Widespread Hepatitis A Outbreaks Associated with Person-to-Person Transmission - United States, 2016-2020.

Hepatitis A is a vaccine-preventable disease typically acquired through fecal-oral transmission. Hepatitis A virus (HAV) infection rates in the United States declined approximately 97% during 1995-2015 after the introduction and widespread pediatric use of hepatitis A vaccines (1). Since 2016, hepatitis A outbreaks have been reported in 37 states, involving approximately 44,650 cases, 27,250 hospitalizations, and 415 deaths as of September 23, 2022 (2). A report describing early outbreaks in four states during 2017 noted that most infections occurred among persons reporting injection or noninjection drug use or experiencing homelessness; this finding signaled a shift in HAV infection epidemiology from point-source outbreaks associated with contaminated food to large community outbreaks associated with person-to-person transmission (3). CDC analyzed interim data from 33 outbreak-affected states to characterize demographic, risk factor, and clinical outcome data from 37,553 outbreak-associated hepatitis A cases reported during August 1, 2016-December 31, 2020. Among persons with available risk factor or clinical outcome information, 56% reported drug use, 14% reported experiencing homelessness, and 61% had been hospitalized; 380 outbreak-associated deaths were reported. The most effective means to prevent and control hepatitis A outbreaks is through hepatitis A vaccination, particularly for persons at increased risk for HAV infection (4). The epidemiologic shifts identified during these outbreaks led to a 2019 recommendation by the Advisory Committee on Immunization Practices (ACIP) for vaccination of persons experiencing homelessness and reinforcement of existing vaccination recommendations for persons who use drugs (4). Substantial progress in the prevention and control of hepatitis A has been made; the number of outbreak-affected states has been reduced from 37 to 13 (2). Increased hepatitis A vaccination coverage, particularly through implementation of successful, nontraditional vaccination strategies among disproportionately affected populations (5), is needed to continue progress in halting current outbreaks and preventing similar outbreaks in the future.

Increase in Hepatitis A Cases Linked to Imported Strains to Rio de Janeiro, Brazil: A Cross-Sectional Study.

This study aims to evaluate the epidemiological and molecular features associated with HAV transmission in adults in Rio de Janeiro during a period of increased registered cases of HAV (2017-2018). Socio-epidemiological data and serum samples from anti-HAV IgM+ individuals were obtained. HAV RNA was RT-PCR amplified and sequenced for further phylogenetic and phylogeographic analyses. From fifty-two HAV IgM+ individuals, most were men (78.85%; p = 0.024), aged 20-30 years old (84.61%; p < 0.001), resided in the Rio de Janeiro north zone (31/52; 59.62%; p = 0.001), and are men who have sex with men (MSM) (57.69%; p = 0.002). Sexual practices were more frequent (96%) than others risk factors (food-borne (44%), water-borne (42.31%), and parenteral (34.62%)). Individuals who traveled to endemic regions had a 7.19-fold (1.93-36.04; p < 0.01) increased risk of HAV. Phylogenetic analysis revealed four distinct clades of subgenotype IA, three of them comprised sequences from European/Asian MSM outbreaks and one from Brazilian endemic strains. Bayesian Inference showed that the imported strains were introduced to Brazil during large mass sportive events. Sexual orientation and sexual practices may play a role in acquiring HAV infection. Public policies targeting key populations must be implemented to prevent further dissemination of HAV and other STIs.

Hepatitis A.

Hepatitis A is a common viral infection worldwide that is transmitted via the fecal-oral route. The incidence of infection in the United States decreased by more than 90% after an effective vaccine was introduced, but the number of cases has been increasing because of large community outbreaks in unimmunized individuals. Classic symptoms include fever, malaise, dark urine, and jaundice and are more common in older children and adults. People are most infectious 14 days before and seven days after the development of jaundice. Diagnosis of acute infection requires the use of serologic testing for immunoglobulin M anti-hepatitis A antibodies. The disease is usually self-limited, supportive care is often sufficient for treatment, and chronic infection or chronic liver disease does not occur. Routine hepatitis A immunization is recommended in children 12 to 23 months of age. Immunization is also recommended for individuals at high risk of contracting the infection, such as persons who use illegal drugs, those who travel to areas endemic for hepatitis A, incarcerated populations, and persons at high risk of complications from hepatitis A, such as those with chronic liver disease or HIV infection. The vaccine is usually recommended for pre- and postexposure prophylaxis, but immune globulin can be used in patients who are too young to be vaccinated or if the vaccine is contraindicated.

Hepatitis A.

Hepatitis A is a vaccine preventable liver infection caused by the hepatitis A virus. The occupational health nurse should be aware of the signs and symptoms of the virus, educate workers about the infection, and recommend immunization for workers traveling or working in high-risk areas for hepatitis A.

Foodborne transmission of hepatitis A and hepatitis E viruses: A literature review.

Foodborne viruses have been recognized as a growing concern to the food industry and a serious public health problem. Hepatitis A virus (HAV) is responsible for the majority of viral outbreaks of food origin worldwide, while hepatitis E virus (HEV) has also been gaining prominence as a foodborne viral agent in the last years, due to its zoonotic transmission through the consumption of uncooked or undercooked infected meat or derivatives. However, there is a lack of scientific reports that gather all the updated information about HAV and HEV as foodborne viruses. A search of all scientific articles about HAV and HEV in food until March 2020 was carried out, using the keywords "HAV", "HEV", "foodborne", "outbreak" and "detection in food". Foodborne outbreaks due to HAV have been reported since 1956, mainly in the USA, and in Europe in recent years, where the number of outbreaks has been increasing throughout time, and nowadays it has become the continent with the highest foodborne HAV outbreak report. Investigation and detection of HAV in food is more recent, and the first detections were performed in the 1990s decade, most of them carried out on seafood, first, and frozen food, later. On the other hand, HEV has been mainly looked for and detected in food derived from reservoir animals, such as meat, sausages and pate of pigs and wild boars. For this virus, only isolated cases and small outbreaks of foodborne transmission have been recorded, most of them in industrialized countries, due to HEV genotype 3 or 4. Virus detection in food matrices requires special processing of the food matrix, followed by RNA detection by molecular techniques. For HAV, a real-time PCR has been agreed as the standard method for virus detection in food; in the case of HEV, a consensus assay for its detection in food has not been reached yet. Our investigation shows that there is still little data about HAV and HEV prevalence and frequency of contamination in food, prevalent viral strains, and sources of contamination, mainly in developing countries, where there is no research and legislation in this regard. Studies on these issues are needed to get a better understanding of foodborne viruses, their maintenance and their potential to cause diseases.

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.

Factors Associated With Hepatitis A Mortality During Person-to-Person Outbreaks: A Matched Case-Control Study-United States, 2016-2019.

BACKGROUND AND AIMS: During 2016-2020, the United States experienced person-to-person hepatitis A outbreaks that are unprecedented in the vaccine era, during which case-fatality ratios reported by some jurisdictions exceeded those historically associated with hepatitis A. APPROACH AND RESULTS: To identify factors associated with hepatitis A-related mortality, we performed a matched case-control study (matched on age [±5 years] and county of residence in a 1:4 ratio) using data collected from health department and hospital medical records of outbreak-associated patients in Kentucky, Michigan, and West Virginia. Controls were hepatitis A outbreak-associated patients who did not die. There were 110 cases (mean age 53.6 years) and 414 matched controls (mean age 51.9 years); most cases (68.2%) and controls (63.8%) were male. Significantly (P < 0.05) higher odds of mortality were associated with preexisting nonviral liver disease (adjusted odds ratio [aOR], 5.2), history of hepatitis B (aOR, 2.4), diabetes (aOR, 2.2), and cardiovascular disease (aOR, 2.2), as well as initial Model for End-Stage Liver Disease (MELD) score ≥ 30 (aOR, 10.0), aspartate aminotransferase (AST)/alanine aminotransferase (ALT) ratio > 2 (aOR, 10.3), and platelet count < 150,000/µL (aOR, 3.7) among hepatitis A outbreak-associated patients in the independent multivariable conditional logistic regression analyses (each model adjusted for sex). CONCLUSIONS: Preexisting liver disease, diabetes, cardiovascular disease, and initial MELD score ≥ 30, AST/ALT ratio ≥ 1, and platelet count < 150,000/µL among hepatitis A patients were independently associated with higher odds of mortality. Providers should be vigilant for such features and have a low threshold to escalate care and consider consultation for liver transplantation. Our findings support the recommendation of the Advisory Committee on Immunization Practices to vaccinate persons with chronic liver disease, though future recommendations to include adults with diabetes and cardiovascular disease should be considered.

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.

Hepatitis a virus infection in Central-West Tunisia: an age structured model of transmission and vaccination impact.

BACKGROUND: The epidemiological pattern of hepatitis A infection has shown dynamic changes in many parts of the world due to improved socio-economic conditions and the accumulation of seronegative subjects, which leads to possible outbreaks and increased morbidity rate. In Tunisia, the epidemiological status of hepatits A virus is currently unknown. However, over the past years higher numbers of symptomatic hepatitis A virus infection in school attendants and several outbreaks were reported to the Ministry of Health, especially from regions with the lowest socio-economic levels in the country. The aim of this study was to investigate the current seroprevalence of hepatitis A virus antibodies in central-west Tunisia and assess the impact of hepatitis A virus vaccination on hepatitis A epidemiology. METHODS: Serum samples from 1379 individuals, aged 5-75 years, were screened for hepatitis A virus antibodies. Adjusted seroprevalence, incidence and force of infection parameters were estimated by a linear age structured SEIR (Susceptible-Exposed-Infectious-Recovered) compartmental model. A vaccine model was then constructed to assess the impact on hepatitis A virus epidemiology of 3 scenarios of vaccination strategies: one dose at 12-months of age, one dose at 6-years and one dose at 12-months and another at 6-years of age during 6 years. RESULTS: A rapid increase in anti-hepatitis A virus seroprevalence was noted during infancy and adolescence: 47% of subjects under 10-years-old are infected; the prevalence increases to 77% at 15-years and reaches 97% in subjects aged 30-years. The force of infection is highest between 10 and 30-years of age and the incidence declines with increasing age. The vaccine model showed that the 3-scenarios lead to a significant reduction of the fraction of susceptibles. The two doses scenario gives the best results. Single-dose vaccination at 6-years of age provides more rapid decrease of disease burden in school-aged children, as compared to single-dose vaccination at 12-months, but keeps with a non-negligible fraction of susceptibles among children < 6-years. CONCLUSIONS: Our study confirms the epidemiological switch from high to intermediate endemicity of hepatitis A virus in Tunisia and provides models that may help undertake best decisions in terms of vaccinations strategies.

Hepatitis A infections from food.

Food contaminated by hepatitis A virus (HAV) is responsible of the 2-7% of all HAV outbreaks worldwide. This review provides a description of the HAV characteristics, its infectivity and epidemiological features. In addition, this review compiles existing original papers reporting HAV prevalence, viral titres in foodstuffs and the risk associated with food contamination. The purpose of this revision is to conduct a structured and systematic review of the published molecular procedures for HAV detection in food, including the assessment of its infectivity.

Immunization Against Hepatitis A in Migrant Children: Three Vaccination Strategies, A Retrospective Study.

BACKGROUND: Hepatitis A is endemic in many countries. Swiss guidelines recommend vaccinating patients native from endemic areas. In Geneva's Children's hospital, migrant children are screened and vaccinated if seronegative. Because hepatitis A's prevalence is decreasing worldwide, more children are seronegative at arrival, highlighting the need for immunization in medical centers and refugee camps and questioning the benefits of systematic serology. Other Swiss hospitals vaccinate regardless of serostatus. This study's aim is to assess migrant children's immunity according to origin and age, and the cost-effectiveness of different immunization strategies. METHODS: We retrospectively analyzed 329 children's serostatus (1-16 years of age) between 2012 and 2015, using enzyme-linked fluorescent assay method. Serology and vaccine costs were based on local prices. Groups were compared with χ test and the age-seropositivity relationship was studied with linear regression. RESULTS: The predominant regions were the Eastern Mediterranean and European Regions with mostly negative serologies (71% and 83%) and the African Region with mostly positive serologies (79%). Immunity varied depending on birth country. Regardless of region, seropositivity increased with age (P < 0.001). The most cost-effective vaccination strategy was an individualized approach based on age and origin, reducing costs by 2% compared with serology-guided immunization and by 17% compared with systematic vaccination. CONCLUSIONS: Many migrant children >5 years old are seronegative and at risk of clinical infection. They need to be immunized. New guidelines according to age and origin should be defined to reduce immunization costs. We recommend systematic vaccination for patients <5 years old or native from low endemicity areas (≤25.7% of seropositivity). For the others, we propose serology-based vaccination.

An outbreak of hepatitis A in Canada: The use of a control bank to conduct a case-control study.

An outbreak of 18 cases of hepatitis A virus infection across five Canadian provinces was investigated. Case onsets occurred between October 2017 and May 2018. A retrospective matched case-control study was conducted to identify the likely source of the outbreak. Three matched controls were recruited for each case using a previously established control bank, supplemented by landline and cell phone call lists. Univariate and multivariate matched analyses were conducted to identify a potential outbreak source. Seventy-two per cent of controls were recruited through the control bank, and required on average 25.5 calls per recruited control; 20% of controls were recruited through a landline sample and 8% of controls were recruited through a cell phone sample, requiring an average of 847.3 and 331.7 calls per recruited control, respectively. Results of the analysis pointed to shrimp/prawns (odds ratio (OR) 15.75, p = 0.01) and blackberries (OR 7.21, p = 0.02) as foods of interest, however, an outbreak source could not be confirmed. The control bank proved to be a more efficient method for control recruitment than random call lists. Expanding the control bank size and using alternative methods, such as online surveys, may prove beneficial for increasing the timeliness of a case-control study during an outbreak investigation.

Brote de hepatitis A asociado a un manipulador de alimentos en Bizkaia, 2017 / Hepatitis A outbreak associated with a food handler in Bizkaia, 2017

INTRODUCCIÓN: La notificación de un caso de hepatitis A en un manipulador de alimentos de una pastelería y de 5 casos en trabajadores de una empresa tras consumir productos de la misma dio lugar a una investigación de brote. MÉTODOS: Se definieron como casos las personas con infección por el virus de la hepatitis A (VHA) confirmada por el laboratorio, con comienzo de síntomas en junio y que, durante el periodo de incubación, trabajaron con el manipulador y/o tuvieron contacto estrecho con él y/o consumieron productos de la pastelería. Se realizó una encuesta epidemiológica y se tomaron muestras de sangre para analizar la presencia de anticuerpos anti-hepatitis A. Se realizó la caracterización molecular por PCR, secuenciación de la región VP1/2A y análisis filogenético con el método de máxima verosimilitud, bootstrap 1000 (software MEGA 7.0). RESULTADOS: Se identificaron 14 casos primarios: 11 relacionados con el consumo de productos de la pastelería, 2 compañeros de trabajo del manipulador y un contacto familiar. Los 12 virus secuenciados eran genotipo IA, coincidiendo con una de las cepas (RIVM-HAV16-090) responsable de los brotes producidos en ese momento en Europa y que afectaban fundamentalmente a hombres que tienen sexo con hombres. CONCLUSIONES: Se debería reforzar la vacunación frente al VHA de grupos de riesgo para prevenir brotes futuros. La implementación del uso del tipado molecular en casos de hepatitis A podría mejorar la investigación de brotes, que se puede esperar que aumenten en el futuro debido al descenso de inmunidad en la población

INTRODUCTION: The reporting of one case of hepatitis A in a food handler at a bakery and five cases in employees of a company after consuming products from the same bakery prompted an outbreak investigation. METHODS: Outbreak cases were defined as individuals with laboratory-confirmed hepatitis A (HAV) infection, with symptoms which started in June and who, during the incubation period, worked with the food handler and/or had close contact with him and/or consumed products from the bakery. Epidemiologic questionnaires were performed and blood samples were obtained to be tested for the presence of anti-hepatitis A antibodies. Molecular characterisation was carried out by PCR, sequencing of the VP1/2A region and phylogenetic analysis with the maximum likelihood estimation method, bootstrap 1000 (MEGA 7.0 software). RESULTS: A total of 14 primary hepatitis A cases were identified: eleven cases related to the consumption of products from the bakery, two cases among co-workers of the food handler, and one case was a household contact. All 12 sequenced viruses were genotype IA, matching one of the strains (RIVM-HAV16-090) responsible for the outbreaks occurring at that time in Europe, mostly affecting men who have sex with men. CONCLUSIONS: HAV vaccination of at-risk groups should be reinforced in order to prevent future outbreaks. Increasing the use of molecular typing in hepatitis A cases could improve the investigation of outbreaks, which can be expected to increase in the future because of decreasing immunity in the population

Outbreaks of Hepatitis A in US Communities, 2017-2018: Firsthand Experiences and Operational Lessons From Public Health Responses.

Objectives. To identify and analyze common challenges from multiple US communities affected by the hepatitis A epidemic beginning in March 2017, and to identify operational lessons to support preparedness for similar future public health emergencies.Methods. We conducted semistructured interviews with health officials from 9 city or county health departments to collect the firsthand experience of public health responders. We collected data from January to October 2018 via teleconference. Key informants, whom we purposefully sampled, were senior public health officials who were directly involved in outbreak response or in preparing for potential hepatitis A outbreaks in their communities.Results. Several themes emerged during these discussions, including common challenges and solutions pertaining to sanitation and hygiene infrastructure, hepatitis A vaccination, health workforce availability and surge capacity, communication and stigma, and partnerships and coordination with local law enforcement and other stakeholders.Conclusions. By generating key, evidence-based operational lessons, this study can inform response activities in localities currently experiencing outbreaks as well as community preparedness for possible future outbreaks due to the presence of similar at-risk populations.

Suspected spread of hepatitis A virus from a restaurant among adults in rural area of the Kerala state, India.

India is experiencing a substantial decrease in early childhood exposure to hepatitis A virus (HAV). Kerala has experienced several hepatitis A outbreaks in young adults/adults in the recent past. The current hepatitis outbreak occurred in Nellikuzhi, Kerala state, India in December 2016. Investigation was carried by preparing a line list of suspected hepatitis cases. The blood and stool samples collected from patients were tested for anti-HAV/anti-Hepatitis E virus (HEV) immunoglobulin (IgM) antibodies and RNA respectively. A total of 562 suspected hepatitis cases were reported during the outbreak. Along with the first case (35 years, male), 86.1% (484/562) of the cases gave history of consuming food/water/cold drinks from one restaurant. Anti-HAV IgM positivity was 74.5% (73/98) in tested samples and amongst the positives, 81% were adults/young adults and adolescents. None of the samples tested positive for anti-HEV IgM. There were three HAV associated deaths without any co-morbidity. Sequence analysis of HAV RNA positive stool samples showed the presence of genotype IIIA HAV. The suspected source of the infection was a private well situated in the premise of a restaurant. Considering increasing HAV naive population in Kerala, there is a need to introduce hepatitis A vaccine in high-risk age groups.

Emerging hepatitis E virus compared with hepatitis A virus: A new sanitary challenge.

Hepatitis A (HAV) and E (HEV) viruses are able to cause liver disease in humans. Among the five classical hepatotropic viruses, they are mainly transmitted via the fecal-oral route. Historically, many similarities have thus been described between them according to their incidence and their pathogenicity, especially in countries with poor sanitary conditions. However, recent advances have provided new insights, and the gap is widening between them. Indeed, while HAV infection incidence tends to decrease in developed countries along with public health improvement, HEV is currently considered as an underdiagnosed emerging pathogen. HEV autochthonous infections are increasingly observed and are mainly associated with zoonotic transmissions. Extra hepatic signs resulting in neurological or renal impairments have also been reported for HEV, as well as a chronic carrier state in immunocompromised patients, arguing in favor of differential pathogenesis between those two viruses. Recent molecular tools have allowed studies of viral genome variability and investigation of links between viral plasticity and clinical evolution. The identification of key functional mutations in viral genomes may improve the knowledge of their clinical impact and is analyzed in depth in the present review.