A Description of a Health System's Emergency Department Patients Who Were Part of a Large Hepatitis A Outbreak

The Burden of Hepatitis A Outbreaks in the United States: Health Outcomes, Economic Costs, and Management Strategies

BACKGROUND

Hepatitis A (HepA) vaccines are recommended for US adults at risk of HepA. Ongoing United States (US) HepA outbreaks since 2016 have primarily spread person-to-person, especially among at-risk groups. We investigated the health outcomes, economic burden, and outbreak management considerations associated with HepA outbreaks from 2016 onwards.

METHODS

A systematic literature review was conducted to assess HepA outbreak-associated health outcomes, health care resource utilization (HCRU), and economic burden. A targeted literature review evaluated HepA outbreak management considerations.

RESULTS

Across 33 studies reporting on HepA outbreak-associated health outcomes/HCRU, frequently reported HepA-related morbidities included acute liver failure/injury (n = 6 studies of 33 studies) and liver transplantation (n = 5 of 33); reported case fatality rates ranged from 0% to 10.8%. Hospitalization rates reported in studies investigating person-to-person outbreaks ranged from 41.6% to 84.8%. Ten studies reported on outbreak-associated economic burden, with a national study reporting an average cost of over $16 000 per hospitalization. Thirty-four studies reported on outbreak management; challenges included difficulty reaching at-risk groups and vaccination distrust. Successes included targeted interventions and increasing public awareness.

CONCLUSIONS

This review indicates a considerable clinical and economic burden of ongoing US HepA outbreaks. Targeted prevention strategies and increased public awareness and vaccination coverage are needed to reduce HepA burden and prevent future outbreaks.

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.

Vaccine-preventable diseases other than tuberculosis, and homelessness: A scoping review of the published literature, 1980 to 2020

BACKGROUND

Homelessness may result in the breakdown of regular health services, including routine vaccination programmes. A scoping review was conducted to describe vaccine-preventable diseases (VPD) other than tuberculosis in people experiencing homelessness (PEH).

METHODS

We followed the Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR). We searched peer-reviewed literature published in English, French, Spanish or Portuguese reporting the outbreak of VPD or VPD prevalence in both infant and adult homeless populations published between 1980 and 2020, using PubMed/Medline, SciELO, Google Scholar, and Web of Science databases. Relevant information from the studies was charted in Microsoft Excel and results were summarised using a descriptive analytical method.

RESULTS

Eighty-one articles were included. A high prevalence of past hepatitis B virus (HBV) and hepatitis A virus (HAV) infections were observed through serosurveys, mostly in high income countries or high-middle income countries (USA, Canada, France, Iran or Brazil). Ten outbreaks of HAV infection were also reported, with lethality rates ranging from 0 to 4.8%. The studies identified numerous risk factors positively associated with HBV infection, including older age, homosexual or bisexual practice, injected drug use (IDU), and, with HAV infection including IDU, having sexual partner(s) with a history of unspecified hepatitis, insertive anal penetration, or originating from a country with a high prevalence of anti-HAV antibody. Eleven outbreaks of pneumococcal infection affecting PEH were reported in Canada and USA, with lethality rates from 0 to 15.6%. Six diphtheria outbreaks were reported. Vaccination status was rarely documented in these studies.

CONCLUSIONS

The literature suggests that homeless populations generally experience a high VPD burden suggesting the need for a national vaccination programme and planning for delivering vaccines in this population.

Emergency Department-based Hepatitis A Vaccination Program in Response to an Outbreak

INTRODUCTION

The Philadelphia Department of Public Health (PDPH) declared a public health emergency due to hepatitis A in August 2019. Our emergency department (ED) serves a population with many of the identified risk factors for hepatitis A transmission. This study examines the impact of an ED-based hepatitis A vaccination program, developed in partnership with the PDPH, on incidence of hepatitis A infection and hospital admission.

METHODS

We conducted a retrospective review of all ED visits in the 12-week period centered around the implementation of the ED-based hepatitis A vaccination program. All adult patients presenting to the ED were offered vaccination, with vaccines supplied free of charge by the PDPH. We compared the incidence of diagnosis and of hospital admission for treatment of hepatitis A before and after implementation of the program.

RESULTS

There were 10,033 total ED visits during the study period, with 5009 of them prior to the implementation of the vaccination program and 5024 after implementation. During the study period, 669 vaccines were administered. Before the vaccination program began, 73 patients were diagnosed with hepatitis A, of whom 67 were admitted. After implementation of the program, 38 patients were diagnosed with hepatitis A, of whom 31 were admitted.

CONCLUSION

A partnership between an ED and the local public health department resulted in the vaccination of 669 patients in six weeks in the midst of an outbreak of a vaccine-preventable illness, with a corresponding drop in ED visits and hospital admission for acute hepatitis A.

Cost-effectiveness of a comprehensive immunization program serving high-risk, uninsured adults

Despite the numerous social and economic benefits of vaccination, adult immunization rates fall far short of recommended levels costing the United States $9 billion annually in health care expenditures and reduced productivity. While it is well recognized that childhood immunization is highly cost-effective, the economic impact of adult immunization programs varies by disease and is influenced by population demographics. This study aimed to assess the cost-effectiveness of a comprehensive adult immunization program serving high-need populations delivered by a local health department (LHD) in partnership with community organizations. We modeled incremental cost-effectiveness taking the payer perspective of each vaccine separately in simulated cohorts of 100,000 over a 20-year horizon using data provided by the LHD and data from the published literature. We adjusted the results to align with actual program delivery and used them to estimate an incremental cost-effectiveness ratio (ICER) for the entire program. We assessed the effects of varying our base model parameters in univariate sensitivity analyses. We discounted benefits and life years saved (LYS) at 3% and adjusted results to 2016 US$. Four of seven disease models were cost-effective (using a $100,000 CE threshold) with ICERS ranging from $14,260 to $79,022/LYS. Sensitivity analyses did not substantially impact the results. The ICER for program as a whole was $67,940/LYS. A community-delivered comprehensive immunization program serving uninsured, low income, high-risk adults is a cost-effective investment even when most do not receive the full regimen of some vaccines.