Epidemiology of hepatitis A before and after the introduction of a universal vaccination programme in Catalonia, Spain

Hepatitis a Vaccine as Opportunity of Primary Prevention for Food Handlers: A Narrative Review

The hepatitis A virus (HAV) is still a leading cause of viral hepatitis worldwide. After a long incubation period, the clinical manifestations range from asymptomatic infection to acute liver failure. The severity of the disease increases with age and pre-existing liver disease. The transmission is mainly via person-to-person contact or ingestion of contaminated food or water. Food contamination can occur at any step of the food chain, especially when infected people handle not-heated or otherwise-treated food. HAV is endemic in low-income countries because of poor sanitary and sociodemographic conditions. The populations of developed countries are highly susceptible, and large outbreaks occur when HAV is introduced from endemic countries due to globalization, travel, and movement of foodstuffs. HAV prevention includes hygiene practices, immunoglobulins, and vaccination. Safe and effective inactivated and live attenuated vaccines are available and provide long-term protection. The vaccine targets are children and subjects at increased risk of HAV exposure or serious clinical outcomes. This review discusses the critical role of food handlers in the spread of HAV and the opportunity for food industry employers to consider food handler immunization a tool to manage both food safety in compliance with HACCP principles and food operators' biologic risk.

Changes in the epidemiology of hepatitis A: Clinical and preventive implications

INTRODUCTION AND OBJECTIVES

Hepatitis A Virus Infection (HAI) has been related to the hygienic-sanitary situation of an area, the changes in the epidemiology of HAI in the province of Guadalajara between 1991 and 2017 are analyzed.

MATERIALS AND METHODS

Cases of HAI declared between 1991 and 2017 in Guadalajara were included. The variables analyzed were age, sex, environment, risk factors for HAI and need for hospitalization. The incidence was compared in three periods: 1991-1999, 2000-2008 and 2009-2017.

RESULTS

Two hundred and thirty-three cases of HAI were declared, the average incidence rate was 4.27 cases/100,000 inhabitants, highest between 1991 and 1999 (6.93) and lowest between 2009 and 2017 (1.92), with an increment in 2017 (5.5). The median age was 16 years (IR: 8.5-28.5 years), 58.4% were male, and the highest incidence occurred between 5 and 14 years in both sexes. The most frequent risk factors were family and non-family contact and trips to endemic areas (18.6%, 17.3% and 18.2%, respectively). The last risk factor increased after 2000 (P=.001), as did the incidence in urban areas. The MSM group showed an increase in the last period (P<.001). Hospital admissions increased progressively from the first to the third period studied (P=.001).

CONCLUSIONS

HAI has a low incidence in our area. More cases related to travel or sexual practices are observed. This should be considered when establishing prevention policies, including vaccination of the most exposed people.

Sexual behaviour and poor hygiene are related to recent hepatitis a virus community outbreaks

OBJECTIVES

there has been a global increase in the incidence of hepatitis A infection. The aim of this study was to examine the characteristics of the increase in our region and the degree of adherence to the recommended hygienic measures after discharge from hospital.

METHODS

demographic, clinical and biochemical variables were collected from patients with acute hepatitis A in our health area. The patients were grouped as follows: January 2010 to December 2016 (historical cohort) and January 2017 to October 2017 (recent cohort). A phylogenetic analysis was also performed in the recent cohort. One month after discharge, bacterial growth was evaluated by a culture of the dominant hand imprint and were compared with a control group.

RESULTS

a total of 110 cases were registered with a median age of 36.3 years (range 3-89) and 77.3 % were male. The incidence was 0.82/100,000 inhabitants/year and 22.75/100,000 inhabitants/year in the historical and recent cohorts, respectively. Patients in the recent cohort were more frequently male (52.6 % vs. 82.4 %, p = 0.008) and younger (51.7 [3-89] vs. 33.4 [4-74] years, p < 0.001). In addition, 63.8 % of the recent cohort were men who had sex with other men and had unsafe sexual practices (37.5 %). Phylogenetic analysis showed a predominance of genotype A and a high frequency of the VRD 521-2016 sequence. A higher growth of enterobacteria was observed in patients with hepatitis A compared to the control group (7.3 % vs. 1.2 %, p = 0.005), despite specific hygienic measures given at discharge.

CONCLUSIONS

a recent outbreak of hepatitis A in our area was related with gender, younger age and sexual practices. Hepatitis A infected subjects showed a poor adherence to hygienic measures. Our data suggests the need for policies that encourage preventive actions, particularly vaccination in this high-risk group.

Seroprevalence and susceptibility to hepatitis A in the European Union and European Economic Area: a systematic review

Most of the European Union (EU) and European Economic Area (EEA) is considered a region of very low hepatitis A virus (HAV) endemicity; however, geographical differences exist. We did a systematic review with the aim of describing seroprevalence and susceptibility in the general population or special groups in the EU and EEA. We searched databases and public health national institutes websites for HAV seroprevalence records published between Jan 1, 1975, and June 30, 2014, with no language restrictions. An updated search was done on Aug 10, 2016. We defined seroprevalence profiles (very low, low, and intermediate) as the proportion of the population with age-specific anti-HAV antibodies at age 15 and 30 years, and susceptibility profiles (low, moderate, high, and very high) as the proportion of susceptible individuals at age 30 and 50 years. We included 228 studies from 28 of 31 EU and EEA countries. For the period 2000-14, 24 countries had a very low seroprevalence profile, compared with five in 1975-89. The susceptibility among adults ranged between low and very high and had a geographical gradient, with three countries in the low susceptibility category. Since 1975, EU and EEA countries have shown decreasing seropositivity; however, considerable regional variability exists. The main limitations of this study are that the studies retrieved for analysis might not be representative of all EU and EEA publications about HAV and might have poor national representativeness. A large proportion of EU and EEA residents are now susceptible to HAV infection. Our Review supports the need to reconsider specific prevention and control measures, to further decrease HAV circulation while providing protection against the infection in the EU and EEA, and could be used to inform susceptible travellers visiting EU and EEA countries with different HAV endemicity levels.

Impact of universal mass vaccination with monovalent inactivated hepatitis A vaccines - A systematic review

The WHO recommends integration of universal mass vaccination (UMV) against hepatitis A virus (HAV) in national immunization schedules for children aged ≥1 year, if justified on the basis of acute HAV incidence, declining endemicity from high to intermediate and cost-effectiveness. This recommendation has been implemented in several countries. Our aim was to assess the impact of UMV using monovalent inactivated hepatitis A vaccines on incidence and persistence of anti-HAV (IgG) antibodies in pediatric populations. We conducted a systematic review of literature published between 2000 and 2015 in PubMed, Cochrane Library, LILACS, IBECS identifying a total of 27 studies (Argentina, Belgium, China, Greece, Israel, Panama, the United States and Uruguay). All except one study showed a marked decline in the incidence of hepatitis A post introduction of UMV. The incidence in non-vaccinated age groups decreased as well, suggesting herd immunity but also rising susceptibility. Long-term anti-HAV antibody persistence was documented up to 17 y after a 2-dose primary vaccination. In conclusion, introduction of UMV in countries with intermediate endemicity for HAV infection led to a considerable decrease in the incidence of hepatitis A in vaccinated and in non-vaccinated age groups alike.

Immunogenicity, effectiveness and safety of combined hepatitis A and B vaccine: a systematic literature review

BACKGROUND

Hepatitis A and B are two of the most common vaccine-preventable diseases and vaccination for Hepatitis A virus (HAV) and hepatitis B virus (HBV) is recommended for those at risk of contracting HAV and/or HBV through their occupation, travel or lifestyle.

OBJECTIVE

To describe the vaccine efficacy, immunogenicity, effectiveness and safety of the combined vaccine against hepatitis A and hepatitis B.

METHODS

A systematic review of the literature published between 1990 and 2015.

RESULTS

Anti-HAV seropositivity rates ranged from 96.2% to 100% and anti-HBs seroprotection rates from 82% to 100%. Antibodies persisted up to 15 years and geometric mean concentration (GMC) remained above the seropositivity cut-off value for both. Anti-HAV and anti-HBs immune responses were lower in less immunocompetent individuals one month after completion of the immunization schedule. The safety profiles of Twinrix(TM) and monovalent hepatitis A and B vaccines were similar.

CONCLUSION

The vaccine offers satisfactory long-term immunogenicity rates, expected duration of protection and safety profile similar to the monovalent hepatitis A or B vaccines.

The costs of hepatitis A infections in South Korea

OBJECTIVES:

The incidence of hepatitis A infections among young adults has recently increased in South Korea. Although universal vaccination has often been suggested to mitigate the problem, its rationale has not been well-understood. Estimating the societal costs of hepatitis A infections might support the development of intervention strategies.

METHODS:

We classified hepatitis A infections into eight clinical pathways and estimated the number of occurrences and cost per case for each clinical pathway using claim data from National Health Insurance and several national surveys as well as assumptions based on previous studies. To determine the total costs of a hepatitis A infection, both direct and indirect costs were estimated. Indirect costs were estimated using the human-capital approach. All costs are adjusted to the year 2008.

RESULTS:

There were 30,240 identified cases of hepatitis A infections in 2008 for a total cost of 80,873 million won (2.7 million won per case). Direct and indirect costs constituted 56.2% and 43.8% of the total costs, respectively. People aged 20-39 accounted for 71.3% of total cases and 74.6% of total costs. Medical costs per capita were the lowest in the 0-4 age group and highest in the 20-29 age group.

CONCLUSIONS:

This study could provide evidence for development of cost-effective interventions to control hepatitis A infections. But the true costs including uncaptured and intangible costs of hepatitis A infections might be higher than our results indicate.

Immunogenicity and safety of an inactivated hepatitis A vaccine when coadministered with measles-mumps-rubella and varicella vaccines in children less than 2 years of age

BACKGROUND

Hepatitis A vaccination in early childhood has reduced hepatitis A transmission. Coadministration of hepatitis A vaccine with other childhood vaccines may assist completion of the age-appropriate immunization schedule. We assessed the immunogenicity and safety of an inactivated hepatitis A virus vaccine when coadministered with measles-mumps-rubella (MMR) and varicella vaccines in children less than 2 years of age.

METHODS

In this open-label, randomized, multicenter study, 3 groups of healthy children 15 months of age received either 2 doses of hepatitis A vaccine 6 to 9 months apart (n = 324), hepatitis A vaccine coadministered with MMR and varicella vaccines and a second dose of hepatitis A vaccine 6 to 9 months later (n = 462), or MMR and varicella vaccines followed 6 weeks later by 2 doses of hepatitis A vaccine 6 to 9 months apart (n = 455). Immune responses were evaluated at baseline, 31 days after the second dose of hepatitis A vaccine, and 42 days after MMR and varicella vaccine administration. Solicited, unsolicited, and serious adverse events were collected.

RESULTS

After 2 doses of hepatitis A vaccine, nearly all subjects in all groups were seropositive (≥99%). Coadministration of hepatitis A vaccine with MMR and varicella vaccines did not impact the immunogenicity of any of the vaccines and was well tolerated.

CONCLUSIONS

The immune response to hepatitis A vaccine and US-licensed MMR and varicella vaccines is not adversely affected when coadministered in children 15 months of age.

Decline in HAV-associated fulminant hepatic failure and liver transplant in children in Argentina after the introduction of a universal hepatitis A vaccination program

INTRODUCTION

Hepatitis A virus (HAV) infection is a vaccine-preventable disease. The most severe complication in children is fulminant hepatic failure (FHF), estimated to occur in 0.4% of cases; patients with FHF often require a liver transplant (LT). Following another outbreak of HAV infection in Argentina during 2003-2004, a one-dose HAV universal immunization (UI) program was started in 2005, resulting in a reduction in the incidence of HAV infection. We have investigated the impact of HAV UI on the trends in the occurrence of FHF and LT in children.

METHODS

All pediatric cases of FHF admitted to four pediatric centers in Buenos Aires during March 1993-July 2005 were retrospectively reviewed, and data of cases during August 2005-December 2008 were collected. Information about demography, HAV infections and vaccination status, diagnostic data for FHF using the Pediatric Acute Liver Failure criteria, clinical laboratory results, encephalopathy, the severity of liver disease using the Pediatric End Stage Liver Disease score, assessment of patients on the LT waiting list using King's College Criteria for LT, treatment given for FHF (pre- and post-transplant), and clinical outcome were collected using a case report form. The frequency and outcomes of HAV-associated FHF and LT cases before and after UI were analyzed.

RESULTS

During the pre-immunization period, March 1993-July 2005, 54.6% (N = 165) of FHF cases were caused by HAV; HAV-associated FHF cases peaked during 2003-2004. During the post-immunization period, August 2005-December 2008, only 27.7% (N = 18) of FHF cases were caused by HAV infection; only one of these patients had received the HAV vaccine (one dose only). The number of HAV-associated FHF cases decreased from 2005, and no cases were reported from November 2006-December 2008. Multivariate analyses showed that the association of FHF with HAV infection rather than other etiologies decreased with increasing age (P = 0.03), UI against HAV (P = 0.002), and anti-actin antibodies (P = 0.002), and increased with increasing weight (P = 0.0004).

CONCLUSIONS

The number of children with HAV-associated FHF in Argentina has strongly decreased since the initiation of the UI program. Further monitoring is required to confirm the long-term health and economic benefits of UI against HAV infection.

Immunogenicity and safety of an inactivated hepatitis A vaccine when coadministered with Diphtheria-tetanus-acellular pertussis and haemophilus influenzae type B vaccines in children 15 months of age

BACKGROUND

This study (NCT00197236) evaluated the safety and immunogenicity of a hepatitis A virus (HAV) vaccine when coadministered with diphtheria-tetanus-acellular pertussis (DTaP) and Haemophilus influenzae type b (Hib) vaccines in children 15 months of age.

METHODS

This was an open-labeled, multicenter study with healthy subjects enrolled and randomized (1:1:1) into 3 treatment groups. A total of 394 subjects received the first study vaccinations at 15 months of age. Group HAV (N = 135) received 2 doses of HAV vaccine 6 to 9 months apart. Group HAV+DTaP+Hib (N = 127) received HAV vaccine coadministered with DTaP and Hib vaccines and the second dose of HAV vaccine, 6 to 9 months later. Group DTaP+Hib→HAV (N = 132) received the DTaP and Hib vaccines at 15 months of age, followed by HAV vaccine 30 days later and the second dose of HAV vaccine 7 to 10 months after the DTaP+Hib vaccines. Immune responses were evaluated before the first study vaccination and 30 days after each vaccine dose. Solicited, unsolicited, and serious adverse events were collected.

RESULTS

After 2 doses of the HAV vaccine, all subjects in the 3 groups were seropositive. The geometric mean concentration of anti-HAV antibodies ranged between 1625.1 and 1904.4 mIU/mL. Coadministration of the 3 vaccines did not impact immunogenicity of the HAV, DTaP, or Hib vaccines. Vaccines were well tolerated in all groups.

CONCLUSIONS

A 2-dose schedule of HAV vaccine was well tolerated and immunogenic when administered to children starting at 15 months of age. Immune responses to the DTaP or Hib vaccines were similar whether they were administered alone or were coadministered with the HAV vaccine.

Antibody persistence and immune memory in healthy adults following vaccination with a two-dose inactivated hepatitis A vaccine: long-term follow-up at 15 years

Long-term persistence of vaccine-induced immune response in adults was assessed annually for 15 years following primary immunization with a two-dose inactivated hepatitis A vaccine. In 1992, 119 and 194 subjects aged 17-40 years and naïve for hepatitis A virus (HAV) were enrolled in two studies to receive 1,440 ELISA units (El.U) of inactivated hepatitis A vaccine (Havrix™, GlaxoSmithKline Biologicals, Belgium) according to a standard 0, 6 or an extended 0, 12 months schedule, respectively. Serum samples were taken 1 month after the second vaccine dose and every consecutive year up to 15 years after primary vaccination for measurement of anti-HAV antibody concentrations (NCT00291876 and NCT00289757). At year 15, 100% (48/48) and 97.3% (108/111) of subjects vaccinated at 0, 6 or 0, 12 months remained seropositive for anti-HAV antibodies, with geometric mean concentrations (GMCs) of 289.2 and 367.4 mIU/ml, respectively. An additional dose of HAV vaccine (1,440 El.U) was administered to the six subjects who had become seronegative for anti-HAV antibodies since year 11. All subjects mounted a humoral immune response to the additional HAV challenge dose, although post-challenge anti-HAV antibody levels remained low in one subject. These studies represent the longest annual follow-up of hepatitis A vaccine in healthy adults. The immune response induced by two doses of this inactivated HAV vaccine was shown to persist for at least 15 years. No difference in long-term antibody persistence was observed between the two primary vaccination schedules, reinforcing the potential for flexibility in the timing of the second primary vaccine dose.