Preexposure Protection Against Hepatitis A Virus (HAV) Infection
The following recommendations for hepatitis A vaccination are intended to further reduce hepatitis A morbidity and mortality in the United States and make possible consideration of eventual elimination of HAV transmission. Hepatitis A vaccination is recommended routinely for children, for persons who are at increased risk for infection, and for any person wishing to obtain immunity.
Children
- All children should receive hepatitis A vaccine at age 1 year (i.e., 12 to 23 months). Vaccination should be completed according to the licensed schedules (see Tables 2 and 3 in the original guideline document) and integrated into the routine childhood vaccination schedule. Children who are not vaccinated by age 2 years can be vaccinated at subsequent visits.
- States, counties, and communities with existing hepatitis A vaccination programs for children aged 2 to 18 years are encouraged to maintain these programs. In these areas, new efforts focused on routine vaccination of children aged 1 year should enhance, not replace, ongoing programs directed at a broader population of children.
- In areas without existing hepatitis A vaccination programs, catch-up vaccination of unvaccinated children aged 2 to 18 years can be considered. Such programs might especially be warranted in the context of increasing incidence or ongoing outbreaks among children or adolescents.
Persons At Increased Risk for HAV Infection
Persons Traveling to or Working in Countries That Have High or Intermediate Endemicity of Infection
All susceptible persons traveling to or working in countries that have high or intermediate hepatitis A endemicity (see Figure 4 in the original guideline document) should be vaccinated or receive immune globulin (IG) before departure (see Tables 1 to 4 in the original guideline document). Hepatitis A vaccination at the age-appropriate dose is preferred (see (Tables 2 to 4 in the original guideline document). Prevaccination testing should be considered for older travelers or for younger persons in certain population groups (see "Prevaccination Serologic Testing for Susceptibility" in the original guideline document).
Travelers to Australia, Canada, western Europe, Japan, or New Zealand (i.e., countries in which endemicity is low) are at no greater risk for infection than persons in the United States. Data are not available regarding the risk for hepatitis A for persons traveling to certain areas of the Caribbean, although vaccine or IG should be considered if travel to areas that have questionable sanitation is anticipated.
The first dose of hepatitis A vaccine should be administered as soon as travel is considered. Travelers who are administered vaccine can be assumed to be protected within 4 weeks after receiving the first vaccine dose. Persons administered single-antigen hepatitis A vaccine often will have detectable anti-HAV by 2 weeks after the first vaccine dose; the proportion of persons who will have detectable anti-HAV at 2 weeks might be lower when lower vaccine dosages are used (e.g., in TWINRIX). However, no data are available regarding the risk for hepatitis A among persons vaccinated 2 to 4 weeks before departure. Because protection might not be complete until 4 weeks after vaccination, for optimal protection, persons traveling to an area in which risk is high <4 weeks after the initial dose also may be administered IG (0.02 mL/kg), but at a different anatomic injection site. Travelers departing in <4 weeks who do not or cannot receive IG should nonetheless receive hepatitis A vaccine and be informed that they might not be optimally protected from acquiring hepatitis A in the immediate future (i.e., subsequent 2 to 4 weeks). Completion of the vaccine series according to the licensed schedule (Tables 2 to 4 in the original guideline document) is necessary for long-term protection.
Travelers who are allergic to a vaccine component or who elect not to receive vaccine should receive a single dose of IG (0.02 mL/kg), which provides effective protection against hepatitis A for up to 3 months (Table 1). Travelers whose travel period is >2 months should be administered IG at 0.06 mL/kg; administration must be repeated if the travel period is >5 months (Table 1).
Men Who Have Sex with Men (MSM)
MSM (both adolescents and adults) should be vaccinated. Prevaccination testing is not indicated for the vaccination of adolescents and young adults in this population but might be warranted for older adults (see "Prevaccination Serologic Testing for Susceptibility" in the original guideline document). Studies have suggested that the majority of MSM would accept hepatitis A vaccination if recommended by their providers. Health-care providers in primary-care and specialty medical settings in which MSM receive care should offer hepatitis A vaccine to patients at risk. Implementation strategies to overcome barriers and increase coverage (e.g., use of standing orders) should be considered.
Users of Injection and Noninjection Drugs
Vaccination is recommended for users of injection and noninjection illicit drugs. Prevaccination testing is not indicated for the vaccination of adolescent users of illicit drugs but might be warranted for certain adults. The need might depend on the particular characteristics of the population of drug users, including the type and duration of drug use. Providers should obtain a thorough history to identify patients who use or are at risk for using illicit drugs and might benefit from hepatitis A vaccination. Implementation strategies to overcome barriers and increase coverage (e.g., use of standing orders) should be considered.
Persons Who Have Occupational Risk for Infection
Persons who work with HAV-infected primates or with HAV in a research laboratory setting should be vaccinated. Studies conducted among U.S. workers exposed to raw sewage do not indicate increased risk for HAV infection. No other populations have been demonstrated to be at increased risk for HAV infection because of occupational exposure.
Persons with Clotting-Factor Disorders
Susceptible persons who are administered clotting-factor concentrates, especially solvent-detergent--treated preparations, should receive hepatitis A vaccine. Changes in clotting factor preparation practices and donor screening have greatly reduced the risk for hepatitis A for recipients of clotting factors.
Vaccination of Persons with Chronic Liver Disease
Susceptible persons with chronic liver disease should be vaccinated. Available data do not indicate a need for routine vaccination of persons with chronic hepatitis B virus (HBV) or hepatitis C virus (HCV) infections without evidence of chronic liver disease. Susceptible persons who are either awaiting or have received liver transplants should be vaccinated.
Hepatitis A Vaccination During Outbreaks
The frequency of large communitywide outbreaks has diminished considerably since implementation of the recommended childhood hepatitis A vaccination programs. Implementation of the recommendations in this report should further reduce occurrence of outbreaks. If communitywide outbreaks occur, accelerated vaccination may be considered as an additional control measure. Factors to consider in deciding whether to initiate an outbreak-control vaccination program include the feasibility of rapidly vaccinating the target population of children, adolescents, or young adults, and program cost. Ongoing vaccination of children should be sustained to maintain high levels of immunity and prevent future epidemics.
Limited outbreaks, especially those involving adults at increased risk (e.g., illicit drug users or MSM), are likely to continue to occur until higher vaccine coverage is achieved in these populations. Vaccination programs to control these outbreaks have been difficult to implement. Programs to control hepatitis A outbreaks among users of illicit drugs, especially methamphetamine, that focused on vaccination in county jails and similar venues (e.g., court-ordered diversion programs) have met with some limited success, at least in terms of the provision of vaccine. In general, efforts to control and prevent hepatitis A outbreaks among adults in these populations should be focused primarily on initiating and sustaining routine vaccination of these persons.
The frequency of outbreaks in child care centers has also decreased in recent years and should continue to decrease with more widespread vaccination of young children. Limited data exist regarding the role of hepatitis A vaccine in controlling outbreaks in these settings. If outbreaks are recognized in child care centers, use of IG as recommended is effective in limiting transmission to employees and families of attendees (see "Postexposure Prophylaxis with IG," below). Previously unvaccinated children receiving postexposure prophylaxis with IG should also receive hepatitis A vaccine.
Persons who work as food handlers can contract hepatitis A and potentially transmit HAV to others. One national economic analysis concluded that routine vaccination of all food handlers would not be economical from a societal or restaurant owner's perspective. Nonetheless, to decrease the frequency of evaluations of food handlers with hepatitis A and the need for postexposure prophylaxis of patrons, consideration may be given to vaccination of employees who work in areas where state and local health authorities or private employers determine that such vaccination is appropriate. Food handlers who receive hepatitis A vaccine should be provided with a record of the immunization. Those who do not should be informed of the signs and symptoms of hepatitis A and taught food preparation practices that reduce the risk for fecal contamination.
Postexposure Prophylaxis with IG
Persons who have been recently exposed to HAV and who have not previously received hepatitis A vaccine should be administered a single dose of IG (0.02 mL/kg) as soon as possible. Efficacy when administered >2 weeks after exposure has not been established. Persons who have been administered 1 dose of hepatitis A vaccine at >1 month before exposure to HAV do not need IG.
Because hepatitis A cannot be reliably diagnosed on clinical presentation alone, serologic confirmation of HAV infection in index patients by IgM anti-HAV testing is recommended before postexposure treatment of contacts. Screening of contacts for immunity before administering IG is not recommended because screening would result in delay.
If hepatitis A vaccine is recommended for a person being administered IG (e.g., a person with a recent exposure but also an indication for vaccination), it may be administered simultaneously with IG at a separate anatomic injection site. Unlike IG, hepatitis A vaccine is not licensed for use as postexposure prophylaxis. The completion of studies comparing IG with hepatitis A vaccine for postexposure prophylaxis is needed before vaccine can be recommended in this setting. IG should be administered to previously unvaccinated persons in the following situations.
Close Personal Contact
IG should be administered to all previously unvaccinated household and sexual contacts of persons with serologically confirmed hepatitis A. In addition, persons who have shared illicit drugs with a person who has serologically confirmed hepatitis A should receive IG and hepatitis A vaccine. Consideration should also be given to providing IG to persons with other types of ongoing, close personal contact with a person with hepatitis A (e.g., regular babysitting).
Child Care Centers
IG should be administered to all previously unvaccinated staff and attendees of child care centers or homes if 1) one or more cases of hepatitis A are recognized in children or employees or 2) cases are recognized in two or more households of center attendees. In centers that do not provide care to children who wear diapers, IG need be administered only to classroom contacts of an index patient. When an outbreak occurs (i.e., hepatitis A cases in three or more families), IG also should be considered for members of households that have children (center attendees) in diapers. Hepatitis A vaccine may be administered at the same time as IG for children receiving postexposure prophylaxis in child care centers.
Common-Source Exposure
If a food handler receives a diagnosis of hepatitis A, IG should be administered to other food handlers at the same establishment. Because common-source transmission to patrons is unlikely, IG administration to patrons typically is not indicated but may be considered if 1) during the time when the food handler was likely to be infectious, the food handler both directly handled uncooked foods or foods after cooking and had diarrhea or poor hygienic practices, and 2) patrons can be identified and treated <2 weeks after the exposure. In settings in which repeated exposures to HAV might have occurred (e.g., institutional cafeterias), stronger consideration of IG use might be warranted. In the event of a common-source outbreak, IG should not be administered to exposed persons after cases have begun to occur because the 2-week period during which IG is effective will have been exceeded.
Schools, Hospitals, and Work Settings
IG is not routinely indicated when a single case occurs in an elementary or secondary school, an office, or other work settings, and the source of infection is outside the school or work setting. Similarly, when a person who has hepatitis A is admitted to a hospital, staff should not routinely be administered IG; instead, careful hygienic practices should be emphasized. IG should be administered to persons who have close contact with index patients 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.
