Safety and immunogenicity of inactivated hepatitis A vaccine in patients with chronic liver disease

Prevention of Hepatitis A Virus Infection in the United States: Recommendations of the Advisory Committee on Immunization Practices, 2020

HEPATITIS A IS A VACCINE-PREVENTABLE, COMMUNICABLE DISEASE OF THE LIVER CAUSED BY THE HEPATITIS A VIRUS (HAV). THE INFECTION IS TRANSMITTED VIA THE FECAL-ORAL ROUTE, USUALLY FROM DIRECT PERSON-TO-PERSON CONTACT OR CONSUMPTION OF CONTAMINATED FOOD OR WATER. HEPATITIS A IS AN ACUTE, SELF-LIMITED DISEASE THAT DOES NOT RESULT IN CHRONIC INFECTION. HAV ANTIBODIES (IMMUNOGLOBULIN G [IGG] ANTI-HAV) PRODUCED IN RESPONSE TO HAV INFECTION PERSIST FOR LIFE AND PROTECT AGAINST REINFECTION; IGG ANTI-HAV PRODUCED AFTER VACCINATION CONFER LONG-TERM IMMUNITY. THIS REPORT SUPPLANTS AND SUMMARIZES PREVIOUSLY PUBLISHED RECOMMENDATIONS FROM THE ADVISORY COMMITTEE ON IMMUNIZATION PRACTICES (ACIP) REGARDING THE PREVENTION OF HAV INFECTION IN THE UNITED STATES. ACIP RECOMMENDS ROUTINE VACCINATION OF CHILDREN AGED 12-23 MONTHS AND CATCH-UP VACCINATION FOR CHILDREN AND ADOLESCENTS AGED 2-18 YEARS WHO HAVE NOT PREVIOUSLY RECEIVED HEPATITIS A (HEPA) VACCINE AT ANY AGE. ACIP RECOMMENDS HEPA VACCINATION FOR ADULTS AT RISK FOR HAV INFECTION OR SEVERE DISEASE FROM HAV INFECTION AND FOR ADULTS REQUESTING PROTECTION AGAINST HAV WITHOUT ACKNOWLEDGMENT OF A RISK FACTOR. THESE RECOMMENDATIONS ALSO PROVIDE GUIDANCE FOR VACCINATION BEFORE TRAVEL, FOR POSTEXPOSURE PROPHYLAXIS, IN SETTINGS PROVIDING SERVICES TO ADULTS, AND DURING OUTBREAKS.

Alginate-coated chitosan nanoparticles act as effective adjuvant for hepatitis A vaccine in mice

The numerous recent hepatitis A outbreaks emphasize the need for vaccination; despite the effectiveness of the current ones, developments are needed to overcome its high cost plus some immune response limitations. Our study aims to evaluate the use of chitosan and alginate-coated chitosan nanoparticles as an adjuvant/carrier for the hepatitis A vaccine (HAV) against the traditional adjuvant alum. Immune responses towards (HAV-Al) with alum, (HAV-Ch) with chitosan, and (HAV-aCNP) with alginate-coated chitosan nanoparticles, were assessed in mice. HAV-aCNP significantly improved the immunogenicity by increasing the seroconversion rate (100%), the hepatitis A antibodies level, and the splenocytes proliferation. Thus, the HAV-aCNP adjuvant was superior to other classes in IFN-γ and IL-10 development. Meanwhile, the solution formula of HAV with chitosan showed comparable humoral and cellular immune responses to alum-adjuvanted suspension with a balanced Th1/Th2 immune pathway. The current study showed the potential of alginate-coated chitosan nanoparticles as an effective carrier for HAV. Consequently, this would impact the cost of HAV production positively.

Factors That Influence the Immune Response to Vaccination

There is substantial variation between individuals in the immune response to vaccination. In this review, we provide an overview of the plethora of studies that have investigated factors that influence humoral and cellular vaccine responses in humans. These include intrinsic host factors (such as age, sex, genetics, and comorbidities), perinatal factors (such as gestational age, birth weight, feeding method, and maternal factors), and extrinsic factors (such as preexisting immunity, microbiota, infections, and antibiotics). Further, environmental factors (such as geographic location, season, family size, and toxins), behavioral factors (such as smoking, alcohol consumption, exercise, and sleep), and nutritional factors (such as body mass index, micronutrients, and enteropathy) also influence how individuals respond to vaccines. Moreover, vaccine factors (such as vaccine type, product, adjuvant, and dose) and administration factors (schedule, site, route, time of vaccination, and coadministered vaccines and other drugs) are also important. An understanding of all these factors and their impacts in the design of vaccine studies and decisions on vaccination schedules offers ways to improve vaccine immunogenicity and efficacy.

Update: Recommendations of the Advisory Committee on Immunization Practices for Use of Hepatitis A Vaccine for Postexposure Prophylaxis and for Preexposure Prophylaxis for International Travel

Postexposure prophylaxis (PEP) with hepatitis A (HepA) vaccine or immune globulin (IG) effectively prevents infection with hepatitis A virus (HAV) when administered within 2 weeks of exposure. Preexposure prophylaxis against HAV infection through the administration of HepA vaccine or IG provides protection for unvaccinated persons traveling to or working in countries that have high or intermediate HAV endemicity. The Advisory Committee on Immunization Practices (ACIP) Hepatitis Vaccines Work Group conducted a systematic review of the evidence for administering vaccine for PEP to persons aged >40 years and reviewed the HepA vaccine efficacy and safety in infants and the benefits of protection against HAV before international travel. The February 21, 2018, ACIP recommendations update and supersede previous ACIP recommendations for HepA vaccine for PEP and for international travel. Current recommendations include that HepA vaccine should be administered to all persons aged ≥12 months for PEP. In addition to HepA vaccine, IG may be administered to persons aged >40 years depending on the provider's risk assessment. ACIP also recommended that HepA vaccine be administered to infants aged 6-11 months traveling outside the United States when protection against HAV is recommended. The travel-related dose for infants aged 6-11 months should not be counted toward the routine 2-dose series. The dosage of IG has been updated where applicable (0.1 mL/kg). HepA vaccine for PEP provides advantages over IG, including induction of active immunity, longer duration of protection, ease of administration, and greater acceptability and availability.

Association of CMV, HBV, or HCV co-infection with vaccine response in adults with well-controlled HIV infection

Even after CD4 count recovery on antiretroviral therapy, HIV infection is associated with decreased response to most vaccines compared to the general population. Chronic infections with viruses such as cytomegalovirus (CMV), hepatitis B virus (HBV), and hepatitis C virus (HCV), which are more prevalent in HIV-infected populations, have been linked to immune dysfunction and decreased vaccine response in the general population. However, whether co-infection with these other viruses contributes to the decreased vaccine response seen in adults with well-controlled HIV infection is unknown. We conducted a secondary analysis of data and serum from adults with well-controlled HIV infection from an inactivated polio vaccine trial (224 subjects) and a pneumococcal conjugate vaccine study (128 subjects). We evaluated the association of CMV, HBV, or HCV co-infection with post-vaccination antibody levels using both univariate and multivariate analyses, controlling for factors such as age, race, CD4 count, comorbidities, smoking status, and baseline antibody levels. Ninety-three percent, 7%, and 14% of subjects were co-infected with CMV, HBV, and HCV respectively. On both univariate and multivariate analysis, neither CMV nor HCV co-infection were significantly associated with post-vaccination antibody levels to either vaccine. HBV co-infection was significantly associated with post-vaccination antibody concentrations for pneumococcal serotype 7F on univariate analysis and 6A on multivariate analysis, but the association was with higher antibody concentrations. In conclusion, co-infection with CMV, HBV, or HCV does not appear to contribute to the decreased vaccine response seen in adults with well-controlled HIV infection.

Development, production, and postmarketing surveillance of hepatitis A vaccines in China

China has long experience using live attenuated and inactivated vaccines against hepatitis A virus (HAV) infection. We summarize this experience and provide recent data on adverse events after immunization (AEFIs) with hepatitis A vaccines in China. We reviewed the published literature (in Chinese and English) and the published Chinese regulatory documents on hepatitis A vaccine development, production, and postmarketing surveillance of AEFI. We described the safety, immunogenicity, and efficacy of hepatitis A vaccines and horizontal transmission of live HAV vaccine in China. In clinical trials, live HAV vaccine was associated with fever (0.4%–5% of vaccinees), rash (0%–1.1%), and elevated alanine aminotransferase (0.015%). Inactivated HAV vaccine was associated with fever (1%–8%), but no serious AEFIs were reported. Live HAV vaccine had seroconversion rates of 83% to 91%, while inactivated HAV vaccine had seroconversion rates of 95% to 100%. Community trials showed efficacy rates of 90% to 95% for live HAV and 95% to 100% for inactivated HAV vaccine. Postmarketing surveillance showed that HAV vaccination resulted in an AEFI incidence rate of 34 per million vaccinees, which accounted for 0.7% of adverse events reported to the China AEFI monitoring system. There was no difference in AEFI rates between live and inactivated HAV vaccines. Live and inactivated HAV vaccines manufactured in China were immunogenic, effective, and safe. Live HAV vaccine had substantial horizontal transmission due to vaccine virus shedding; thus, further monitoring of the safety of virus shedding is warranted.

Management of infections in cirrhotic patients: report of a consensus conference

The statements produced by the consensus conference on infection in end-stage liver disease promoted by the Italian Association for the Study of the Liver, are here reported. The topics of epidemiology, risk factors, diagnosis, prophylaxis, and treatment of infections in patient with compensated and decompensated liver cirrhosis were reviewed by a scientific board of experts who proposed 26 statements that were graded according to level of evidence and strength of recommendation, and approved by an independent jury. Each topic was explored focusing on the more relevant clinical questions. By systematic literature search of available evidence, comparison and discussion of expert opinions, pertinent statements answering specific questions were presented and approved. Short comments were added to explain the basis for grading evidence particularly on case of controversial areas.

Changes in hepatitis A and B vaccination rates in adult patients with chronic liver diseases and diabetes in the U.S. population

Professional societies recommend hepatitis A and hepatitis B immunization for individuals with chronic liver disease (CLD), but the degree of implementation is unknown. Data were obtained from the National Health and Nutrition Examination Surveys (NHANES) conducted in 1999-2008. For the entire study population and for those with CLD and diabetes, we determined the rates and independent predictors of history of hepatitis A and hepatitis B (HepA and HepB) vaccinations, of their effectiveness, and of seroprevalence of hepatitis A antibody and anti-HB surface antibody. In total, 24,871 participants from NHANES were included: 14,886 (1999-2004) and 9,985 (2005-2008). Of these individuals, 14.0% had CLD and 8.6% had diabetes. During the study period, HepA vaccination in CLD increased from 13.3% ± 1.0% to 20.0% ± 1.5%, HepB vaccination increased from 23.4% ± 1.2% to 32.1% ± 1.5%. Of subtypes of CLD, HepA vaccination rates increased only in nonalcoholic fatty liver disease (NAFLD), whereas HepB vaccination increased for patients with hepatitis C and nonalcoholic fatty liver disease. In the diabetic cohort, HepA vaccination rates increased from 9.3% ± 1.1% to 15.4% ± 1.7% and HepB rates increased from 15.2% ± 1.5% to 22.4% ± 1.7%. All changes were similar to those observed in the general population. The quality measure (QM) for HepA in the general population decreased from 44.4% ± 1.2% in 1999-2004 to 41.7% ± 1.9% in 2005-2008, and similar changes were noted for all subcohorts. On the other hand, QM for HepB increased from 31.7% ± 0.9% to 40.7% ± 1.0% in the population, whereas no changes in QM were noted in any diagnostic cohort except for NAFLD.

CONCLUSIONS

Although vaccination rates in CLD and diabetic cohorts are increasing, they remain low. Given the public health implications of acute hepatitis A and hepatitis B in patients with CLD, better implementation of the vaccination recommendations for these populations is warranted.

Hepatitis A and hepatitis B vaccination responses in persons with chronic hepatitis C infections: A review of the evidence and current recommendations

In persons with chronic hepatitis C virus (HCV) infections, superinfection by hepatitis A virus (HAV) or hepatitis B virus (HBV) can cause serious complications, including fulminating hepatitis or increased severity of hepatitis. Therefore, it is important to adequately protect persons with chronic HCV infections by immunization. Suboptimal response to vaccines has been reported in patients with chronic liver disease. The present article reviews HAV and HBV vaccine responses reported in the literature when administered to individuals with chronic HCV infection, and reviews current national and international recommendations.

RESULTS

Persons with chronic HCV respond well to HAV vaccine, but studies exploring HBV vaccine efficacy in this population have equivocal results. Vaccine schedules and participant characteristics differ among studies, and most do not adjust for confounders. Some studies found no difference in HBV vaccine response between patients with chronic HCV and controls. However, HBV vaccine response was generally reduced in those with cirrhosis and HCV genotype 1. Organizations recommend HAV and HBV vaccines for persons with chronic HCV, but do not suggest alterations in schedule or dose.

RECOMMENDATIONS

Because HAV vaccine response is good and routine laboratory testing may not detect lower levels of vaccine-induced anti-HAV, the standard HAV vaccine schedule is recommended without postimmunization testing. HBV vaccine should be administered early in the course of chronic HCV infection because response may be lower in patients with cirrhosis. Reflex testing of anti-HCV reactive sera for anti-HAV and hepatitis B surface antibody can facilitate appropriate follow-up and timely immunization. Determination of postimmunization hepatitis B surface antibody, especially in patients with cirrhosis or genotype 1, will allow HBV vaccine boosters to be offered.

The Seroconversion Rate of Hepatitis A Virus Vaccination among Patients with Hepatitis B Virus-Related Chronic Liver Disease in Korea

BACKGROUND/AIMS

The aim of this study was to evaluate the seroconversion rate of a hepatitis A virus (HAV) vaccination in patients with hepatitis B virus (HBV)-related chronic liver disease (CLD).

METHODS

Analyses were conducted using clinical records from 94 patients with chronic HBV infection who were seronegative for IgG anti-HAV antibodies between September 2008 and June 2009. Two doses of an HAV vaccine were administered 24 weeks apart. A third vaccine dose was administered only for patients seronegative for anti-HAV antibodies at week 48.

RESULTS

The seroconversion rate of anti-HAV following the two-dose vaccination was 86.17%. The seroconversion rate of anti-HAV was not significantly different according to age or status of liver disease. The rate was higher in female than in male patients. A third HAV vaccine dose was administered to 13 patients seronegative for anti-HAV after the two-dose regimen, and 84.62% of these patients showed seroconversion at week 72.

CONCLUSIONS

HAV vaccination is effective in most Korean patients with HBV-related CLD, and it might be necessary to evaluate three-dose vaccination approach for non-responders to the conventional regimen to maximize the success of an HAV vaccination program.

Preserved MHC-II antigen processing and presentation function in chronic HCV infection

Individuals with chronic HCV infection have impaired response to vaccine, though the etiology remains to be elucidated. Dendritic cells (DC) and monocytes (MN) provide antigen uptake, processing, presentation, and costimulatory functions necessary to achieve optimal immune responses. The integrity of antigen processing and presentation function within these antigen presenting cells (APC) in the setting of HCV infection has been unclear. We used a novel T cell hybridoma system that specifically measures MHC-II antigen processing and presentation function of human APC. Results demonstrate MHC-II antigen processing and presentation function is preserved in both myeloid DC (mDC) and MN in the peripheral blood of chronically HCV-infected individuals, and indicates that an alteration in this function does not likely underlie the defective HCV-infected host response to vaccination.

Response to hepatitis A and B vaccine alone or in combination in patients with chronic hepatitis C virus and advanced fibrosis

Patients with advanced fibrosis are at increased risk of severe outcomes if they develop acute infection with hepatitis A (HAV) or hepatitis B (HBV) viruses. There are no data on the efficacy of combined HAV/HBV vaccination in patients with advanced fibrosis. Our aim was to evaluate the response to the HAV and HBV vaccine alone or in combination for patients with chronic hepatitis C (HCV) and advanced fibrosis and to evaluate the impact of administering the vaccine while patients were receiving peginterferon for treatment of chronic HCV. In this prospective study of patients with advanced fibrosis (Ishak 3-6), those without serologic evidence of prior exposure were vaccinated with either Havrix HAV, Engerix( HBV, or the TWINRIX HAV/HBV combination vaccine as appropriate, and response was defined as the development of anti-HAV or anti-HBV surface antibodies. Of the 162 eligible patients, the prevalence of prior exposure to HAV and HBV was 30 and 18%, respectively. Of the 84 patients vaccinated, 38% received Havrix, 14% Engerix, and 48% TWINRIX. The response to the HAV vaccine was 75% in those receiving Havrix compared to 78% receiving TWINRIX. In contrast, the response to HBV vaccination was 42% in patients receiving Engerix compared to 60% in those vaccinated with TWINRIX (difference 18.3%; OR 0.29; 95% CI: 0.57-7.79). The presence of diabetes was the only risk factor identified for reduced HBV response (P = 0.01). Responses to both HAV and HBV vaccines when administered alone or in combination were lower than expected in patients with HCV and advanced fibrosis, especially in those with diabetes. The observation that the decline in HBV vaccine response was somewhat lower when this was administered alone as opposed to the combination A/B vaccine suggests that the administration of a combination vaccine may enhance the vaccination response to HBV.

[Efficacy and safety of vaccination against hepatitis A and B in patients with chronic liver disease]

Vaccination to protect against hepatitis A and B should be part of the routine management of patients with chronic liver disease (CLD).

OBJECTIVES

To evaluate the efficacy and safety of hepatitis A virus (HAV) and hepatitis B virus (HBV) vaccination in a group of patients with CLD and to assess the presence of factors predictive of response.

PATIENTS AND METHODS

We performed a prospective, single-center study in 194 patients (123 men, 71 women; mean age, 48.9+/-10.7 years) with CLD: 107 with chronic hepatitis (CH) and 87 with hepatic cirrhosis (HC), all Child-Pugh class A. The most frequent causes of CLD were HCV infection and alcohol. Patients negative for anti-HAV IgG received the HAV vaccination (1440 ELISA units in two doses) and those with negative HBV serology received the HBV vaccination ( three 20 microg doses). Patients with inadequate response to the latter vaccine received an additional double dose. Thirty patients received a combination vaccine (three doses).

RESULTS

Sixty patients (31%) received the HAV vaccine and 150 (77%) patients received the HBV vaccine. Seroconversion was achieved by 91.6% of patients for HAV and by 57% of the patients for HBV. After the additional dose, the response increased to 74%. Efficacy was similar between CH and HC. HBV vaccination was less effective in HC than in CH and the seroconversion rate was significantly lower in patients with HC and previous decompensation. The combination vaccine (30 patients) was highly immunogenic. No adverse effects were registered.

CONCLUSIONS

HAV vaccination has high efficacy in patients with CLD. Patients with HC respond weakly to HBV vaccination compared with those with CH and especially if there is prior decompensation. The combination vaccine seems particularly effective in patients with CLD. The three vaccines are safe.

Health maintenance issues in cirrhosis

Caring for patients with cirrhosis requires special consideration. The role of the hepatologist is to assist the primary care physician in caring for such patients. This involves an active role in immunizations, lifestyle modifications, and providing instructions on when to go to the emergency room (ER). There are also specific recommendations geared toward the patient with cirrhosis relating to slowing down the disease process, maintaining quality of life, and improving survival.

Functionality of the immune system in patients with chronic hepatitis C: trial by superinfections and vaccinations

Viral infections, specifically chronic, markedly influence the host response to subsequent infections and vaccinations. Does this apply to chronic hepatitis C (CHC)? The review considers this question with implications for the immune status and functionality of the immune system of a chronically HCV-infected host. The data collected here indicate that CHC may increase the risk of viral superinfections and modify their course by immunocompromising the host. Patients with CHC do not lose the 'memory' of previous infections and vaccinations but, apparently, have problems with building such immunity anew, as illustrated by their impaired response to hepatitis A and B vaccinations. This underlines the necessity of extra protection of CHC patients against blood-borne diseases, hepatitis A, possibly also varicella, influenza, tetanus, and diphtheria - immunity to which, in the Western population, appears to falter. Such immune protection has to be adapted to selective impairments of immune response characteristic to CHC. Some approaches to this are reviewed here and more need to be elaborated. Special attention has to be given to CHC patients who do not respond to common vaccines; further studies in this field are of great interest.

Acute hepatitis A and B in patients with chronic liver disease: prevention through vaccination

Retrospective and prospective studies have demonstrated that the occurrence of acute hepatitis A in patients with chronic liver disease is associated with higher rates of morbidity and mortality than in previously healthy individuals with acute hepatitis A. The mortality associated with acute hepatitis A may be particularly high in patients with preexisting chronic hepatitis C. Although acute hepatitis B in patients with preexisting chronic liver disease is less well studied, worse outcomes than in previously healthy individuals are apparent. However, numerous studies convincingly demonstrate that chronic hepatitis B virus coinfection with hepatitis C virus (or hepatitis D virus) is associated with an accelerated natural history of liver disease and worse outcomes. These observations led to studies that demonstrated the safety and efficacy of hepatitis A and hepatitis B vaccination in patients with mild-to-moderate chronic liver disease. Hepatitis A and B vaccination is less effective in patients with advanced liver disease, especially after decompensation, such as in patients awaiting liver transplantation, and in liver transplant recipients. The emerging lower rates of inherent immunity in younger individuals, higher morbidity and mortality of acute hepatitis A or B superimposed on chronic liver disease, and greater vaccine efficacy in milder forms of chronic liver disease suggest that it is a reasonable policy to recommend hepatitis A and B vaccination in patients early in the natural history of chronic liver disease.

Immunization of pediatric solid-organ transplantation candidates: immunizations in transplant candidates

Many children who receive solid-organ transplants have not completed their primary immunizations prior to transplantation. This leaves pediatric transplant recipients susceptible to the vaccine preventable illness of childhood, which if acquired post-transplantation are associated with increased rates of complications, hospitalization, graft rejection and mortality. The administration of vaccines to transplant candidates earlier and more rapidly than in the healthy child will improve vaccination rates among transplant recipients while not compromising immunogenicity. The recommended vaccines and vaccine schedule are discussed in detail.

Susceptibility to hepatitis A in patients with chronic liver disease due to hepatitis C virus infection: missed opportunities for vaccination

Hepatitis A virus (HAV) superinfection is associated with a high risk of liver failure and death in patients with underlying chronic liver disease. Although HAV vaccination is recommended for all patients with chronic hepatitis C virus (HCV) infection, little is known about adherence to these recommendations in clinical practice. The aims of this study were to determine the frequency of HAV testing and vaccination among patients with chronic HCV infection. We conducted a retrospective cohort study of 1,193 patients diagnosed with chronic HCV infection over a 1-year period. During 1,646 person-years of follow-up, patients were seen by their primary care provider a median of 10.0 times (interquartile range, 4.0-20.0). HAV antibody testing was performed in 640 subjects (53.6%), and 317 (49.5%) of those tested were susceptible (HAV antibody negative). Only 94 of the 1,193 patients (7.9%) received the HAV vaccine, including 26.8% of the 317 susceptible patients, 0.9% of the 323 patients who were already immune to HAV, and 1.1% of the 553 subjects who were never tested. Among the 94 vaccinated patients, 45 received only one dose of the vaccine. Three of the unvaccinated patients developed acute HAV infection during follow-up, and 1 of them died of acute liver failure. In conclusion, despite published recommendations to vaccinate against HAV in patients with chronic HCV infection, we found that HAV testing and vaccination rates were low in clinical practice. Public health programs to increase awareness about HAV vaccination in patients with chronic liver disease are needed.

Immunisation in the current management of cystic fibrosis patients

Although no special recommendations exist, clearly patients with cystic fibrosis (CF) can benefit from immunisation. We reviewed the literature regarding vaccination in CF and other chronic diseases. CF subjects should follow national immunisation programmes without delay to obtain optimal vaccination coverage. Indeed they may escape normal programmes due to frequent hospital admissions and school absenteeism and may be more at risk to get "vaccine-controlled" diseases at any age. There is no uniform European immunisation schedule for basic infant and childhood vaccines or for vaccines against hepatitis A (HAV) and B (HBV), varicella (VZ) and booster vaccinations. HAV and HBV vaccination is appropriate in CF as recommended in general for patients with chronic liver disease (CLD). Varicella (VZ) vaccination is not recommended in all European countries. There are no recent data about possible worsening of pulmonary status following VZ in CF, but it is known to cause pulmonary damage in non-CF adults and to be potentially fatal post transplantation and during steroid treatment. Therefore it is recommended at least for seronegative adolescents and transplant candidates. Influenza vaccine is recommended annually for CF patients aged > or =6 months. Pneumococcal vaccine is generally indicated for CF patients. RSV infection might play a role in the initial Pseudomonas colonization and the decline in pulmonary function. However no RSV vaccine is available at present. There are no recommendations for palivizumab in CF as an alternative but expensive prophylaxis. Anti-bacterial vaccinations protecting directly against Pseudomonas aeruginosa colonisation are promising for the future, potential candidates are currently being assessed in phase III clinical trials. More studies are needed to complete recommendations especially for CF adults and transplant candidates.

Hepatitis B vaccine efficacy in patients with chronic liver disease by hepatitis C virus

BACKGROUND

Considering the immunosuppression of patients with chronic liver disease, their response to vaccination is discussed in literature.

AIMS

To evaluate the response of hepatitis B vaccine in patients with chronic hepatitis C virus infection.

METHODS

This is a prospective study in which 85 patients with chronic hepatitis C virus infection (46.8 +/- 9.4 years, 44.7% males) and 46 healthy adults (36.7 +/- 11.1 years; 39.1% males) were evaluated. Confirmation of hepatitis C virus was obtained by the technique of polymerase chain reaction. Viral load was determined by the branched DNA method in 74 patients, and genotype was determined by sequencing in 73 patients. All patients and healthy adults received three doses of Engerix B vaccine IM (at 0, 30 and 180 days). Serological responses to the vaccine were divided into three categories: seroprotection, when anti-HBs was > or =100 mUI/mL; seroconversion, when anti-HBs was 10-99 mUI/mL, and non-reagent, when anti-HBs was <10 mUI/mL.

RESULTS

The response of hepatitis B vaccine as determined 1 month following dose 3 was seroprotection in 37.7%, seroconversion in 17.6% and non-reagent in 44.7% among patients and 84.8%, 13.0%, 2.2%, respectively in healthy adults. The number of non-reagent responses was significantly higher among those patients with chronic liver disease. Sixty-five patients with chronic hepatitis were compared to 20 compensated cirrhotic patients in concern to the response to vaccine, but no difference was found. The response to vaccine in patients with genotypes 2 or 3 (n = 40) was better than in those with genotype 1 (n = 33). Response was not related to serum HCV-RNA concentration.

CONCLUSION

The number of non-responders was higher in patients with chronic hepatitis C virus infection, irrespective of histological status and viral load. It is suggested that such patients should receive a double dose of vaccine, particularly the ones with genotype 1.

Immunogenicity of inactivated hepatitis A vaccine in children with chronic liver disease

One and 6 months after vaccination with hepatitis A virus vaccine (HAVRIX 720 Junior), immunologic responses (anti-hepatitis A virus >/=20 mIU/ml) in children with chronic hepatitis C infection seroprotection were 92% (23/25) and 75% (9/12) in children with chronic hepatitis B infection 87% (21/24) and 88% (15/17) and in healthy children 91% (20/22) at both times. A booster dose induced seroprotection in all children.

Hepatitis A booster vaccination: is there a need?

Hepatitis A is one of the most common vaccine-preventable infectious diseases in the world. Effective vaccines against hepatitis A have been available since 1992, and they provide long-term immunity against the infection. However, there is no worldwide consensus on how long protection will last or whether there will be a need for hepatitis A virus (HAV) booster vaccinations in the future. In most countries, booster-vaccination policy is guided by manufacturers' recommendations, national authorities, or both. In June, 2002, a panel of international experts met to review the long-term immunogenicity and protection conferred by HAV vaccine in different population groups. Data have shown that after a full primary vaccination course, protective antibody amounts persist beyond 10 years in healthy individuals, and underlying immune memory provides protection far beyond the duration of anti-HAV antibodies. The group concluded that there is no evidence to lend support to HAV booster vaccination after a full primary vaccination course in a healthy individual. However, further investigations are needed before deciding if boosters can be omitted in special patient-groups.

Hepatitis A virus infection in hepatitis C Brazilian patients

OBJECTIVE

HAV infection in patients with pre-existing chronic liver disease has been associated with increased rate of fulminant hepatitis and mortality. The aim of this study was to investigate the presence of serological and molecular HAV markers in a population of HCV infected patients.

PATIENTS AND METHODS

The presence of total and IgM anti-HAV antibodies was investigated in 197 patients (mean age 44.8+/-12.5 years) referred to the Brazilian Reference Center for Viral Hepatitis and who tested positive for anti-HCV antibodies and HCV RNA. HAV RNA was investigated by reverse transcription-nested PCR in these patients.Results. One hundred seventy patients (86%) had total, but not IgM anti-HAV antibodies, being therefore, immune to hepatitis A, while 27 (14%) were not. A high proportion (6/27, 22%) of the susceptible patients presented markers of recent HAV infection: One patient was IgM anti-HAV positive, three were HAV RNA positive, and two presented both markers. By nucleotide sequencing, it was demonstrated that the HAV isolates infecting these patients belonged to subgenotypes 1A and 1B.

CONCLUSIONS

Superinfection with HAV was a common event in the group of HCV infected patients under study. Implementation of hepatitis A vaccination should be considered for this population.

Vaccinations for adult solid-organ transplant recipients: current recommendations and protocols

Recipients of solid-organ transplantation are at risk of severe infections due to their life-long immunosuppression. Despite emerging evidence that vaccinations are safe and effective among immunosuppressed patients, most vaccines are still underutilized in these patients. The efficacy, safety, and protocols of several vaccines in this patient population are poorly understood. Timing of vaccination appears to be critical because response to vaccinations is decreased in patients with end-stage organ disease and in the first 6 months after transplantation. For these reasons, the primary immunizations should be given before transplantation, as early as possible during the course of disease. Vaccination strategy should include vaccination of household contacts and health care workers at transplant centers unless contraindicated. No conclusive data are available on the use of immunoadjuvants and screening for protective titers. Most vaccines appear to be safe in solid-organ transplantation recipients, but live vaccines should be avoided until further studies are available. The risk of rejection appears minimal. Recommended vaccines include pneumovax, hepatitis A and B, influenza, and tetanus-diphtheria. We outline specific protocols and recommendations in this particular patient population. Specific contraindications exist for other vaccines, such as yellow fever, oral polio vaccine, bacillus Calmette-Guerin, and vaccinia. We conclude that solid-organ recipients will benefit from consistent immunization practices. Further studies are recommended to improve established protocols in this patient population.

HAV infection in chronic liver disease: a rationale for vaccination

We report the conduct and results of a systematic search of the literature to assess whether exposure to HAV could induce a fatal deterioration of liver diseases. We assessed 30 studies and found evidence of progressive decrease of natural immunity against HAV in Italy. HAV vaccine seems as safe in chronic liver diseases than in general population. On the basis of the evidence we recommend that subjects with chronic liver disease should be vaccinated against HAV, especially if younger than 40 years.

Hepatitis A vaccine in pediatric patients affected by metabolic liver diseases

Twenty children with a variety of metabolic liver diseases were given two doses of hepatitis A vaccine. Adverse reactions were mild. All subjects responded to vaccine with seroconversion to hepatitis A virus antibodies after the first dose, regardless of transaminase values, and had a booster effect from the second doses.

Risks associated with hepatitis A and hepatitis B in patients with hepatitis C

Individuals with hepatitis C virus (HCV) are at risk for acquiring hepatitis A virus (HAV) or hepatitis B virus (HBV) because of shared risk factors. A number of organizations recommend vaccination against HAV and HBV for patients with HCV. The rationale for vaccinating these patients is to prevent hepatic superinfections. Acute HAV superinfection causes more severe disease, acute hepatic failure, and higher fatality rates in patients with underlying chronic liver disease, specifically chronic HBV infection and chronic HCV infection. Available data, although limited, suggest that HBV coinfection with HAV and HCV causes more severe hepatic injury than infection with HAV or HCV alone. At standard doses, hepatitis A and hepatitis B vaccines are safe and immunogenic in patients with mild-to-moderate hepatitis C or chronic liver disease. Regardless of disease severity, vaccination should be routinely administered to patients upon diagnosis of HCV infection. Early vaccination is important because response to vaccination is reduced as liver disease progresses. Prevaccination and postvaccination serology testing is recommended in specific populations. A new combination hepatitis A and hepatitis B vaccine has been shown to be as safe and effective as monovalent hepatitis A and B vaccines and is currently under review by the United States Food and Drug Administration. A combination vaccine would offer ease of administration and convenience and could increase compliance in patients with hepatitis C or other chronic liver disease: two groups that should be more aggressively targeted by healthcare professionals.

Hepatitis A: old and new

The hepatitis A virus (HAV), a picornavirus, is a common cause of hepatitis worldwide. Spread of infection is generally person to person or by oral intake after fecal contamination of skin or mucous membranes; less commonly, there is fecal contamination of food or water. Hepatitis A is endemic in developing countries, and most residents are exposed in childhood. In contrast, the adult population in developed countries demonstrates falling rates of exposure with improvements in hygiene and sanitation. The export of food that cannot be sterilized, from countries of high endemicity to areas with low rates of infection, is a potentially important source of infection. After ingestion and uptake from the gastrointestinal tract, the virus replicates in the liver and is excreted into the bile. Cellular immune responses to the virus lead to destruction of infected hepatocytes with consequent development of symptoms and signs of disease. Humoral immune responses are the basis for diagnostic serologic assays. Acute HAV infection is clinically indistinguishable from other causes of acute viral hepatitis. In young children the disease is often asymptomatic, whereas in older children and adults there may be a range of clinical manifestations from mild, anicteric infection to fulminant hepatic failure. Clinical variants include prolonged, relapsing, and cholestatic forms. Management of the acute illness is supportive, and complete recovery without sequelae is the usual outcome. Research efforts during World War II led to the development of passive immunoprophylaxis. Pooled immune serum globulin is efficacious in the prevention and attenuation of disease in exposed individuals. More recently, active immunoprophylaxis by vaccination has been accomplished. Future eradication of this disease can now be contemplated.

Viral hepatitis. From prevention to antivirals

The challenge of viral hepatitis has been acknowledged and confronted in the last decade. Significant progress in prevention of infection with HAV and HBV may eradicate these serious infections from the United States and other parts of the world in the coming decades. Application of prophylactic strategies to children will be a major mechanism in accomplishing this task. The quest for potent antiviral medications continues. The next critically important development will be ways to prevent new HCV infections and to treat the millions of already infected individuals at risk for the serious consequences of this disease. For pediatricians, realizing these goals requires a greater understanding of perinatal HCV transmission, use of vaccines for prevention of viral hepatitis, and identification of HCV-infected children who are likely to benefit from new therapeutic strategies as they become available.

Asian perspectives on viral hepatitis A

Recent decades have witnessed a marked decline in the prevalence of hepatitis A virus (HAV) infection in Asian populations, especially in children. This is attributable to general improvements in socio-economic status and hygiene, which have, in turn, made a large population of young adults susceptible to the disease. The HAV infection rarely results in death and mortality is age-dependent. According to previous reports, it may be more severe in persons with underlying chronic liver disease (CLD). Because most parts of Asia are areas of endemic hepatitis B and C virus infection, where chronic hepatitis B and C are the most important causes of CLD, it is therefore imperative for patients with CLD to be protected against HAV infection. Several studies have been conducted into the success of immunization against HAV in different risk groups. Given the increasing potential for HAV epidemics and the success and safety of the HAV vaccines, mass immunization against the infection seems possible and rational in Asia.

Hepatitis A vaccination in patients with chronic liver disease in Taiwan

While hepatitis A infection is rarely fatal, mortality is age-dependent, suggesting that cofactors may play a role in disease expression. The safety and immunogenicity of an inactivated hepatitis A vaccine was evaluated in a study involving 60 patients with chronic liver disease (CLD) (56 patients with chronic hepatitis B, and four patients with chronic hepatitis C). A two-dose schedule, at 0 and 6 months, produced 100% seroconversion. All individuals remained seropositive for 12 months, the majority maintaining high levels of antibody during a 5-year follow-up period. The inactivated hepatitis A vaccine was found to be well tolerated and immunogenic in patients with CLD. However, the immune response generated was inferior to that observed in healthy individuals, indicating the need for a higher dose, and the two-dose schedule to ensure adequate protection.

The cost-effectiveness of hepatitis A vaccination in patients with chronic hepatitis C

Infection with hepatitis A virus (HAV) occasionally leads to acute liver failure and has a higher fatality rate in patients with chronic hepatitis C virus (HCV). Vaccination of patients with HCV against HAV is effective and well tolerated. This study examines the cost-effectiveness of HAV vaccination in North American patients with chronic HCV. A decision analysis model was constructed to compare 3 HAV vaccination strategies in adult patients with chronic HCV over a period of 5 years: (1) vaccinate no patients (treat none); (2) vaccinate only susceptible (anti-HAV negative) patients (selective); or (3) vaccinate all patients without prior testing of immune status (universal). Probabilities and direct costs were estimated from hospital data and the literature. The cost per patient for the 3 vaccination strategies were: treat none, $2.00; selective, $56.00; and universal, $82.00. For every 1,000,000 patients with HCV vaccinated over a 5-year period, the selective strategy prevented 128 symptomatic cases of HAV, 3 liver transplantations, and 3 deaths owing directly to HAV compared with the treat none strategy. In addition, the selective strategy costs an additional $427,000 per patient with HAV prevented, and $23 million per HAV-related death averted, compared with the treat none strategy. The results were most sensitive to the incidence of HAV infection; vaccination increased costs if the annual rate of infection was less than 0.56% (baseline, 0.01%). Vaccination of North American patients with chronic HCV against HAV infection is not a cost-effective therapy.

Viral hepatitis A, B, and C

Mankind probably has known viral hepatitis for many centuries; however, the major and most dramatic developments in our knowledge of these diseases have taken place during the second half of the 20th century. During this relatively short period of time, the infectious nature of hepatitis A, B, and C has been proven, leading to their identification and description. The advent of serologic markers has provided the means for establishing the diagnosis. Epidemiologic studies have provided important information that led to exciting achievements in detection and prevention of transmission. Molecular biology studies and cell culture techniques have established our knowledge of the viral genomes, and led to the development of specific vaccines for hepatitis A and B. Anti-viral therapy has been developed and aggressive combination therapy has emerged as a promising strategy for chronic hepatitis B and C. This article reviews some of the main fields of progress and achievement related to viral hepatitis A, B, and C in the 20th century.

Inactivated hepatitis A vaccine in Chinese patients with chronic hepatitis B infection

BACKGROUND

Hepatitis B (HBV)-infected patients have a higher morbidity and mortality when super-infected by hepatitis A (HAV).

AIM

To evaluate the immunogenicity and safety of a commercial inactivated HAV vaccine in Chinese patients with chronic HBV infection.

METHODS

Sixty-five HBV-infected patients (30 carriers, 22 chronic hepatitis, 13 cirrhosis), who were seronegative for HAV, received a dose of 1440 ELISA units of HAV vaccine at weeks 0 and 24. Twenty-eight healthy individuals aged 18-57 years, who were seronegative for both HBV and HAV infection, also received the same vaccination regimen. Seroconversion was defined as an anti-HAV titre >/= 33 mIU/mL.

RESULTS

The seroconversion rates for the HBV-infected patients at weeks 2, 4 and 24 were 72, 91 and 80%, respectively. The corresponding geometric mean titres (GMTs) were 103, 311 and 123 mIU/mL. In the healthy control group the seroconversion rates were 86, 93 and 89% at weeks 2, 4 and 24. The corresponding GMTs were 112, 158 and 250 mIU/mL. There was no difference in the seroconversion rates between the two groups, but healthy controls had a significantly higher GMT at week 24 (P=0.04). Side-effects were more common in HBV patients.

CONCLUSION

The HAV vaccine is equally efficacious in patients with chronic HBV infection.

Long-term follow-up of hepatitis A vaccination in children

We conducted this follow-up study to evaluate the long-term immunogenicity of an inactivated hepatitis A vaccine in children. Ninety-six children who had seroconversion to antibody to HAV (anti-HAV) after receiving a three-dose schedule of inactivated hepatitis A vaccine were enrolled into this study. Sixty months after the initial vaccination, all vaccinees who received annual follow-up still had protective levels of anti-HAV. The geometric mean titer (GMT) of anti-HAV, peaking at month 7 (4133 mIU/mL), kept declining throughout the follow-up period. The GMTs in months 12, 24, 36, 48 and 60 were 1722, 896, 896, 645 and 403 mIU/mL, respectively. Nine of the vaccinees were hepatitis B virus carriers. Their anti-HAV titers tended to be lower than those of the remaining vaccinees at all time-points, but the difference was not significant (p > 0.05). Natural booster was noted in one vaccinee during the follow-up period. In conclusion, inactivated hepatitis A vaccine is safe and immunogenic in children, the duration of protection against HAV infection is longer than five years.