Hepatitis A secondary prevention
CDC guidelines for postexposure protection against Hepatitis A
Until recently, an injection of immune globulin (IG) was the only recommended way to protect people after they have been exposed to Hepatitis A virus. In June 2007, U.S. guidelines were revised to allow for Hepatitis A vaccine to be used after exposure to prevent infection in healthy persons aged 1–40 years.
Persons who have recently been exposed to HAV and who have not been vaccinated previously should be administered a single dose of single-antigen Hepatitis A vaccine or IG (0.02 mL/kg) as soon as possible, within 2 weeks after exposure. The guidelines vary by age and health status:
- For healthy persons aged 12 months–40 years, single-antigen Hepatitis A vaccine at the age-appropriate dose is preferred to IG because of vaccine’s advantages, including long-term protection and ease of administration, as well as the equivalent efficacy of vaccine to IG.
- For persons aged >40 years, IG is preferred because of the absence of information regarding vaccine performance in this age group and because of the more severe manifestations of Hepatitis A in older adults. Vaccine can be used if IG cannot be obtained. The magnitude of the risk of HAV transmission from the exposure should be considered in decisions to use vaccine or IG in this age group.
- For children aged <12 months, immunocompromised persons, persons with chronic liver disease, and persons who are allergic to the vaccine or a vaccine component, IG should be used.
Indications for Postexposure Prophylaxis
- Close personal contacts. Close personal contacts of persons with serologically confirmed Hepatitis A (i.e., through a blood test), including:
- Household and sex contacts
- Persons who have shared illicit drugs with someone with Hepatitis A
Consideration should also be given to providing IG or Hepatitis A vaccine to persons with other types of ongoing, close personal contact with a person with Hepatitis A (e.g., a regular babysitter or caretaker).
- Child-care center staff, attendees, and attendees' household members
- PEP 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 provide care only to older children who no longer wear diapers, PEP need be administered only to classroom contacts of the index patient (i.e., not to children or staff in other classrooms).
- When an outbreak occurs (i.e., Hepatitis A cases in three or more families), PEP should also be considered for members of households that have diaper-wearing children attending the center.
- Persons exposed to a common source, such as an infected food handler. If a food handler receives a diagnosis of Hepatitis A, PEP should be administered to other food handlers at the same establishment. Because transmission to patrons is unlikely, PEP 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 within 2 weeks of exposure.
In settings in which repeated exposures to HAV might have occurred, such as institutional cafeterias, stronger consideration of PEP use might be warranted.
- Case of Hepatitis A is found in a school, hospital, or office setting. If a single case of Hepatitis A is identified in a school (other than a child care setting in which children wear diapers), office, or other work setting, and if the source of infection is outside the school or work setting, PEP (i.e., injection of IG or Hepatitis A vaccine) is not routinely recommended. Similarly, when a person who has Hepatitis A is admitted to a hospital, staff should not routinely be administered PEP; instead, careful hygienic practices should be emphasized.
However, if it is determined that Hepatitis A has been spread among students in a school or among patients and staff in a hospital, PEP should be administered to unvaccinated persons who have had close contact with an infected person.