Hepatitis A Virus Vaccine Inactivated and Liver disease

• Generic Name: hepatitis a adult vaccine
• Dosage Forms: n.a.
• Other Brand Names: Havrix, Vaqta

Prevention of HAV infection in adults, adolescents, and children ≥1 year of age.

Although HAV infection may be asymptomatic or relatively mild in many patients, it can result in substantial morbidity and associated health-care costs and work loss (11–22% of patients require hospitalization) and may be associated with fulminant hepatitis and hepatic failure. Overall HAV case-fatality rate in the US is 0.3–0.6%, but increases to about 2% in those ≥40 years of age. HAV is highly contagious (especially during the 2 weeks before onset of symptoms). The virus is transmitted person-to-person, principally through the fecal-oral route. HAV infection remains one of the most commonly reported vaccine-preventable diseases in travelers.

USPHS Advisory Committee on Immunization Practices (ACIP), AAP, and American Academy of Family Physicians (AAFP) recommend that all children be vaccinated against HAV infection at 1 year of age (i.e., 12 through 23 months of age), unless contraindicated.

ACIP, AAP, AAFP, American College of Obstetricians and Gynecologists (ACOG), and American College of Physicians (ACP) also recommend vaccination against HAV for all previously unvaccinated children, adolescents, and adults at high risk of exposure to HAV and for any other unvaccinated individual desiring protection from HAV infection.

For internationally adopted children whose immune status is uncertain, vaccinations can be repeated or serologic tests performed to confirm immunity. For HepA vaccine, ACIP states that the simplest approach is to revaccinate according to the US recommended immunization schedule if child is ≥12 months of age. Alternatively, test for serologic evidence of susceptibility to HAV. When a child is being adopted from a country with high or intermediate HAV endemicity, ACIP states that all previously unvaccinated individuals who anticipate close personal contact with the adoptee during the child’s initial 60 days in the US (e.g., household members, regular babysitters) should receive routine vaccination with HepA vaccine, with the first dose given as soon as adoption is planned (ideally ≥2 weeks before the child’s arrival). CDC website has information regarding which countries have high or intermediate levels of HAV endemicity.

HepA vaccine will not prevent hepatitis caused by other infectious agents (e.g., hepatitis B virus [HBV], hepatitis C virus [HCV], hepatitis E virus [HEV]).

When vaccination against both HAV and HBV infection is indicated in adults ≥18 years of age, the commercially available fixed-combination vaccine containing HepA vaccine and hepatitis B vaccine (HepA-HepB; Twinrix) can be used. ACIP, AAP, and AAFP state that use of a combination vaccine generally is preferred over separate injections of the equivalent component vaccines; considerations should include provider assessment (e.g., number of injections, vaccine availability, likelihood of improved coverage, likelihood of patient return, storage and cost considerations), patient preference, and potential for adverse effects. However, the HepA-HepB (Twinrix) fixed-combination vaccine should not be used for HAV postexposure prophylaxis.

Preexposure Vaccination Against HAV Infection in High-risk Groups

Preexposure vaccination in previously unvaccinated children, adolescents, or adults who are or will be at high risk of exposure to HAV or are at high risk of developing fulminant hepatitis and hepatic failure if they become infected with HAV.

ACIP, AAP, AAFP, and others recommend preexposure vaccination in previously unvaccinated children ≥12 months of age who reside in states, counties, or communities where the rate of HAV infection is high and in unvaccinated travelers, unvaccinated household or sexual contacts of an individual with confirmed HAV infection, and unvaccinated individuals at risk because of their occupation or high-risk behavior.

If HepA vaccine cannot be used because it is contraindicated or unavailable and short-term protection against HAV is needed, preexposure passive immunization with IGIM is recommended.

In states, counties, or communities where the rate of HAV infection is high, ACIP recommends that existing selective preexposure HepA vaccination programs for children 2 through 18 years of age be maintained. In such areas, new efforts focused on routine vaccination of all children at 1 year of age should enhance, not replace, ongoing programs directed at a broader population of children. In areas without existing selective vaccination programs, catch-up vaccination of unvaccinated children 2 through 18 years of age may be considered. Such catch-up vaccination programs may be especially warranted because of rising incidence or ongoing outbreaks of HAV among children or adolescents.

HIV-infected individuals, especially those with chronic liver disease (including those coinfected with HBV or HCV), should be vaccinated against HAV. ACIP, AAP, CDC, National Institutes of Health (NIH), Infectious Diseases Society of America (IDSA), Pediatric Infectious Diseases Society, and others recommend that HAV-susceptible, HIV-infected adults, adolescents, and children receive HepA vaccine. Consider that the vaccine may be less immunogenic in immunocompromised individuals.

Travelers to areas with intermediate to high levels of endemic HAV are at risk of exposure to the disease, and ACIP, CDC, WHO, and others recommend preexposure vaccination against HAV for such individuals. CDC states vaccination against HAV can be considered in individuals traveling to any destination. CDC website has information regarding which countries have high or intermediate levels of HAV endemicity. Risk of acquiring HAV while traveling varies with living conditions, length of stay, and incidence of HAV infection in the area visited. Consider that many cases of HAV occur in travelers to developing countries with standard tourist itineraries, accommodations, and food consumption behaviors. Ideally, the first dose of HepA vaccine should be administered as soon as travel to countries with high or intermediate HAV endemicity is considered.

Alternatively, if the vaccine is contraindicated or cannot be used, passive immunization with a single dose of IGIM may provide protection for up to 3 months. For optimal protection in travelers at greatest risk for HAV (older adults or individuals with altered immunocompetence, chronic liver disease, or other chronic medical condition) who plan to depart in <2 weeks, a dose of IGIM should be given concomitantly with the initial dose of HepA vaccine (at a different site). ACIP states that the fixed-combination vaccine containing HepA vaccine and HepB vaccine (HepA-HepB; Twinrix) should not be used for preexposure vaccination in travelers who will depart within 2 weeks.

Household and sexual contacts of individuals with confirmed HAV infection are at increased risk of exposure to HAV. Sexually active male adolescents and adults who have sex with men (homosexual, bisexual) should be vaccinated against HAV. Primary-care clinicians and those in specialty medical settings should offer the vaccine to such individuals; strategies to increase coverage (e.g., use of standing orders) should be considered.

Individuals who illicitly use injectable or noninjectable drugs may be at increased risk of exposure to HAV infection and should be vaccinated against HAV. Clinicians should obtain a complete history to identify individuals who might benefit from HepA vaccination (e.g., those who use illicit drugs or who are at increased risk for such drug use). Clinicians should consider implementing strategies to increase vaccine coverage in these patients (e.g., use of standing orders).

Individuals with hemophilia or other congenital bleeding disorders who are HAV-seronegative should be vaccinated against HAV. Improved donor screening, more effective viral-inactivation procedures, and/or purification or filtration procedures have reduced, but not completely eliminated, the risk of pathogen transmission from plasma-derived clotting factors. Therefore, recipients of blood products (e.g., whole blood, packed RBCs, plasma) and plasma-derived preparations (e.g., albumin human, antihemophilic factor [human], anti-inhibitor coagulant complex, factor IX [human], factor IX complex) may be at increased risk of HAV infection.

Workers handling HAV-infected nonhuman primates and workers in contact with live HAV in a research laboratory setting should be vaccinated against HAV. Routine vaccination against HAV is not currently recommended for other occupational groups in the US.

Individuals with chronic liver disease and those who are awaiting or have undergone liver transplantation should be vaccinated against HAV. Although individuals with chronic liver disease are not at increased risk of acquiring HAV infection, such individuals are at increased risk of severe consequences of HAV infection, including fatal fulminant hepatitis and hepatic failure.

Some clinicians recommend that individuals with HBV or HCV infection, autoimmune hepatitis, or primary biliary cirrhosis be vaccinated against HAV. ACIP states that current data do not support routine vaccination of individuals who have chronic HBV or HCV infection but do not have evidence of chronic liver disease.

Food handlers and restaurant employees may be vaccinated against HAV. Vaccination may be considered in restaurant employees in areas where state and local health authorities or private employers have determined that such vaccination is indicated to decrease the frequency of HAV evaluations of food handlers and decrease the need for HAV postexposure prophylaxis in restaurant patrons. Under these circumstances, a record of HepA vaccination should be provided to vaccinated food handlers, those not vaccinated should be informed of the signs and symptoms of HAV infection, and all food handlers should be instructed on food preparation practices that reduce risk of fecal contamination. Routine use of HepA vaccine in all food handlers is not economically feasible from a societal or food industry perspective. Occasionally, vaccination of food handlers may be considered during a community outbreak.

Incarcerated adolescents in correctional facilities located in states with existing HepA vaccination programs for adolescents should receive HepA vaccine. Because of the likelihood that adolescents in juvenile correctional systems have indications for the vaccine, other correctional facilities also should consider routine HepA vaccination of all adolescents under their care. Test those with signs or symptoms of hepatitis for acute HAV, HBV, and HCV infection. Report those with HAV to the local health department and give appropriate postexposure prophylaxis with HepA vaccine to susceptible exposed residents.

If a community-wide outbreak of HAV occurs, accelerated HepA vaccination programs should be considered. A decision to initiate an outbreak-control vaccination program should take into account the feasibility of rapidly vaccinating the target population of children, adolescents, or young adults, and the costs associated with such a program. Routine vaccination of children in affected communities should continue in order to maintain high levels of immunity and prevent future epidemics.

HAV outbreaks in child-care centers have decreased considerably since the implementation of routine childhood immunization against HAV and further decreases are expected. ACIP does not recommend routine preexposure vaccination with HepA vaccine for personnel in child-care centers. However, HAV postexposure prophylaxis may be indicated if HAV is reported in attendees or staff.

ACIP does not recommend routine preexposure vaccination with HepA vaccine in hospitals or schools and institutions for the developmentally disabled because the frequency of outbreaks in these institutions is not high enough to warrant such recommendations. Outbreaks involving student-to-student transmission in primary and secondary schools are rare in developed countries, but outbreaks have been documented; in developing countries, outbreaks among children in primary schools are more common. If an epidemiologic investigation indicates HAV transmission has occurred among students in a school or among patients or between patients and staff in a hospital, HAV postexposure prophylaxis should be administered to individuals who have close contact with index patients.

ACIP and Hospital Infection Control Practices Advisory Committee (HICPAC) state that routine preexposure vaccination with HepA vaccine or routine use of HAV postexposure prophylaxis in health-care personnel providing care to patients with HAV infection is not indicated. Instead, hygienic practices should be emphasized and health-care personnel should be made aware of the risk of exposure to HAV and precautions regarding direct contact with potentially infective materials. In documented outbreaks of HAV infection, HAV postexposure prophylaxis may be indicated in health-care workers and others who have close contact with the infected individuals. The usefulness of HepA vaccine in controlling outbreaks in health-care settings has not been investigated.

Postexposure Prophylaxis of HAV Infection

Postexposure prophylaxis of HAV in susceptible individuals with recent (within 2 weeks) exposure to HAV.

The choice of active immunization with HepA vaccine and/or passive immunization with IGIM for postexposure prophylaxis should take into account the magnitude of risk associated with the exposure and characteristics of the patient that may be associated with more severe manifestations of HAV (e.g., older age, chronic liver disease).

Although IGIM was traditionally the recommended regimen for HAV postexposure prophylaxis since it is 80–90% effective if administered within 2 weeks of exposure, there is some evidence that monovalent HepA vaccine administered within 2 weeks of exposure may be as effective as IGIM in healthy individuals 1–40 years of age. The vaccine also offers certain advantages over IGIM (e.g., induces active immunity and longer protection, more readily available, easier to administer, greater patient acceptance).

For HAV postexposure prophylaxis in healthy individuals 12 months to 40 years of age, ACIP prefers use of monovalent HepA vaccine. In adults >40 years of age, ACIP prefers use of IGIM since data not available to date regarding efficacy of the vaccine for postexposure prophylaxis in this age group and these individuals are at risk of more severe manifestations of HAV; the vaccine can be used if IGIM cannot be obtained. IGIM should be used for HAV postexposure prophylaxis in children <12 months of age, immunocompromised individuals, individuals with chronic liver disease, and whenever the vaccine is contraindicated.

In those individuals in whom IGIM is preferred for HAV postexposure prophylaxis, a dose of HepA vaccine should be given simultaneously (using different syringes and different injection sites) if the vaccine is indicated for other reasons (e.g., catch-up vaccination, preexposure vaccination in high-risk groups) and is not contraindicated. If a dose of HepA vaccine is used with or without IGIM for HAV postexposure prophylaxis, a second (booster) dose of the vaccine should be administered according to the usually recommended schedule to ensure long-term protection.

Monovalent HepA vaccine (Havrix, Vaqta) should be used when active immunization is indicated for HAV postexposure prophylaxis. Data not available to date regarding efficacy of the fixed-combination vaccine containing HepA vaccine and HepB vaccine (HepA-HepB; Twinrix) for postexposure prophylaxis.

If HAV postexposure prophylaxis is indicated, administer as soon as possible (within 2 weeks of exposure). Data not available regarding efficacy of HAV postexposure prophylaxis administered >2 weeks after exposure.

HAV postexposure prophylaxis is indicated in all previously unvaccinated individuals who have had household or sexual contact (within the last 2 weeks) with an individual with serologically confirmed HAV. Also consider HAV postexposure prophylaxis for individuals exposed (within the last 2 weeks) through other types of ongoing, close personal contact (e.g., regular babysitting).

Contacts who have shared illicit drugs (within the last 2 weeks) with an individual with serologically confirmed HAV should receive HAV postexposure prophylaxis.

Administer HAV postexposure prophylaxis to all previously unvaccinated staff and attendees of child-care centers or homes if ≥1 case of HAV is recognized in children or employees or if HAV is recognized in ≥2 households of center attendees (within the last 2 weeks). In centers that do not provide care to children who wear diapers, HAV postexposure prophylaxis is indicated only in classroom contacts of the index patient. If an outbreak occurs (i.e., HAV in ≥3 families), HAV postexposure prophylaxis should also be considered for members of households that have diapered children attending the center.

If HAV is diagnosed in a food handler, ACIP recommends HAV postexposure prophylaxis (within 2 weeks) for other food handlers at the same establishment. Because common-source transmission to patrons is unlikely, HAV postexposure prophylaxis is not usually indicated for restaurant patrons, but may be considered if the food handler directly handled uncooked or cooked food and had diarrhea or poor hygienic practices and if patrons can be identified and treated within 2 weeks of exposure. Settings where repeated HAV exposure might have occurred (e.g., institutional cafeterias) warrant stronger consideration of postexposure prophylaxis for patrons.

When an individual with HAV is admitted to a hospital, health-care personnel do not need to receive routine HAV postexposure prophylaxis; careful hygienic practices should be emphasized in such situations.

If an epidemiologic investigation indicates that HAV transmission has occurred among students in a school or among hospital patients and/or hospital staff, ACIP recommends HAV postexposure prophylaxis in individuals who have close contact with index patients.

Routine HAV postexposure prophylaxis is not indicated when a single HAV case occurs in an elementary or secondary school or an office or other work setting and the source case is outside the school or work setting.

HAV postexposure prophylaxis is not usually indicated after a common-source HAV outbreak if cases have begun to occur because the 2-week period when such prophylaxis is known to be effective will have been exceeded.