group A was given one dose of the vaccine, Group B and C were immunized according to 0, 6 and 0, 12 schedules respectively. During follow-up of every individual, the blood specimens were collected at 6, 12, 24 and 36 months after immunization in Group A and 12, 24 and 36 months after first dose and 1 month after second dose in Group B and C. Anti-HAV levels were expressed as GMTs in mIU/ml by serial immunoglobulin dilutions (WHO standard) and HAVAB-Imx kit (Abbott Lab, USA).

RESULTS

During a follow-up for 36 months, 71 cases of symptomatic HAV infection were found in the control and 2 in the vaccine group (63.25/10⁶vs 1.99/10⁶ respectively). The protective efficacy was estimated at 96.85% with 95% lower confidence limit of 92.4%. The antibody positive rate in Group A after 6-24 months was 88.6-91.4%, the GMT was 105-106 mIU/ml, but each of those decreased to 80.0% and 99.20 mIU/ml after 36 months. GMT reached to the top in Group B and C1 month after the second dose, 1024.63 mIU/ml and 3 463.21 mIU/ml respectively. But during the time from top GMT to 24th month, the GMT of Group B and C decreased rapidly to about 59.4% and 83% respectively, and it continually declined slowly at 36^th month to 459.68 mIU/ml and 506.23 mIU/ml, which were 6% and 15% lower than that at 24^th month. It showed that the antibody level in Group B and C after 2 doses were significantly higher than that in Group A from beginning to end, at 36th month the GMT of Group B and C were 4.6 times and 5.1 times to that of Group A, and the antibody positive rate (97%) was higher than that of Group A (80%) at the same time.

CONCLUSION

A single dose of live attenuated hepatitis A vaccine can come into being high and persistent protection against hepatitis A. Booster dose induces an immune response which persists for at least three years in 97% of the subjects. The high GMT still present at month 36 predicts a long-term persistence of antibody.

Hepatitis C virus infection in the general population: a community-based study in West Bengal, India

Limited information is available about the prevalence and genotype distribution of hepatitis C virus (HCV) in the general population of India. A community-based epidemiologic study was carried out in a district in West Bengal, India. By a 1:3 sampling method, 3,579 individuals were preselected from 10,737 inhabitants of 9 villages of the district, of whom 2,973 (83.1%) agreed to participate. Twenty-six subjects (0.87%) were HCV antibody positive. The prevalence increased from 0.31% in subjects <10 years of age to 1.85% in those >or=60 years. No difference in prevalence between men and women was observed. Serum alanine aminotransferase (ALT) levels were elevated in 30.8% (8 of 26) of anti-HCV-positive subjects compared with 3.2% (94 of 2,947) anti-HCV-negative subjects (P <.001). HCV RNA was detectable in 80.8% (95% CI, 65.6%-95.91%) of the anti-HCV-positive subjects by reverse transcription-primed polymerase chain reaction (RT-PCR). The participants were HCV types 1b in 2 (9.5%), 3a in 8 (38.1%), 3b in 6 (28.6%), and unclassified in 5 (23.8%). Nucleotide sequencing and phylogenetic analysis assigned the unclassified type to genotype 3e. In conclusion, this study provides general population-based estimates of HCV prevalence, including genotypes, from a South Asian country. Although the prevalence of HCV infection in this population was lower than that reported from industrialized countries of the west, the total reservoir of infection is significant and calls for public health measures, including health education to limit the magnitude of the problem.