Hepatitis A Vaccination Coverage Among People With Chronic Liver Disease in England (HEALD): Protocol for a Retrospective Cohort Study

BACKGROUND

Hepatitis A outbreaks in the United Kingdom are uncommon. Most people develop mild to moderate symptoms that resolve, without sequelae, within months. However, in high-risk groups, including those with underlying chronic liver disease (CLD), hepatitis A infection can be severe, with a higher risk of mortality and morbidity. The Health Security Agency and the National Institute of Health and Care Excellence recommend preexposure hepatitis A vaccination given in 2 doses to people with CLD, regardless of its cause. There are currently no published reports of vaccination coverage for people with CLD in England or internationally.

OBJECTIVE

This study aims to describe hepatitis A vaccination coverage in adults with CLD in a UK primary care setting and compare liver disease etiology, sociodemographic characteristics, and comorbidities in people who are and are not exposed to the hepatitis A vaccine.

METHODS

We will conduct a retrospective cohort study with data from the Primary Care Sentinel Cohort of the Oxford-Royal College of General Practitioners Clinical Informatics Digital Hub database, which is nationally representative of the English population. We will include people aged 18 years and older who have been registered in general practices in the Research and Surveillance Centre network and have a record of CLD between January 1, 2012, and December 31, 2022, including those with alcohol-related liver disease, chronic hepatitis B, chronic hepatitis C, nonalcohol fatty liver disease, Wilson disease, hemochromatosis, and autoimmune hepatitis. We will carefully curate variables using the Systematized Nomenclature of Medicine Clinical Terms. We will report the sociodemographic characteristics of those who are vaccinated. These include age, gender, ethnicity, population density, region, socioeconomic status (measured using the index of multiple deprivation), obesity, alcohol consumption, and smoking. Hepatitis A vaccination coverage for 1 and 2 doses will be calculated using an estimate of the CLD population as the denominator. We will analyze the baseline characteristics using descriptive statistics, including measures of dispersion. Pairwise comparisons of case-mix characteristics, comorbidities, and complications will be reported according to vaccination status. A multistate survival model will be fitted to estimate the transition probabilities among four states: (1) diagnosed with CLD, (2) first dose of hepatitis A vaccination, (3) second dose of hepatitis A vaccination, and (4) death. This will identify any potential disparities in how people with CLD get vaccinated.

RESULTS

The Research and Surveillance Centre population comprises over 8 million people. The reported incidence of CLD is 20.7 cases per 100,000. International estimates of hepatitis A vaccine coverage vary between 10% and 50% in this group.

CONCLUSIONS

This study will describe the uptake of the hepatitis A vaccine in people with CLD and report any disparities or differences in the characteristics of the vaccinated population.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

PRR1-10.2196/51861.

Dynamic Changes in Hepatitis A Immunity in Regions with Different Vaccination Strategies and Different Vaccination Coverage

The data on hepatitis A virus (HAV) seroprevalence are critical for the implementation of a universal mass vaccination (UMV) strategy. The latter has not been implemented in Russia; however, regional child vaccination programs have been adopted in some parts of the country. The aim of this study is to assess changes in HAV immunity within the last decade in regions of Russia with different vaccination strategies and different vaccination coverage rates. In regions where UMV has not been implemented and HAV vaccination coverage rates do not exceed the national average, the 50% seroprevalence threshold has shifted in the Moscow region from people aged under 40 years in 2008 to people aged over 59 years in 2020, and from people aged under 30 years to people aged over 40 years in the Khabarovsk region. In two regions (Yakutia and Sverdlovsk), a two-dose-based UMV scheme has been in place since 2011 and 2003, respectively, and in Tuva single-dose child immunization was launched in 2012. These regional programs have resulted in a significant increase in HAV seroprevalence in children and adolescents. In Yakutia, 50% herd immunity had been achieved by 2020 in age groups under 20 years, compared to 20−30% seroprevalence rates in 2008. In the Sverdlovsk region, HAV immunity has increased to >65% over the decade in children aged over 10 years, adolescents and young adults, whereas it declined in older age groups. However, a three-fold drop in HAV immunity has occurred in children under 10 years of age, reflecting a significant decline in vaccination coverage. In Tuva, HAV immunity rates in children under 10 years old increased two-fold to exceed 50% by 2020. These data suggest that UMV should be implemented on a national level. Measures to control vaccination coverage and catch-up vaccination campaigns are recommended in order to maintain the effectiveness of existing HAV vaccination programs.

In-hospital post-transplant acute hepatitis A viral (HAV) infection in a liver transplant recipient who was HAV seropositive pre-transplant

Acute hepatitis A viral (HAV) infection is rare in the liver transplant population due to recommended pre-transplant vaccinations. We report a case of acute hepatitis A infection in a liver transplant recipient. This individual had immunity to hepatitis A with protective IgG antibodies and presented with abnormal liver biochemistry in the post-transplant in-patient setting. Hepatitis A infection was confirmed by positive HAV IgM whereas other etiologies, including acute cellular rejection, were ruled out by laboratory tests and liver biopsies. He was treated conservatively with supportive care and liver enzymes recovered to normal baseline. Despite adequate pre-transplant immunity, in the post-transplant setting there may be loss of protective immunity due to profound immunosuppression and hence hepatitis A should remain an important differential diagnosis in the setting of acute hepatitis.

Hepatitis A, B, and A/B vaccination series completion among US adults: A claims-based analysis

Hepatitis A and B disease burden persists in the US. We assessed hepatitis A and hepatitis B vaccination series completion rates among 350,240 commercial/Medicare and 12,599 Medicaid enrollees aged ≥19 years. A vaccination series was considered as completed provided that the minimum interval between doses, as defined by the CDC, and the minimum number of doses were reached. We stratified completion rates by vaccine type (i.e. monovalent or bivalent) at initial vaccination for each cohort. In the commercial/Medicare cohort, the series completion rate was 32.0% for hepatitis A and 39.6% for hepatitis B among those who initiated with a monovalent vaccine, and it was 36.2% for hepatitis A and 48.9% for hepatitis B among those who initiated with a bivalent vaccine. In the Medicaid cohort, the series completion rate was 21.0% for hepatitis A and 24.0% for hepatitis B among those who initiated with a monovalent vaccine, and it was 19.0% for hepatitis A and 24.6% for hepatitis B among those who initiated with a bivalent vaccine. In conclusion, hepatitis A and B vaccination series completion rates were low, and appeared to be lower among Medicaid than among commercial/Medicare enrollees. Commercial/Medicare enrollees who initiated with a bivalent vaccine had higher series completion rates than those who initiated with monovalent vaccines – an observation that was not made among Medicaid enrollees.

Response to Hepatitis A Vaccination in Immunocompromised Travelers

BACKGROUND

Hepatitis A vaccines are highly immunogenic in healthy patients, but there is uncertainty about their immunogenicity in immunocompromised patients.

METHODS

Our study included immunocompromised patients who received 1 or 2 hepatitis A vaccinations between January 2011 and June 2013. We assessed factors that influenced the serologic response to vaccination. We performed a literature review of previous studies on hepatitis A vaccination in immunocompromised patients.

RESULTS

Of 85 immunocompromised patients, 65 used immunosuppressive drugs, 13 had received stem cell transplants, and 7 were infected with human immunodeficiency virus. After vaccination, 65 of 85 (76.5%) developed antibodies. Tumor necrosis factor α blocker use was associated with better serologic responses than other immunosuppressive drugs. Female patients were more compliant than male patients with postvaccination antibody titer measurements. In 11 relevant studies, antibody responses after the first and second vaccination averaged 37% and 82%, respectively. Factors that negatively influenced serologic response rates were high doses of immunosuppressive drugs, fewer hepatitis A vaccinations, and a short interval between vaccination and antibody measurement.

CONCLUSIONS

Immunocompromised patients showed moderate to good serologic responses to hepatitis A vaccination, but may need more time to develop immunity. Tumor necrosis factor α blocker use was associated with better antibody responses than other drugs. Specifically, male patients should be motivated to return for antibody titer measurements.

Effectiveness of 10-year vaccination (2001-2010) on Hepatitis A in Tianjin, China

Vaccination is an effective strategy to prevent and control the transmission of hepatitis A. Hepatitis A immunization program has been taken into effect since 2001 in Tianjin, China. This study evaluated the effectiveness of strategies in the prevention and control of hepatitis A. Data of serological survey, annual hepatitis A incidence, immunization coverage and the positive rate of hepatitis A IgG before and after the immunization program in residents under 15 years old were used to do the analysis. The results indicated that hepatitis A vaccine induced a striking decrease of hepatitis A incidence and a significant increase in the positive rate of anti-HAV IgG among the children younger than 15 years old. Hepatitis A vaccination in children was proved to be effective in the prevention and control of hepatitis A in Tianjin, China.

Hepatitis A Virus among Drug Users and the Role of Vaccination: A Review

In countries with advanced economies better health and hygiene conditions, along with the introduction, in some cases, of global vaccination, have relegated most viral hepatitis to marginal social groups and, in particular, drug users (DUs). The availability of safe and effective vaccines for hepatitis A virus (HAV) and B (HBV) may play a major role in combating this phenomenon. Despite the availability of a safe and effective vaccine for over a decade and the recommendations of international health organizations, vaccinations against HAV among DUs are not as widely known and available as are HBV vaccinations. The purpose of this review article is to present the most significant data in the literature on the prevalence of HAV among DUs and the role of targeted vaccination. To our knowledge, the present article is the first to solely deal with vaccination against HAV in DUs. Immunization after the administration of anti-HAV vaccine has been demonstrated in DUs even if they have responded significantly less than either the general population or carriers of chronic liver disease. All the vaccines were well tolerated and adherence to the vaccine schedule was good. Further studies are needed to optimize the timing and doses of vaccine to be administered to DUs, especially to assess adherence and antibody persistence. Vaccination campaigns are feasible among DUs and have proven to be highly cost-effective.