Hepatitis A vaccine

Recent advances in hepatitis A virus research and clinical practice guidelines for hepatitis A virus infection in Japan

In 2018, there was a hepatitis A outbreak in Japan, and hepatitis A virus (HAV) infection is considered a sexually transmitted disease. In general, patients with hepatitis A should be given attention, and this disease should be prevented more than ever. The Japan Agency for Medical Research and Development (AMED) Hepatitis A and E viruses (HAV and HEV) Study Group has worked on the project to create "Recent Advances in Hepatitis A Virus (HAV) Research and Clinical Practice Guidelines for HAV Infection in Japan". The group consists of expert hepatologists and virologists who gathered at virtual meeting on August 5, 2023. Data about the pathogenesis, infection routes, diagnosis, complications, several factors for the severities, vaccination, and current and future treatments for hepatitis A were discussed and debated for a draft version. The participants assessed the quality of cited studies. The finalized recommendations are presented in this review. The recent advances in HAV research and clinical practice for HAV infection in Japan, have been reviewed by the AMED HAV and HEV Study Group.

Interferon Inhibition Enhances the Pilot-Scale Production of Rabies Virus in Human Diploid MRC-5 Cells

Inactivated vaccines based on cell culture are very useful in the prevention and control of many diseases. The most popular strategy for the production of inactivated vaccines is based on monkey-derived Vero cells, which results in high productivity of the virus but has a certain carcinogenic risk due to non-human DNA contamination. Since human diploid cells, such as MRC-5 cells, can produce a safer vaccine, efforts to develop a strategy for inactivated vaccine production using these cells have been investigated using MRC-5 cells. However, most viruses do not replicate efficiently in MRC-5 cells. In this study, we found that rabies virus (RABV) infection activated a robust interferon (IFN)-β response in MRC-5 cells but almost none in Vero cells, suggesting that the IFN response could be a key limiting factor for virus production. Treatment of the MRC-5 cells with IFN inhibitors increased RABV titers by 10-fold. Additionally, the RABV titer yield was improved five-fold when using IFN receptor 1 (IFNAR1) antibodies. As such, we established a stable IFNAR1-deficient MRC-5 cell line (MRC-5^IFNAR1−), which increased RABV production by 6.5-fold compared to normal MRC-5 cells. Furthermore, in a pilot-scale production in 1500 square centimeter spinner flasks, utilization of the MRC-5^IFNAR1− cell line or the addition of IFN inhibitors to MRC cells increased RABV production by 10-fold or four-fold, respectively. Thus, we successfully established a human diploid cell-based pilot scale virus production platform via inhibition of IFN response for rabies vaccines, which could also be used for other inactivated virus vaccine production.

Viral hepatitis: Milestones, unresolved issues, and future goals

In this review the current overall knowledge on hepatitis A, B, C, D, and E will be discussed. These diseases are all characterized by liver inflammation but have significant differences in distribution, transmission routes, and outcomes. Hepatitis B virus and hepatitis C virus are transmitted by exposure to infected blood, and in addition to acute infection, they can cause chronic hepatitis, which in turn can evolve into cirrhosis. It is estimated that more than 300 million people suffer from chronic hepatitis B or C worldwide. Hepatitis D virus, which is also transmitted by blood, only affects hepatitis B virus infected people, and this dual infection results in worse liver-related outcomes. Hepatitis A and E spread via the fecal-oral route, which corresponds mainly to the ingestion of food or water contaminated with infected stools. However, in developed countries hepatitis E is predominantly a zoonosis. Although hepatitis A virus and hepatitis E virus are usually responsible for a self-limiting hepatitis, a serious, rarely fatal illness is also possible, and in immunosuppressed patients, such as organ transplant recipients, hepatitis E virus infection can become chronic. The description of goals achieved, unresolved issues, and the latest research on this topic may make it possible to speculate on future scenarios in the world of viral hepatitis.

Hepatitis A vaccine for immunosuppressed patients with rheumatoid arthritis: a prospective, open-label, multi-centre study

BACKGROUND

Hepatitis A vaccine is the most frequently used travel vaccine, yet data are scarce about its ability to induce protection in patients with concurrent immunosuppressive treatment. We assessed the immunogenicity of this vaccine in rheumatoid arthritis (RA) patients treated with tumour necrosis factor-inhibitors (TNFi) and/or methotrexate (MTX).

METHODS

Hepatitis A vaccine was administered to non-immune RA patients at 0 and 6 months. Hepatitis A virus (HAV) antibodies were assessed at 0, 1, 6, 7, 12, and 24 months with a quantitative Chemiluminescent Microparticle Immuno Assay (CMIA) for HAV-IgG. Samples from month 1, 6, and 7 were, in addition, analysed with a microparticle EIA (MEIA) for anti-HAV IgM + IgG.

RESULTS

The final study population consisted of 53 patients treated with TNFi (n = 15), TNFi + MTX (n = 21) or MTX (n = 17). One and six months after the first dose, 10% and 33% of the patients had attained seroprotection. One and six months after the second dose 83% and 72% were seroprotected. At month 24, 86% of the vaccinees showed protective levels.

CONCLUSIONS

Two doses of hepatitis A vaccine at a 6-month interval provided protection for most immunosuppressed RA patients. A single dose does not seem to afford sufficient protection to this group of patients.

Low level of immunity against hepatitis A among Korean adolescents: vaccination rate and related factors

BACKGROUND

We evaluated the current vaccination rate and immunity in the Korean adolescent population and analyzed their parents' attitudes toward hepatitis A virus (HAV) vaccination.

METHODS

Between March and April 2011, sera were collected for immunoglobulin (Ig) G anti-HAV testing from students in their first year of high school from 12 different high schools located in southwestern Seoul. Simultaneously, questionnaires were given to the parents of the students to evaluate factors related to HAV vaccination, including demographics, HAV vaccination status, reason for getting the vaccination, and awareness regarding HAV.

RESULTS

Sera from 2,879 subjects and questionnaires from their parents were collected. The HAV vaccination rate among adolescents aged between 14 and 17 years was 18.9%, and the seroprevalence was 15.4%. Among subjects who reported receiving the HAV vaccination, the IgG anti-HAV seropositivity rate was only 42.2%. For subjects who were not vaccinated, the IgG anti-HAV seropositivity rate was 9.1%. The most significant reason for receiving the vaccination was recommendation from health care providers; the most important source of information regarding the vaccination was public health organizations.

CONCLUSION

HAV vaccination rate and anti-HAV seroprevalence in Korean adolescents was low; the seropositivity rate in the vaccinated group was lower than expected. Actively recommending HAV vaccination in this group is required, and routine, nationwide, government-sponsored vaccination of adolescents against HAV should be considered.

Immunogenecity of hepatitis A and B vaccination in pediatric patients with inflammatory bowel disease

OBJECTIVES

Aim of the study was to evaluate the response to hepatitis A and B vaccination in pediatric patients with inflammatory bowel disease (IBD).

METHODS

A total of 47 patients with IBD (25 ulcerative colitis, 14 Crohn's disease, and 8 indeterminate colitis) ages 3 to 17 years were compared with 50 healthy age- and sex-matched controls. Screening for hepatitis A and B serology was carried out before vaccination. Susceptible cases received 20 mg of recombinant DNA vaccine for hepatitis B (0, 1, and 6 months)and 720 milliELISA units of inactivated hepatitis A virus vaccine (HAV) (0 and 6 months). Postvaccination serologic evaluation was performed 1 month after the last dose of primary vaccination, 1 month after the booster dose, and once every year during follow-up.

RESULTS

A total of 23 patients and 35 controls received HAV and protective anti-HAV antibodies were developed in all of the patients and controls (P =1.00). Forty-seven patients and 50 controls received hepatitis B vaccine and 70.2% of the patients versus 90% of the controls achieved seroprotection(anti-HBs titers 10 mIU/mL) 1 month after primary vaccination (95% confidence interval 0.71–0.87, P = 0.02). The overall seroprotection rates were 96% in controls and 85.1% in patients after the whole hepatitis B vaccination series (95% confidence interval 0.83–0.95, P = 0.08). No significant reduction was observed in antibody response among patients and controls during the follow-up period.

CONCLUSIONS

The rate of seroconversion to the hepatitis B vaccine was lower in pediatric patients with IBD than in healthy controls and hepatitis A vaccine was highly immunogenic among patients with IBD.

Response to hepatitis A and B vaccination in pediatric patients with celiac disease

OBJECTIVES

The aim of the study was to evaluate the response to hepatitis A and B vaccinations in pediatric patients with celiac disease (CD).

METHODS

Thirty patients with CD ages 1 to 15 years were compared with 50 healthy age-, sex-, and body mass index-matched controls. Screening for hepatitis A and B serology was carried out before vaccination. Susceptible cases received 20 μg of recombinant DNA vaccine for hepatitis B (0,1, and 6 months) and 720 milliELISA units of inactivated hepatitis A virus (HAV) vaccine (0 and 6 months). Postvaccination serologic evaluation was performed 1 month after the last dose of primary vaccination, 1 month after the booster dose, and once every year during follow-up.

RESULTS

Sixteen patients and 35 controls received hepatitis A vaccine; protective anti-HAV antibodies were developed in 12 (75%) of the patients and all of the controls (75% vs 100%, respectively; 95% confidence interval [CI] 0.47-0.92, P=0.007). Thirty patients and 50 controls received hepatitis B vaccine, and 70% of the patients vs 90% of the controls achieved seroprotection (anti-HBs titers ≥10 mIU/mL) 1 month after primary vaccination (95% CI 0.74-0.90, P=0.03). Four patients were unresponsive to both of the vaccines. The overall seroprotection rates were 96% in controls and 80% in patients after the whole hepatitis B vaccination series (95% CI 0.04-0.18, P=0.04). No significant reduction was observed in antibody response among patients and controls during follow-up period.

CONCLUSIONS

The rate of seroconversion to the hepatitis B virus- and HAV vaccine is lower in patients with CD than in healthy controls.

Influenza A (H1N1) 2009 pandemic calm down the prevalence of acute hepatitis A in the latter half of 2009: Korean population study

BACKGROUND/AIMS

There was a spiking incidence of acute hepatitis A (AHA) in 2009 summer, but it went down drastically after an outbreak of influenza A (H1N1). We assessed the relationship between 2009 H1N1 pandemic and AHA prevalence from August to December 2009.

METHODS

We compared AHA cases nationwide and in our hospital for the period from the latter half of 2008 to the end of 2010. H1N1 cases in our hospital from August 2009 to December 2009 were included in the study and the correlation between 2009 H1N1 pandemic and AHA prevalence was assessed.

RESULTS

The national surveillance system reported 2,233, 7,895, 15,231 and 7,660 AHA cases from 2007 to 2010, respectively. A similar trend was noted in our hospital in the same periods. Although the national total incidence was increased in 2009, it showed steep decreasing trend line in the final 21 weeks of 2009 (weeks 32-52), as compared with 2008 and 2010. The mean weekly incidence percentage (AHA cases in a week/total in a year) in weeks 32-52 of 2009 was 1.17±0.55%, significantly lower than that in 2008 and 2010 (1.61±0.43% and 1.56±0.51%; p<0.001). Furthermore, we found a significant negative correlation between 2009 H1N1 pandemic and AHA in our hospital for weeks 32-52 of 2009 (r=-0.597; p<0.001).

CONCLUSIONS

The widespread occurrence of 2009 H1N1 pandemic highlighted the benefits of health care and good hygiene, such as effective hand washing and wearing of masks, which may have also interrupted hepatitis A virus transmission.

Interchangeability of a hepatitis A vaccine second dose: Avaxim 80 following a first dose of Vaqta 25 or Havrix 720 in children in Turkey

INTRODUCTION

This randomised, observer-blind clinical trial conducted in Turkey evaluated the immunogenicity, safety and interchangeability of three paediatric inactivated hepatitis A vaccines in 424 seronegative children between 1 and 15 years of age.

METHODS

Potential subjects were screened for anti-hepatitis A virus (HAV) antibodies prior to receiving a first dose of Avaxim 80, Havrix 720 or Vaqta 25, followed by a second dose of either the same vaccine or Avaxim 6 months later. Anti-HAV antibody concentrations were measured 2 weeks after the first injection, at 24 weeks (before the second dose) and at 28 weeks for the evaluation of the immune response.

RESULTS

Nearly 80% of the children between 1 and 5 years of age and half of those between the ages of 6 and 10 in the population from which the subjects were recruited were seronegative for HAV antibodies. Two weeks after the first dose, 98.2% of all subjects had anti-HAV antibody concentrations equal to or higher than 20 mIU/mL, believed to be seroprotective, and all subjects were seroprotected before and after the second dose. Anti-HAV geometric mean concentrations (GMCs) 2 weeks after the first dose and before the second were similar in children who received Avaxim and Vaqta (P = 0.2), but both were higher than Havrix (P < 0.01). There were no significant differences in the anti-HAV GMCs between the study groups that received two doses of the same vaccine compared with two doses of different vaccines. There were no significant differences in the frequency of any local or systemic adverse events among the study groups following either of the two doses.

CONCLUSION

All three vaccines are safe and highly immunogenic in healthy children aged 1 to 15 years. Avaxim 80 may also be given as the second dose when Havrix 720 or Vaqta 25 are given as the first dose. The pattern of seroprevalence seen here is similar to that reported in a number of recent evaluations in Turkey, and are supportive of the routine hepatitis A vaccination of young children.

A dynamic model for assessing universal Hepatitis A vaccination in Canada

Vaccination against Hepatitis A virus (HAV) in Canada is currently targeted toward high-risk groups. However, universal vaccination has been adopted in several other countries with a similar disease burden. Here we develop an age-structured compartmental model of HAV transmission and vaccination in Canada to assess potential universal vaccination strategies. The model predicts that universal vaccination at age 1 (respectively 4, 9, 15), with phasing out of targeted vaccination, would reduce reported incidence by 60% (respectively 52, 36, 31%) and mortality attributable to HAV by 56% (respectively 45, 26, 25%), relative to continued targeted vaccination, over 80 years.

Hepatitis A vaccines: the growing case for universal immunisation of children

Hepatitis A virus (HAV) infection results in a debilitating, multi-week illness in older children and adults that can be avoided with pre-exposure immunisation. Inactivated HAV vaccines are safe, highly effective and induce long-lasting protection. Immunisation has typically been recommended only for groups at highest risk of infection or complications, with variable success. This paper reviews the outcomes of several new programmes of universal HAV immunisation of children and/or adolescents. These programmes were associated with substantial disease rate reductions, extending beyond the immunised individuals and age groups (herd immunity), and promise additional benefits as immunised cohorts enter adulthood risk groups. Universal programmes are cost-effective, especially when a combined hepatitis A and B vaccine can be used to minimise incremental costs, and deserve wider consideration in developed countries.

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.

The cost effectiveness of hepatitis immunization for US college students

Hepatitis B immunization is recommended for all American children, and hepatitis A immunization is recommended for children who live in areas with elevated disease rates. Because hepatitis A and B occur most commonly in young adults, the authors examined the cost effectiveness of college-based vaccination. They developed epidemiologic models to consider infection risks and disease progression and then compared the cost of vaccination with economic, longevity, and quality of life benefits. Immunization of 100,000 students would prevent 1,403 acute cases of hepatitis A, 929 cases of hepatitis B, and 144 cases of chronic hepatitis B. Hepatitis B vaccination would cost the health system $7,600 per quality-adjusted life year (QALY) gained but would reduce societal costs by 6%. Hepatitis A/B vaccination would cost the health system dollar 8,500 per QALY but would reduce societal costs by 12%. Until childhood and adolescent vaccination can produce immune cohorts of young adults, college-based hepatitis immunization can reduce disease transmission in a cost-effective manner.