Decreasing immunity to hepatitis A virus infection among US adults: Findings from the National Health and Nutrition Examination Survey (NHANES), 1999-2012

Attenuation of hepatitis A antibody after immunization with hepatitis A vaccine (Aimmugen) in people living with HIV

AIM

Hepatitis A (HA) is a vaccine-preventable disease. In regions with good sanitation, men who have sex with men (MSM) are the key affected populations. During the 2018-2019 HA outbreak among MSM in Japan, we actively vaccinated MSM living with HIV (MSM-LWHIV) with Aimmugen. As previously reported, their antibody seroconversion rate due to vaccination was lower than that of healthy individuals. However, the durability of Aimmugen in people living with HIV has not yet been reported. We evaluated attenuation after the one-series vaccination (comprising three inoculations) and the factors associated with attenuation.

METHODS

We retrospectively examined anti-HA immunoglobulin G (anti-HA-IgG) titers and other clinical data from our hospital's medical records. Patients with no history of vaccination or HA infection (i.e., negative HA-IgG titers) who received one series of Aimmugen, achieved seropositivity, and anti-HA-IgG antibodies were tested ≥2 years after three doses were included. Fisher's exact test and the Mann-Whitney U-test were performed. p < 0.05 was considered statistically significant.

RESULTS

Fifty-one MSM-LWHIV were included. All were seropositive after the third dose with a median HA-IgG titer of 10.1 (interquartile range, 7.2-12.2) (sample/cut-off values [s/co]). In 45 (40-49) months, seropositivity decreased to 90% (46/51) and was attenuated to a median of 4.4 (2.3-6.5) s/co. Lower baseline B cell counts (p = 0.049), lower anti-HA-IgG levels after the second dose (p = 0.002), and lower anti-HA-IgG levels after the third dose (p = 0.003) were associated with seronegativity.

CONCLUSIONS

Anti-HA-IgG titers of vaccinated MSM-LWHIV may be attenuated; thus, additional immunizations should be considered.

High-performance enrichment-based genome sequencing to support the investigation of hepatitis A virus outbreaks

IMPORTANCE

This proof-of-concept study introduces a hybrid capture oligo panel for whole-genome sequencing of all six human pathogenic hepatitis A virus (HAV) subgenotypes, exhibiting a higher sensitivity than some conventional genotyping assays. The ability of hybrid capture to enrich multiple targets allows for a single, streamlined workflow, thus facilitating the potential harmonization of molecular surveillance of HAV with other enteric viruses. Even challenging sample matrices can be accommodated, making them suitable for broad implementation in clinical and public health laboratories. This innovative approach has significant implications for enhancing multijurisdictional outbreak investigations as well as our understanding of the global diversity and transmission dynamics of HAV.

Point-of-Care Testing for Hepatitis Viruses: A Growing Need

Viral hepatitis, caused by hepatitis A virus (HAV), hepatitis B virus (HBV), hepatitis C virus (HCV), hepatitis D virus (HDV), or hepatitis E virus (HEV), is a major global public health problem. These viruses cause millions of infections each year, and chronic infections with HBV, HCV, or HDV can lead to severe liver complications; however, they are underdiagnosed. Achieving the World Health Organization's viral hepatitis elimination goals by 2030 will require access to simpler, faster, and less expensive diagnostics. The development and implementation of point-of-care (POC) testing methods that can be performed outside of a laboratory for the diagnosis of viral hepatitis infections is a promising approach to facilitate and expedite WHO's elimination targets. While a few markers of viral hepatitis are already available in POC formats, tests for additional markers or using novel technologies need to be developed and validated for clinical use. Potential methods and uses for the POC testing of antibodies, antigens, and nucleic acids that relate to the diagnosis, monitoring, or surveillance of viral hepatitis infections are discussed here. Unmet needs and areas where additional research is needed are also described.

Predictors of hepatitis A immunity in adults in California in order to better utilize hepatitis A vaccine

BACKGROUND

Hepatitis A vaccine recommendations now include homelessness, illegal drug use, and HIV, as well as traditional risk factors and travel to areas endemic for hepatitis A. We examined a large diverse population for predictors of Hepatitis A immunity in order to better utilize Hepatitis A vaccine.

METHODS

We performed a cross-sectional descriptive study of members of a large integrated health plan with a test for Hepatitis A Immunoglobulin G (IgG) between January 1st, 2007, and December 31st, 2017. Exclusion criteria included age <18 years, <6 months of continuous enrollment, and Hepatitis A vaccine prior to Hepatitis A test. Variables of interest were age, gender, primary language spoken, ethnicity/race, neighborhood household income, and history of travel or history of jaundice. Multivariable logistic regression was performed to evaluate the association of risk factors on Hepatitis A immunity.

RESULTS

Of the 318,170 persons ≥ 18 years tested for Hepatitis A immunity, 155, 842 persons had a reactive Hepatitis A IgG test (49%). The lowest prevalence was for Whites at 28.1% followed by Blacks at 35.8%. Hispanics and Asian/Pacific Islanders had prevalence rates of 63% and 68.2% respectively. In adjusted analyses, Asian/Pacific Islanders, Hispanics and Blacks were 5.17, 3.44 and 1.42 times more likely to have Hepatitis A immunity than Whites. Those that spoke Spanish or language other than English or Spanish as their primary preferred language were 6.11 and 3.27 time more likely to have immunity than English speakers. Known travel history conferred a 2.16 likelihood of Hepatitis A immunity.

CONCLUSIONS

Persons of Hispanic and Asian/Pacific Islander background as well as persons with a preferred spoken language other than English have a high prevalence of Hepatitis A immunity. Testing for Hepatitis A immunity prior to vaccination should be considered for these groups.

Prevalence of Anti-Hav IgG Antibodies in the Population of the Łódź Macroregion by Age Group

Over the last several decades, a gradual decrease in the incidence of hepatitis A and an increase in the population of non-immune people, especially in the group of young people have been observed in Poland. The aim of this study was to assess of the presence of specific anti-hepatitis A virus IgG class antibodies (anti-HAV IgG) in relation to age among non-vaccinated hepatitis A patients. There were statistically significantly more patients up to 45 years of age with anti-HAV IgG negative results than those over 45 years of age, and the Fi-square correlation coefficient (Φ2) was 0.263 between the analyzed variables. The data analysis shows that the number of people with specific IgG antibodies against hepatitis A increases with age. The risk of hepatitis A infection in people under 45 is high due to widespread seronegativity in this age group.

Changing Molecular Epidemiology of Hepatitis A Virus Infection, United States, 1996-2019

Hepatitis A virus (HAV) genotype IA was most common among strains tested in US outbreak investigations and surveillance during 1996-2015. However, HAV genotype IB gained prominence during 2016-2019 person-to-person multistate outbreaks. Detection of previously uncommon strains highlights the changing molecular epidemiology of HAV infection in the United States.

Insight into an acute hepatitis A outbreak in Indiana

Hepatitis A virus (HAV) infection causes an acute enteric hepatitis associated with substantial morbidity and mortality, particularly in older individuals. Incidence of HAV infection is low in the United States, mostly related to consumption of contaminated food. Starting in 2017, Indiana reported a large HAV outbreak. We sought to characterize the risk-exposures, clinical features and outcomes of HAV and examine the differences based on underlying cirrhosis and age. Adults ≥18 years diagnosed with HAV between January 2017 and April 2019 at two large healthcare systems in Indiana were identified. Demographic data, risk-exposures, clinical features, laboratory data and clinical outcomes were collected for analysis. The HAV cohort constituted 264 individuals with mean age of 41-years, 62% male and 94% Caucasian. Risk-exposures identified were illicit drug use (74%), food-borne (15%), person-to-person (11%) and incarceration (11%). Mortality rate was 2%, acute liver failure (ALF) was seen in 4% and acute on chronic liver failure (ACLF) was seen in 30% (6 of 20 with underlying cirrhosis). Admission MELD score was the only factor associated with ALF [OR = 1.17 (1.08-1.2), p < 0.0001], on multivariable logistic regression analysis. Higher proportion of individuals with underlying cirrhosis developed acute kidney injury (AKI) (26% vs. 9%, p = 0.03), ascites (45% vs. 11%, p < 0.0001) and hepatic encephalopathy (35% vs. 4%, p < 0.0001). In conclusion, illicit drug use was the predominant risk-exposure in the current HAV outbreak, which was associated with 2% mortality rate, and those with cirrhosis had worse outcomes (AKI, ascites and HE), of whom 30% developed ACLF.

Hepatitis A vaccination and its immunological and epidemiological long-term effects - a review of the evidence

Hepatitis A virus (HAV) infections continue to represent a significant disease burden causing approximately 200 million infections, 30 million symptomatic illnesses and 30,000 deaths each year. Effective and safe hepatitis A vaccines have been available since the early 1990s. Initially developed for individual prophylaxis, HAV vaccines are now increasingly used to control hepatitis A in endemic areas. The human enteral HAV is eradicable in principle, however, HAV eradication is currently not being pursued. Inactivated HAV vaccines are safe and, after two doses, elicit seroprotection in healthy children, adolescents, and young adults for an estimated 30-40 years, if not lifelong, with no need for a later second booster. The long-term effects of the single-dose live-attenuated HAV vaccines are less well documented but available data suggest they are safe and provide long-lasting immunity and protection. A universal mass vaccination strategy (UMV) based on two doses of inactivated vaccine is commonly implemented in endemic countries and eliminates clinical hepatitis A disease in toddlers within a few years. Consequently, older age groups also benefit due to the herd protection effects. Single-dose UMV programs have shown promising outcomes but need to be monitored for many more years in order to document an effective immune memory persistence. In non-endemic countries, prevention efforts need to focus on 'new' risk groups, such as men having sex with men, prisoners, the homeless, and families visiting friends and relatives in endemic countries. This narrative review presents the current evidence regarding the immunological and epidemiological long-term effects of the hepatitis A vaccination and finally discusses emerging issues and areas for research.

Hepatitis A Person-to-Person Outbreaks: Epidemiology, Morbidity Burden, and Factors Associated With Hospitalization-Multiple States, 2016-2019

BACKGROUND

Since 2016, the United States has experienced person-to-person hepatitis A outbreaks unprecedented in the vaccine era. The proportion of cases hospitalized in these outbreaks exceeds historical national surveillance data.

METHODS

We described the epidemiology, characterized the reported increased morbidity, and identified factors associated with hospitalization during the outbreaks by reviewing a 10% random sample of outbreak-associated hepatitis A cases in Kentucky, Michigan, and West Virginia-3 heavily affected states. We calculated descriptive statistics and conducted age-adjusted log-binomial regression analyses to identify factors associated with hospitalization.

RESULTS

Participants in the random sample (n = 817) were primarily male (62.5%) with mean age of 39.0 years; 51.8% were hospitalized. Among those with available information, 73.2% reported drug use, 14.0% were experiencing homelessness, 29.7% were currently or recently incarcerated, and 61.6% were epidemiologically linked to a known outbreak-associated case. Residence in Michigan (adjusted risk ratio [aRR] = 1.8), being a man who has sex with men (aRR = 1.5), noninjection drug use (aRR = 1.3), and homelessness (aRR = 1.3) were significantly (P < .05) associated with hepatitis A-related hospitalization.

CONCLUSIONS

Our findings support current Advisory Committee on Immunization Practices recommendations to vaccinate all persons who use drugs, men who have sex with men, and persons experiencing homelessness against hepatitis A.

Susceptibility to Hepatitis A Virus Infection in the United States, 2007-2016

BACKGROUND

Despite national immunization efforts, including universal childhood hepatitis A (HepA) vaccination recommendations in 2006, hepatitis A virus (HAV)-associated outbreaks have increased in the United States. Unvaccinated or previously uninfected persons are susceptible to HAV infection, yet the susceptibility in the US population is not well known.

METHODS

Using National Health and Nutrition Examination Survey 2007-2016 data, we estimated HAV susceptibility prevalence (total HAV antibody negative) among persons aged ≥2 years. Among US-born adults aged ≥20 years, we examined prevalence, predictors, and age-adjusted trends of HAV susceptibility by sociodemographic characteristics. We assessed HAV susceptibility and self-reported nonvaccination to HepA among risk groups and the "immunization cohort" (those born in or after 2004).

RESULTS

Among US-born adults aged ≥20 years, HAV susceptibility prevalence was 74.1% (95% confidence interval, 72.9-75.3%) during 2007-2016. Predictors of HAV susceptibility were age group 30-49 years, non-Hispanic white/black, 130% above the poverty level, and no health insurance. Prevalences of HAV susceptibility and nonvaccination to HepA, respectively, were 72.9% and 73.1% among persons who reported injection drug use, 67.5% and 65.2% among men who had sex with men, 55.2% and 75.1% among persons with hepatitis B or hepatitis C, and 22.6% and 25.9% among the immunization cohort. Susceptibility and nonvaccination decreased over time among the immunization cohort but remained stable among risk groups.

CONCLUSIONS

During 2007-2016, approximately three-fourths of US-born adults remained HAV susceptible. Enhanced vaccination efforts are critically needed, particularly targeting adults at highest risk for HAV infection, to mitigate the current outbreaks.

Twitter Communication During an Outbreak of Hepatitis A in San Diego, 2016-2018

Objectives. To examine how and what information is communicated via social media during an infectious disease outbreak.Methods. In the context of the 2016 through 2018 hepatitis A outbreak in San Diego County, California, we used a grounded theory-based thematic analysis that employed qualitative and quantitative approaches to uncover themes in a sample of public tweets (n = 744) from Twitter, a primary platform used by key stakeholders to communicate to the public during the outbreak.Results. Tweets contained both general and hepatitis A-specific information related to the outbreak, restatements of policy and comments critical of government responses to the outbreak, information with the potential to shape risk perceptions, and expressions of concern regarding individuals experiencing homelessness and their role in spreading hepatitis A. We also identified misinformation and common channels of content driving themes that emerged in our sample.Conclusions. Public health professionals may identify real-time public risk perceptions and concerns via social media during an outbreak and target responses that fulfill the informational needs of those who seek direction and reassurance during times of uncertainty.

Rapid Salivary IgG Antibody Screening for Hepatitis A

Hepatitis A virus (HAV) is a common infection that is transmitted through the fecal-oral route, shed in the stool of infected individuals, and spread either by direct contact or by ingesting contaminated food or water. Each year, approximately 1.4 million acute cases are reported globally with a major risk factor for exposure being low household socioeconomic status. Recent trends show a decrease in anti-HAV antibodies in the general population, with concomitant increases in the numbers of HAV outbreaks. In line with a recreational water study, this effort aims to assess the prevalence of salivary IgG antibodies against HAV and subsequent incident infections (or immunoconversions) in visitors to a tropical beach impacted by a publicly owned treatment works (POTW). We applied a multiplex immunoassay to serially collected saliva samples gathered from study participants who recreated at Boquerón Beach, Puerto Rico. Analysis of assay results revealed an immunoprevalence rate of 16.17% for HAV with 1.43% of the cohort immunoconverting to HAV. Among those who immunoconverted, 10% reported chronic gastrointestinal symptoms and none experienced diarrhea. Tests on water samples indicated good water quality with low levels of fecal indicator bacteria; however, the collection and analysis of saliva samples afforded the ability to detect HAV infections in beachgoers. This rapid assay serves as a cost-effective tool for examining exposure to environmental pathogens and can provide critical information to policy makers, water quality experts, and risk assessment professionals seeking to improve and protect recreational water and public health.

Effectiveness of hepatitis A vaccination among people living with HIV in Taiwan: Is one dose enough?

BACKGROUND

Single dose hepatitis A virus (HAV) vaccine had been proven its efficacy in immunocompetent but not immunocompromised hosts. We aim to investigate the effectiveness of one dose versus 2 doses HAV vaccine among people living with HIV (PLHIV).

METHOD

We conducted a 1:1 single center retrospective case-control study for PLHIV in Northern Taiwan. Case patients were those who received single dose HAV vaccine and controls were those who completed standard 2 doses HAV vaccine. Nationwide campaign of single dose HAV vaccine had been practiced for high risk population including PLHIV and those who had newly diagnosed sexually transmitted diseases.

RESULTS

During February 2016 and December 2017, 90 cases received single dose HAV vaccine provided while the other 90 age-matched controls received 2 doses vaccine were enrolled. We found more injection drug users (22.22% vs. 1.11%, p < 0.0001), more co-infection with viral hepatitis C (28.89% vs. 5.56%, p < 0.0001), and history of syphilis infection (56.67% VS 30%, p = 0.0003) in single dose group than 2 doses group. Seroconversion rate at one year was significantly higher in 2 doses group (97.78% vs 56.67%, p < 0.0001). Among single dose group, people with hepatitis B or C virus co-infection (HBV: p = 0.02, aOR: 0.03, 95% CI: 0.002-0.55; HCV: p = 0.002, aOR: 0.22, 95% CI: 0.08-0.58) were less likely to achieve seropositivity, while those who had higher CD4 count at baseline and one year, had better response to vaccine.

CONCLUSION

Two doses HAV vaccine is necessary among PLHIV to achieve sustained seroresponse rather than single dose.

Disparities in hepatitis A virus (HAV) vaccination coverage among adult travelers to intermediate or high-risk countries: The role of birthplace and race/ethnicity

BACKGROUND

While the hepatitis A virus (HAV) vaccine is recommended for United States (US) travelers to endemic regions, vaccination rates are lower among non-US-born adults and some racial minority groups.

PURPOSE

We aimed to examine the relationship between birthplace, race and their interaction as predictors of self-reported HAV vaccination among adult travelers to high-risk countries (HRCs) through analysis of the National Health Interview Survey (NHIS), 2012-2015.

METHODS

The study included 36,872 US adult participants in the 2012-2015 NHIS who traveled to countries where HAV is endemic. The main outcome was self-reported HAV vaccination (≥2 doses). Complex survey methods were applied to all models to provide statistical estimates that were representative of US adults. Multivariable logistic regression models adjusting for demographic, socioeconomic, medical, and access-to-care characteristics were fitted to examine the association between birthplace, race, race-by-birthplace (for interaction) and vaccination status.

RESULTS

For adult travelers to HRCs, the adjusted odds ratio (AOR) of HAV vaccination was lower for non-US-born compared to US-born adults, AOR 0.86 (95% CI; 0.76, 0.98). For Hispanics, the AOR of HAV vaccination was 0.80 (95% CI; 0.70, 0.91) as compared to non-Hispanic-Whites. Furthermore, a significant qualitative interaction between birthplace and race was found (P-value 0.0005). Among non-Hispanic Blacks, the adjusted odds of HAV vaccination for non-US-born adults were 1.35 (95% CI; 1.06, 1.72) times the odds for US-born adults. In contrast, the AORs of HAV vaccination of non-US-born versus US-born adults were 36% (95% CI; 17%, 51%) and 30% (95% CI; 12%, 44%), lower for Asians and Hispanics, respectively.

CONCLUSIONS

The association between birthplace and HAV vaccination status differs by race among travelers to HRCs, with US-born non-Hispanic Black and non-US-born Asian and Hispanic adults having lower odds of vaccination. Health care resources should be focused on these target populations to improve travel vaccination compliance.

Emerging Threat: Changing Epidemiology of Hepatitis A and Acute Kidney Injury

In the past decade, hepatitis A has been considered a rare disease in the United States, largely due to targeted vaccination of at-risk children. Evolving epidemiology has resulted in decreasing immunity and increasing hepatitis A infections among adults who are more likely to experience severe disease. A surge in outbreaks has been noted in the past 2 years, resulting in a high volume of hepatitis A related hospitalizations and complications in otherwise healthy individuals. The traditional understanding that acute kidney injury is a rare extrahepatic manifestation is being challenged by the resurgence of hepatitis A in a more vulnerable population. This review examines the epidemiologic factors that contributed to current public health concern and the association between hepatitis A and acute kidney injury.

Abnormal Liver Enzymes

Abnormal liver enzymes are frequently encountered in primary care offices and hospitals and may be caused by a wide variety of conditions, from mild and nonspecific to well-defined and life-threatening. Terms such as "abnormal liver chemistries" or "abnormal liver enzymes," also referred to as transaminitis, should be reserved to describe inflammatory processes characterized by elevated alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase. Although interchangeably used with abnormal liver enzymes, abnormal liver function tests specifically denote a loss of synthetic functions usually evaluated by serum albumin and prothrombin time. We discuss the entities that most commonly cause abnormal liver enzymes, specific patterns of enzyme abnormalities, diagnostic modalities, and the clinical scenarios that warrant referral to a hepatologist.

Epidemiology and Transmission of Hepatitis A Virus and Hepatitis E Virus Infections in the United States

There are many similarities in the epidemiology and transmission of hepatitis A virus (HAV) and hepatitis E virus (HEV) genotype (gt)3 infections in the United States. Both viruses are enterically transmitted, although specific routes of transmission are more clearly established for HAV than for HEV: HAV is restricted to humans and primarily spread through the fecal-oral route, while HEV is zoonotic with poorly understood modes of transmission in the United States. New cases of HAV infection have decreased dramatically in the United States since infant vaccination was recommended in 1996. In recent years, however, outbreaks have occurred among an increasingly susceptible adult population. Although HEV is the most common cause of acute viral hepatitis in developing countries, it is rarely diagnosed in the United States.

Very low prevalence of anti-HAV in Japan: high potential for future outbreak

Since the early 21^st century, almost all developed countries have had a very low hepatitis A virus antibody (anti-HAV) sero-prevalence profile, as sanitation conditions and health care facilities have been optimized to a universal standard. There has not been a report on anti-HAV prevalence among a large scale population in Japan since 2003. Therefore, this study aimed to investigate the current HAV status among the general population in Hiroshima. From each age and sex specific group, a total of 1,200 samples were randomly selected from 7,682 stocked serum samples from residents' and employees' annual health check-ups during 2013-2015. Total anti-HAV was detected using Chemiluminescent Enzyme Immunoassay. The overall anti-HAV sero-prevalence was 16.8%. In both males and females, anti-HAV prevalence among individuals between 20-59 years of age was as low as 0.0-2.0%, whilst that among 70 s was as high as 70.0-71.0%. A large number of residents aged under 60 are now susceptible to HAV infection. The cohort reduction trend of anti-HAV in Japan exposes the high possibility of mass outbreak in the future. HAV vaccine especially to younger generation and high risk population may prevent outbreak in Japan.

Distribution of hepatitis A antibodies in US blood donors

BACKGROUND

Recently, there has been an increase in the number of hepatitis A outbreaks in the United States. Although the presence of hepatitis A virus (HAV) RNA in blood donors is known to be low, HAV antibody prevalence in this population is unknown.

STUDY DESIGN AND METHODS

Samples from 5001 US blood donors collected primarily in the midwestern United States in 2015 were tested for the presence of HAV IgG antibodies using chemiluminescent microparticle immunoassays on the ARCHITECT platform (Abbott Laboratories).

RESULTS

The overall prevalence of IgG anti-HAV was 60%. Only one specimen was IgM anti-HAV positive, for an incidence of 0.02%. IgG anti-HAV prevalence among donors aged 16 to 19 years was 67%, decreased to 54% among donors aged 40 to 49 years and increased to 70% among donors aged 80 to 93 years. No differences were seen by sex with overall IgG anti-HAV prevalence of 61% and 60% for males and females, respectively. Among the five states (Illinois, Indiana, Kansas, Kentucky, and Missouri) with the highest number of donors tested, IgG anti-HAV prevalence in Missouri (65%) was significantly higher (p <0.01) than that in Illinois (52%) or Kentucky (59%). No other significant differences between states were noted.

CONCLUSION

This study demonstrates the overall high rates of IgG anti-HAV in US blood donors, with the low associated risk of HAV transfusion transmission likely the result of low incidence and effective vaccination.

Hepatitis A vaccination coverage among adolescents (13-17 years) in the United States, 2008-2016

BACKGROUND

The hepatitis A (HepA) vaccine was recommended by the Advisory Committee on Immunization Practices (ACIP) incrementally from 1996 to 1999. In 2006, HepA vaccine was recommended (1) universally for children aged 12-23 months, (2) for persons who are at increased risk for infection, or (3) for any person wishing to obtain immunity. Catch-up vaccination can be considered.

OBJECTIVE

To assess HepA vaccine coverage among adolescents and factors independently associated with vaccination administration in the US.

METHODS

The 2008-2016 National Immunization Survey-Teen was utilized to determine 1 and ≥2 dose HepA vaccination coverage among adolescents aged 13-17 years. Factors associated with HepA vaccine series initiation (1 dose) were determined by bivariate and multivariable analyses. Data were stratified by state groups based on ACIP recommendation: universal child vaccination recommended since 1999 (group 1); child vaccination considered since 1999 (group 2); universal child vaccination recommendation since 2006 (group 3).

RESULTS

In 2016, national vaccination coverage for 1 and ≥2 doses of HepA vaccine among adolescents was 73.9% and 64.4%, respectively. Nationally, a 40 percentage point increase in vaccination coverage occurred among adolescents born in 1995 compared to adolescents born in 2003. Nationally, the independent factors associated with increased vaccine initiation was race/ethnicity (Hispanic, American Indian/Alaskan Native, Asian), military payment source and provider recommendation for HepA vaccination (2008-2013). Living in a suburban or rural region, living in poverty (level <1.33-5.03), and absence of state daycare or school HepA requirement were common factors associated with decreased likelihood of vaccine initiation.

CONCLUSIONS

Efforts to increase HepA vaccine coverage in adolescents in all regions of the country would strengthen population protection from hepatitis A virus (HAV).

The effectiveness and limitation of the national childhood hepatitis A vaccination program in the Republic of Korea: Findings from the Korean National Health and Nutrition Examination Survey (KNHANES), 2015

Background

Vaccination for hepatitis A virus (HAV) has been implemented as one of the national vaccination programs despite the epidemiological transition of HAV in the Republic of Korea. While the national HAV vaccination program is largely associated with the shift of socioeconomic trend in the country, concerns have been raised on the effectiveness of the HAV immunization. The objective of this study was to examine the epidemiological trend of HAV and assess the effectiveness of the nationwide HAV vaccination policy based on a nationally representative sample of the Korean population collected in 2015.

Methods

We analyzed anti-HAV of 5,856 respondents aged ≥10 years collected from Korean National Health and Nutrition Examination Survey (KNHANES) data in 2015. We estimated age-adjusted anti-HAV prevalence by sociodemographic and other characteristics. We evaluated the factors associated with anti-HAV positivity among each age group (10–19, 20–29, 30–45 and over 45 years old).

Results

The prevalence of anti-HAV among adults aged ≥10 years was 72.5% (95% confidence interval, CI, 73.7–71.4) in 2015. The lowest age-specific prevalence was among adults aged 20–29 years with 11.9% (95% CI 9.3–15.1%). The prevalence of anti-HAV among those aged 10–14 and 15–19 years was 59.7% (95% CI 52.7–66.4) and 24.0% (95% CI 19.5–29.3), respectively. The prevalence of anti-HAV among adults aged between 30 and 44 years rapidly increased from below 20% to above 90%. The prevalence of anti-HAV among adults aged ≥45 years was 97.8% (95% CI 96.0–97.6). Factors significantly associated with anti-HAV positivity among those aged 10–19 years old were young age, higher house income and high influenza vaccination rate. Compared to the respondents aged 10–19 years (those who were subject to the national childhood vaccine recommendation), those aged 20–29 years (those who were not subject to the recommendation) had low adjusted odds ratio (OR, 0.52 95% CI 0.34–.81 P-value = 0.004) for anti-HAV positivity.

Conclusions

The age-adjusted anti-HAV prevalence showed a U-shaped association, implying the high dependence of anti-HAV prevalence on age and the epidemiological shift. The inclusion of the hepatitis A vaccine into the national immunization recommendation was effective shown by the increase of immunity in the general population. However, the vaccination rate was low in the low-income group. Young adults aged 20–39 years may benefit from inclusion in the HAV vaccination program due to the significantly low vaccination rate.

Type A viral hepatitis: A summary and update on the molecular virology, epidemiology, pathogenesis and prevention

Although epidemic jaundice was well known to physicians of antiquity, it is only in recent years that medical science has begun to unravel the origins of hepatitis A virus (HAV) and the unique pathobiology underlying acute hepatitis A in humans. Improvements in sanitation and the successful development of highly efficacious vaccines have markedly reduced the worldwide prevalence and incidence of this enterically-transmitted infection over the past quarter century, yet the virus persists in vulnerable populations and remains a common cause of food-borne disease outbreaks in economically-advantaged societies. Reductions in the prevalence of HAV have led to increases in the median age at which infection occurs, often resulting in more severe disease in affected persons and paradoxical increases in disease burden in some developing nations. Here, we summarize recent advances in the molecular virology of HAV, an atypical member of the Picornaviridae family, survey what is known of the pathogenesis of hepatitis A in humans and the host-pathogen interactions that typify the infection, and review medical and public health aspects of immunisation and disease prevention.

Physician Knowledge and Attitudes About Hepatitis A and Current Practices Regarding Hepatitis A Vaccination Delivery

OBJECTIVE

To assess physicians': 1) knowledge and attitudes about hepatitis A disease and hepatitis A (HepA) vaccine, 2) child care and school HepA vaccine mandates, 3) practices related to HepA vaccine delivery, 4) factors associated with strongly recommending HepA vaccine to all 1- to 2-year-olds, and 5) feasibility of implementing HepA catch-up vaccination at health maintenance visits.

METHODS

A national survey was conducted among representative networks of pediatricians and family medicine physicians (FMs) from March to June, 2014 via e-mail or mail on the basis of provider preference.

RESULTS

Response rates were 81% (356 of 440) among pediatricians and 75% (348 of 464) among FMs. Less than 50% correctly identified that hepatitis A virus (HAV) infection is usually asymptomatic in young children and that morbidity from HAV disease increases with age. Ninety-two percent of pediatricians and 59% of FMs strongly recommend HepA vaccine for all 1- to 2-year-olds. In addition to practice specialty, belief that HepA vaccine is required for kindergarten enrollment was the most robust predictor of strong physician recommendation.

CONCLUSIONS

Gaps in knowledge regarding HAV infection and hepatitis A recommendations and lack of a strong recommendation for routine HepA vaccination of young children among FMs likely contribute to suboptimal coverage. Closing knowledge gaps and addressing barriers that prevent all physicians from strongly recommending HepA vaccine to 1- to 2-year-olds could help increase HepA vaccine coverage and ultimately improve population protection against HAV infection.

Clinical characteristics of acute hepatitis A outbreak in Taiwan, 2015-2016: observations from a tertiary medical center

Background

Acute hepatitis A is a fecal-oral transmitted disease related to inadequate sanitary conditions. In addition to its traditional classification, several outbreaks in the men who have sex with men (MSM) population have resulted in acute hepatitis A being recognized as a sexually transmitted disease. However, few studies have clarified the clinical manifestations in these outbreaks involving the MSM population.

Methods

Beginning in June 2015, there was an outbreak of acute hepatitis A involving the MSM population in Northern Taiwan. We conducted a 15-year retrospective study by recruiting 207 patients with the diagnosis of acute hepatitis A that included the pre-outbreak (January 2001 to May 2015) and outbreak (June 2015 to August 2016) periods in a tertiary medical center in Northern Taiwan. Using risk factors, comorbidities, presenting symptoms, laboratory test results and imaging data, we aimed to evaluate the clinical significance of acute hepatitis A in the MSM population, where human immunodeficiency virus (HIV) coinfection is common.

Results

There was a higher prevalence of reported MSM (p < 0.001), HIV (p < 0.001) and recent syphilis (p < 0.05) coinfection with acute hepatitis A during the outbreak period. The outbreak population had more prominent systemic symptoms, was more icteric with a higher total bilirubin level (p < 0.05) and had a 7-times higher tendency (p < 0.05) to have a hepatitis A relapse.

Conclusions

The clinical course of acute hepatitis A during an outbreak involving the MSM and HIV-positive population is more symptomatic and protracted than in the general population.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-017-2555-x) contains supplementary material, which is available to authorized users.

The Financial Burden of Public Health Responses to Hepatitis A Cases Among Food Handlers, 2012-2014

When food handlers become ill with hepatitis A virus (HAV) infection, state and local health departments must assess the risk of HAV transmission through prepared food and recommend or provide postexposure prophylaxis (PEP) for those at risk for HAV infection. Providing PEP (eg, hepatitis A [HepA] vaccine or immunoglobulin), however, is costly. To describe the burden of these responses on state and local health departments, we determined the number of public health responses to HAV infections among food handlers by reviewing public internet sources of media articles. We then contacted each health department to collect data on whether PEP was recommended to food handlers or restaurant patrons, the number of PEP doses given, the number of HepA vaccine or immunoglobulin doses given as PEP, and the mean number of health department person-hours required for the response. Of 32 public health responses identified from Twitter, HealthMap, and Google alerts from January 1, 2012, to December 31, 2014, a total of 27 (84%) recommended PEP for other food handlers or restaurant patrons or both. Per public health response, the mean cost per dose of the HepA vaccine or immunoglobulin was $34 139; the mean personnel cost per response was $7329; and the total mean cost of each response was $41 468. PEP is expensive. Less aggressive approaches to PEP, such as limiting PEP to fellow food handlers in nonoutbreak situations, should be considered in the postvaccination era. HepA vaccine for PEP provides long-term immunity and can be used when immunoglobulin is unavailable or cannot be administered within 14 days of exposure to HAV.

Impact of the national targeted Hepatitis A immunisation program in Australia: 2000-2014

In November 2005, hepatitis A vaccine was funded under the Australian National Immunisation Program for Aboriginal and Torres Strait Islander (Indigenous) children aged 12-24months in the targeted jurisdictions of Queensland, South Australia, Western Australia and the Northern Territory. We reviewed the epidemiology of hepatitis A from 2000 to 2014 using data from the Australian National Notifiable Diseases Surveillance System, the National Hospital Morbidity Database, and Australian Bureau of Statistics causes-of-death data. The impact of the national hepatitis A immunisation program was assessed by comparison of pre-vaccine (2000-2005) and post-vaccine time periods (2006-2014), by age group, Indigenous status and jurisdiction using incidence rate ratios (IRR) per 100,000 population and 95% confidence intervals (CI). The national pre-vaccine notification rate in Indigenous people was four times higher than the non-Indigenous rate, and declined from 8.41 per 100,000 (95% CI 5.03-11.79) pre-vaccine to 0.85 per 100,000 (95% CI 0.00-1.99) post-vaccine, becoming similar to the non-Indigenous rate. Notification and hospitalisation rates in Indigenous children aged <5years from targeted jurisdictions declined in the post-vaccine period when compared to the pre-vaccine period (notifications: IRR=0.07; 95% CI 0.04-0.13; hospitalisations: IRR=0.04; 95% CI 0.01-0.16). As did notification rates in Indigenous people aged 5-19 (IRR=0.08; 95% CI 0.05-0.13) and 20-49years (IRR=0.06; 95% CI 0.02-0.15) in targeted jurisdictions. For non-Indigenous people from targeted jurisdictions, notification rates decreased significantly in children aged <5years (IRR 0.47; 95% CI 0.31-0.71), and significantly more overall (IRR=0.43; 95% CI 0.39-0.47) compared to non-Indigenous people from non-targeted jurisdictions (IRR=0.60; 95% CI 0.56-0.64). The national hepatitis A immunisation program has had a significant impact in the targeted population with relatively modest vaccine coverage, with evidence suggestive of substantial herd protection effects.

Progress Toward Eliminating Hepatitis A Disease in the United States

Hepatitis A virus (HAV) disease disproportionately affects adolescents and young adults, American Indian/Alaska Native and Hispanic racial/ethnic groups, and disadvantaged populations. During 1996-2006, the Advisory Committee on Immunization Practices (ACIP) made incremental changes in hepatitis A (HepA) vaccination recommendations to increase coverage for children and persons at high risk for HAV infection. This report examines the temporal association of ACIP-recommended HepA vaccination and disparities (on the absolute scale) in cases of HAV disease and on seroprevalence of HAV-related protection (measured as antibody to HAV [anti-HAV]). ACIP-recommended childhood HepA vaccination in the United States has eliminated most absolute disparities in HAV disease by age, race/ethnicity, and geographic area with relatively modest ≥1-dose and ≥2-dose vaccine coverage. However, the increasing proportion of cases of HAV disease among adults with identified and unidentified sources of exposure underscores the importance of considering new strategies for preventing HAV infection among U.S. adults. For continued progress to be made toward elimination of HAV disease in the United States, additional strategies are needed to prevent HAV infection among an emerging population of susceptible adults. Notably, HAV infection remains endemic in much of the world, contributing to U.S. cases through international travel and the global food economy.