Serologic studies of transmission of hepatitis A in humans

The History of Hepatitis A

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Prevention of Hepatitis A Virus Infection in the United States: Recommendations of the Advisory Committee on Immunization Practices, 2020

HEPATITIS A IS A VACCINE-PREVENTABLE, COMMUNICABLE DISEASE OF THE LIVER CAUSED BY THE HEPATITIS A VIRUS (HAV). THE INFECTION IS TRANSMITTED VIA THE FECAL-ORAL ROUTE, USUALLY FROM DIRECT PERSON-TO-PERSON CONTACT OR CONSUMPTION OF CONTAMINATED FOOD OR WATER. HEPATITIS A IS AN ACUTE, SELF-LIMITED DISEASE THAT DOES NOT RESULT IN CHRONIC INFECTION. HAV ANTIBODIES (IMMUNOGLOBULIN G [IGG] ANTI-HAV) PRODUCED IN RESPONSE TO HAV INFECTION PERSIST FOR LIFE AND PROTECT AGAINST REINFECTION; IGG ANTI-HAV PRODUCED AFTER VACCINATION CONFER LONG-TERM IMMUNITY. THIS REPORT SUPPLANTS AND SUMMARIZES PREVIOUSLY PUBLISHED RECOMMENDATIONS FROM THE ADVISORY COMMITTEE ON IMMUNIZATION PRACTICES (ACIP) REGARDING THE PREVENTION OF HAV INFECTION IN THE UNITED STATES. ACIP RECOMMENDS ROUTINE VACCINATION OF CHILDREN AGED 12-23 MONTHS AND CATCH-UP VACCINATION FOR CHILDREN AND ADOLESCENTS AGED 2-18 YEARS WHO HAVE NOT PREVIOUSLY RECEIVED HEPATITIS A (HEPA) VACCINE AT ANY AGE. ACIP RECOMMENDS HEPA VACCINATION FOR ADULTS AT RISK FOR HAV INFECTION OR SEVERE DISEASE FROM HAV INFECTION AND FOR ADULTS REQUESTING PROTECTION AGAINST HAV WITHOUT ACKNOWLEDGMENT OF A RISK FACTOR. THESE RECOMMENDATIONS ALSO PROVIDE GUIDANCE FOR VACCINATION BEFORE TRAVEL, FOR POSTEXPOSURE PROPHYLAXIS, IN SETTINGS PROVIDING SERVICES TO ADULTS, AND DURING OUTBREAKS.

Seroepidemiology of Helicobacter pylori and hepatitis A virus and the mode of transmission of infection: a 9-year cohort study in rural Japan

We compared the seroepidemiologic patterns of Helicobacter pylori and hepatitis A virus (HAV) infections among participants in 2 independent cross-sectional studies conducted in Japan in 1986 and 1994. Subgroups were monitored with successive blood sampling. H. pylori and HAV infection status was defined by results of enzyme-linked immunosorbent assay. In 1986, the prevalence of H. pylori infection and HAV infection, respectively, were 80% and 70% among adults and 31% and 5% among children. The prevalence of both infections increased with age. Concordant infections were found in 74.5% of adults (kappa=0.2) versus 2% of children (kappa=0.05). During the 9-year study period, the incidence of H. pylori infection was 1.1% among adults and 2% among children. The seroprevalence of HAV remained constant. The disparity between the increase in prevalence of H. pylori and HAV infection with age is likely associated with improvements in hygienic practices. The discordance between the presence of the infections among younger persons is evidence against a common source and/or vehicle for transmission.

Sensitive assays for hepatitis A antibodies

Two commercial assay kits for detecting antibody to hepatitis A virus (anti-HAV) have been modified in order to increase their sensitivity. These modifications are made by less dilution of the test serum, in the case of Abbott HAVAB-M assay, or by an increase in the volumetric ratio of the test serum to the labeled anti-HAV in the case of the Abbott HAVAB assay. These modifications result in 5- to 20-fold increases in test sensitivity and enable the detection of anti-HAV at 2-3 weeks following vaccination. The earlier detection of anti-HAV is important to vaccine development in assuring the presence of antibody levels in travelers sooner after vaccination.

Immunologic approaches to assessing the response to inactivated hepatitis A vaccine

Natural immunity to hepatitis A virus (HAV) is complex and likely to involve several distinct arms of the immune system. There is evidence that natural killer cells, human leukocyte antigen (HLA)-restricted cytotoxic T cells, and antibody-secreting cells of B-cell lineage all play roles in the immune response to infection with HAV. However, antibody alone is sufficient to provide a high level of protection against clinical disease. A comparison of the serum levels of antibody to HAV (anti-HAV) following administration of immune serum globulin and hepatitis A vaccine may provide a useful estimate of vaccine efficacy. Such comparisons may be accomplished using solid-phase immunoassays for detection of anti-HAV. However, tests which measure antibody capable of neutralizing virus in vitro are generally more sensitive than solid-phase immunoassays. The use of endogenously labelled virus in radioimmunoprecipitation assays shows promise of providing an equally sensitive means of measuring antibodies which are reactive with HAV particles.

The seroepidemiology of hepatitis A and B in a Japanese town

Sera collected from 1,118 healthy children and adults aged between four years and 90 years during the period 1989 to 1990, were tested for serological markers of hepatitis A virus (HAV) [antibody to HAV (anti-HAV)] and hepatitis B virus (HBV) [hepatitis B surface antigen (HBsAg) and antibody to hepatitis B surface antigen (anti-HBsAb)]. The overall prevalence rates of anti-HAV, HBsAg, and anti-HBV were 20.2%, 0.36%, and 5.1%, respectively. No body was found to be positive for anti-HAV below 30 years of age but more than 70% of the adults aged 50 years or over were positive for anti-HAV. The level of exposure of HAV infection is declining in Japan and paradoxically at the same time a vast majority of people are becoming susceptible to more severe illness. The fall in prevalence of HBsAg possibly represents the positive impact of ongoing vaccination programs and other preventive measures against HBV.

Differential diagnosis of acute viral hepatitis using rapid, fully automated immunoassays

We report the development of three rapid, fully automated immunoassays allowing the differential diagnosis of acute viral hepatitis. These assays detect HBsAg, IgM antibody to hepatitis B core antigen (IgM anti-HBc) and IgM antibody to hepatitis A virus (IgM anti-HAV) using the IMx instrument system. All IMx assays were run in less than 45 minutes and all steps were fully automated including specimen dilution steps. Specimens from blood donors, diagnostic and hospital patients, and individuals with a variety of infectious and immune diseases were tested for IgM anti-HAV (n = 1473) or for IgM anti-HBc (n = 1606) or for HBsAg (n = 9700) by the IMx and commercially available EIA and RIA. Each IMx assay showed 99.8% agreement with current EIA. Reproducibility in all hepatitis IMx assays was significantly better than that observed with manual or semiautomated assays; within-run and between-run % CV ranged from 2.2 to 4.8 and 3.5 to 10.3 respectively. In 29 acute hepatitis B patients studied, HBsAg and IgM anti-HBc were detected in the first available patient bleed collected from 0 to 4 week from the onset of symptoms. IgM anti-HBc persisted at reactive levels in the IMx assay for 1 to 24 weeks (mean 12.1 +/- 5.3 weeks) after the patient presented with symptoms. In individuals exposed to hepatitis A, IgM anti-HAV was detectable by IMx by 40 days post exposure (average 33.5 days) and IgM had declined to unreactive levels in IMx for all patients by from 3 to 6 months post exposure. These data demonstrate the use of these rapid IMx assays for differentiation of acute hepatitis A and B.

Hepatitis A, B, C, D and E viruses: structure of their genomes and general properties

Hepatitis A virus is an enteric picornavirus. Its genome is a single stranded RNA molecule of positive-strand polarity of 7478 bases. This sequence codes for a polyprotein which is processed to give rise to viral proteins VP-1, VP-2, VP-3 and others. Hepatitis B virus, a major worldwide infectious and cancer promoting agent contains a DNA genome of 3226 base pairs that replicates by a reverse transcriptase via an RNA intermediate. Extensive sequencing and expression experiments have revealed four major genes named surface, core, polymerase and X which are coded in more than one reading frame. Furthermore, within a frame, proteins are expressed from multiple initiation codons resulting in several related products. The viral genome of hepatitis C virus (nonA-nonB), an elusive major infectious agent, has recently been cloned. This genome is a single positive-stranded RNA of at least 10,000 bases which codes for several antigens, some of them associated specifically with nonA-nonB hepatitis infections. The hepatitis D (delta) viral agent, an infectious agent requiring a hepadnarious for propagation, contains a covalently closed circular single-stranded RNA genome of 1167 nucleotides. This genome encodes the protein p24 and p27 that bind specifically to antisera from patients with chronic hepatitis D infections.

Management of pregnant women with contagious infections at delivery

Since 1970 pregnant women with contagious infections in the country of Stockholm have been delivered at the Danderyd Hospital, the only hospital in the area which has departments of obstetrics and pediatrics as well as infectious diseases. This paper presents data from a prospective study carried out during a period of 10 years (1975-1984). The study includes 303 women and their newborns who for various reasons were transferred to the Department of Infectious Diseases (DID) before or after delivery. A comprehensive microbiological investigation was made in order to establish an etiological diagnosis in all women included in the study. A possible transmission of the infection from the mother to her fetus/child before or after delivery was also investigated. Only 0.17% of the pregnant women in the area needed care at the DID at delivery or in the puerperal period. 9% of the deliveries occurred at another hospital, 32% at the DID and the remaining at the obstetrical department, Danderyd Hospital. The rate of complications, including cesarean sections, was 12%. Of the 165 women suffering from an infectious disease at the time of delivery, 40% had a verified viral disease--in most cases varicella or mumps, 28% had a bacterial infection and for 32% no etiology of the disease could be established. The study population also includes women suspected either to be incubated with a contagious disease or to be carriers of infectious agents, as well as healthy mothers whose newborns were expected to be carriers of infectious agents such as rubella and varicella. None of the women died during the study period but 5 were seriously ill and 3 needed intensive care. The rate of stillbirths was the same as reported among all births in the country of Stockholm but the perinatal mortality rate was significantly higher (see also a following article, ref. 27). Our routines prove the necessity to take special care of pregnant women carrying a contagious infectious agent at term.

Antibody to hepatitis A virus after overt and asymptomatic hepatitis A infection

The titres of antibody to hepatitis A virus (anti-HAV) were found to fall rapidly during 3-4 years after hepatitis A and more slowly thereafter, though they never reached undetectable levels in at least 23 years. The levels of anti-HAV in convalescents after overt hepatitis A were found to be significantly much higher than in those who had anti-HAV as a result of asymptomatic infection.

Hepatitis A virus replication in tamarins and host immune response in relation to pathogenesis of liver cell damage

Hepatitis A virus (HAV) shedding in the faeces, appearance of HAV-Ag (antigen) in the liver, and development of humoral immunity to HAV have been studied in experimentally infected tamarins. The appearance of liver damage measured by transaminase elevation and histology, in relation to the above variables, suggests that the virus is not cytopathic and the immune system contributes to the production of liver cell damage. Preliminary data suggest that HAV replication may occur in the mucosa of the small intestine and in the liver.

Virus-binding activity of fibronectin: masking of hepatitis A virus

Human plasma fibronectin interacts with viruses. When fibronectin-containing human sera negative for antibodies to hepatitis A virus (HAV) were added to suspensions of HAV, radioimmunological detection of HAV was reduced. This masking effect seemed to depend on the fibronectin concentration of the sera: plasma fibronectin purified by cryoprecipitation and affinity chromatography showed a masking effect on purified HAV which was dependent on the concentrations of fibronectin and HAV. Fibronectin peptides were obtained by subtilisin digestion: the non-collagen-binding regions of the fibronectin molecule were involved in the binding of HAV. We conclude that fibronectin has a virus-binding activity which interferes with radioimmunological methods for virus detection, and may contribute to the frequent transmission of hepatitis viruses by blood products enriched in fibronectin.

Hepatitis A virus immunoglobulin M antibody in acute neurological disease

Sera from 167 patients with Guillain-Barré syndrome, 224 patients with other neurological diseases, and 10 normal subjects were tested for hepatitis A virus-specific immunoglobulin M antibodies. Two patients with classic Guillain-Barré syndrome and 1 patient with acute myeloradiculopathy had high titers of virus-specific IgM antibody. All three patients had jaundice and laboratory evidence of liver involvement before the onset of the neurological disease. None of the other sera from patients with Guillain-Barré syndrome or control subjects were positive for hepatitis A virus.

Transmission of hepatitis A virus among recently captured Panamanian owl monkeys

The presence of antibody to hepatitis A virus (anti-HAV) in 60% of procured owl monkeys (Aotus trivirgatus) held within the United States prompted a study of recently captured A trivirgatus in Panama. Only 2 of 145 newly captured monkeys, but all of 35 A trivirgatus held within a colony for over 100 days, were found to have anti-HAV. Of 41 sero-negative, newly captured monkeys followed prospectively, 25 became infected with hepatitis A virus (HAV) as evidenced by seroconversion or demonstration of virus in the liver at death. Only one monkey that survived over 60 days within the colony was not infected. HAV was identified in the feces of most infected monkeys prior to the development of antibody and was antigenically indistinguishable from human HAV in cross-blocking radioimmunoassays. This colony-centered epizootic provides strong evidence that A trivirgatus is susceptible to HAV and should be investigated further as a potential model of human hepatitis A.

Hepatitis A virus: virologic, clinical, and epidemiologic studies

The last decade has borne witness to accelerated expansion of our understanding of hepatitis A virus. The agent of type A hepatitis is an RNA virus with a mean diameter of 27 nm. and biochemical-biophysical properties of an enterovirus. A variety of sensitive specific serologic techniques have been developed with which to identify hepatitis A virus and antibody, and both chimpanzees and marmosets have been studied extensively as experimental animal models. As a result of these studies, in vitro cultivation of hepatitis A virus has finally been accomplished, and a commercial radioimmunoassay for IgM antibody to hepatitis A virus has been developed for the rapid diagnosis of hepatitis A virus infection during acute illness. Clinically the illness caused by hepatitis A virus is relatively mild, often subclinical, and of limited duration and does not progress to chronic liver disease. This relative clinical benignity is reflected, according to preliminary histologic observations, in the sparing of the centrozonal area of the liver lobule. Rarely, however, hepatitis A virus can cause fulminant hepatitis. Type A hepatitis is transmitted almost exclusively by the fecal-oral route, and its spread is enhanced by epidemiologic settings favoring dissemination of enteric infections. Hepatitis A virus does not contribute to transfusion associated or other types of percutaneously transmitted hepatitis. Exposure to the virus increases as a function of age and decreasing socioeconomic class, but the incidence of hepatitis A virus infection in urbanized societies is decreasing. There is no evidence for the existence of chronic hepatitis A virus carriage; natural perpetuation of hepatitis A virus in urban communities appears to depend on a reservoir of nonepidemic, clinically inapparent cases. Until a vaccine, now being developed, becomes available, prevention of hepatitis A virus infection will continue to depend on maintenance of high standards of environmental and personal hygiene and on timely administration of immune serum globulin. Such prophylaxis may confer long lasting passive-active immunity but more frequently prevents infection entirely.

Acute hepatitis A infection in West Scotland

In 1979, 43 cases of acute hepatitis A infection were diagnosed by the presence of hepatitis A specific IgM antibodies in acute phase sera. The majority (34) were in patients under 30 years with 13 in children under 10 years: 23 were males. Few cases occurred in the winter months, most in autumn, with a peak in September. A total of 17 cases had a history of recent travel abroad, and six of contact with a case of jaundice/hepatitis. There were 11 cases in members of the immigrant community.

Disappearance of hepatitis B surface antigen during an unusual case of fulminant hepatitis B

A 30-year-old surgical resident was admitted to the hospital with symptoms of acute hepatitis; two days later he became comatose. Hepatitis B surface antigen had been detected in his serum two days prior to admission, but it was not detected at any time thereafter. Hepatitis B e antigen, antibody to hepatitis B core antigen, and antibody to hepatitis B surface antigen were detected using sensitive radioimmunoassays at admission. Titers of antibody to hepatitis B core antigen increased over the next five weeks. Clearance of hepatitis B e antigen and subsequent appearance of antibody to hepatitis B e antigen accompanied clinical improvement and recovery. This unusual case documents that hepatitis B surface antigen can become undetectable during the course of fulminant hepatitis B and indicates the importance of tests for other serologic markers of hepatitis B virus in the evaluation of hepatitis B surface antigen-negative fulminant hepatitis.

Epidemic and endemic hepatitis in India: evidence for a non-A, non-B hepatitis virus aetiology

69 serum pairs from two common-source water-borne outbreaks and one series of endemic cases of hepatitis in three parts of India were tested for hepatitis A and hepatitis B virus infections. None of the patients had evidence of HAV infection and only 10.1% had evidence of HBV infection. A large proportion of hepatitis in India seems to be caused by previously unrecognised agents.

Prevalence of antibody against hepatitis A in Sweden in relation to age and type of community

Sera collected in 1968 from persons selected on a statistical basis as being a representative sample of the Swedish population, were tested for antibody against hepatitis A (anti-HAV). The prevalence of anti-HAV increased with age from 4% (3/83) among 15-19 year olds (born between 1948 and 1952) to 87% (68/78) among 60-69 year olds (born between 1898 and 1907), and was furthermore higher in cities than in rural areas for corresponding age groups.

Non-a, non-b hepatitis: identification of hepatitis-B-like virus particles in serum and liver

Hepatitis B virus-like particles including: small spheres and filaments 15--25 nm in diameter together with a 35--40 nm Dane particle-like virion have been identified in sera of patients with non-A, non-B hepatitis. In a coded serological study, such particles were detected transiently in 3/4 acute, and persistently in 7/8 chronic cases of non-A, non-B hepatitis with non-A, non-B antigenemia. Only 2/12 similar cases without non-A, non-B antigens (Ag) in serum had detectable particles but neither patients with drugs, or type A hepatitis, nor cases of obstructive jaundice. The particles did not express hepatitis B surface (HBs) or non-A, non-B Ag at their surface but were associated, in three patients, with significant endogenous DNA polymerase activity. Furthermore, particles similar to hepatitis B cores (BHc) and also associated with DNA polymerase activity were demonstrated by sucrose gradient ultracentrifugation of a liver homogenate obtained from a patient who had died of non-A, non-B hepatitis. The non-A, non-B hepatitis virion described here appears, therefore, as a hepatitis B-like virus. The exact kinship between these two agents is currently being investigated.

Detection of virus-associated antigen in serum and liver of patients with non-A non-B hepatitis

In a search for serological markers of non-A non-B(NANB) hepatitis, sera from repeatedly transfused and convalescent patients were assayed by immunodiffusion against sera from 12 patients with early acute NANB hepatitis. A new antigen/antibody system distinct from HBsAg was demonstrated in 8 cases. To assess the specificity of the test, serial sera from 17 patients with acute hepatitis of known aetiology (10 due to hepatitis-B virus, 4 to hepatitis-A virus, 3 to drugs) were tested twice a month, together with sera from 14 NANB patients obtained during a prospective post-transfusion study. NANB antigen (Ag) was detected in at least one sample from 12 of the 14 NANB patients (86%) but in none of the other groups. NANB Ag appeared after or just before elevation of transaminase levels and was cleared before they fell to normal. 4 of 5 patients who showed seroconversion to NANB antibody (Ab) had transient hepatitis. In contrast, the alanine adminotransferase value returned to normal in only 1 of the 5 with persistent NANB antigenaemia during 6 months' follow-up. NANB Ag was also demonstrated by immunodiffusion in liver extracts from patients with chronic NANB hepatitis with antigenaemia. Fluorescein-isothiocyanate-labelled gammaglobulins with strong NANB Ab activity revealed specific nuclear fluorescence in foci of hepatocytes on cryostat sectons of these livers but in none of 6 control human livers. The results suggest that the antigen and antibody are specifically linked to NANB hepatitis of long incubation period.

Immunoglobulin prophylaxis against hepatitis A among Swedish UN soldiers in an endemic region

Six hundred and fifteen Swedish soldiers (X = 24.9 years) serving with the UN forces in Cyprus were tested for antibody against hepatitis A (anti-HAV) before and after six months' service. Before the service, a high susceptibility to hepatitis A was found, as only 2.3% (14/615) had anti-HAV. In comparison, the prevalence of anti-HAV among 124 native Cypriots (X = 23.9 years) was 97% (120/124), which showed Cyprus to be a region where hepatitis A is endemic. The soliders were given immunoglobulin (IG) prophylaxis (2 ml of 16.5% IG) against hepatitis A very third month. The incidence of subclinical seroconversion against hepatitis A among the Swedish soliders was 0.2% (1/615). It was concluded that the IG-prophylaxis scheme used seems to be highly effective and probably completely prevents even subclinical seroconversion against hepatitis A in non-immune persons in regions where hepatitis A is endemic.