From the Guidelines
A reactive Hepatitis A antibody test indicates that a person has been previously infected with the Hepatitis A virus or has been successfully vaccinated against it, meaning they have immunity to the disease. No special precautions are needed since the person is immune and cannot contract or spread Hepatitis A. This immunity is typically lifelong, so no booster vaccinations are required. The test specifically detects IgG antibodies, which develop during infection or after vaccination and remain in the bloodstream for years. It's essential to understand that a reactive result is actually good news, as it means the person is protected against future Hepatitis A infections. If someone has a reactive test but is unsure if they were previously vaccinated, they can consider their immunity established and do not need vaccination 1. However, they should still practice good hygiene and may want to consider vaccination against other forms of viral hepatitis, such as Hepatitis B, if they haven't already been immunized. Some key points to consider include:
- The Centers for Disease Control and Prevention (CDC) recommends hepatitis A vaccination for certain groups, including men who have sex with men, persons who use injection or noninjection illicit drugs, and persons traveling to or working in countries with high or intermediate endemicity of hepatitis A 1.
- The vaccine is typically administered in a 2-dose schedule, with the second dose given 6 to 12 months after the first dose 1.
- Immune globulin (IG) can be considered in addition to vaccine for older adults, immunocompromised persons, and persons with chronic liver disease or other chronic medical conditions who are traveling to an area within 2 weeks 1. It's crucial to follow the recommended vaccination schedule and consider individual factors, such as travel plans and underlying medical conditions, when determining the best course of action for hepatitis A prevention. In general, a reactive Hepatitis A antibody test is a positive result, indicating immunity to the disease, and no further action is needed beyond practicing good hygiene and considering vaccination against other forms of viral hepatitis if necessary.
From the Research
Reactive Hepatitis A Antibody
A reactive Hepatitis A (Hep A) antibody indicates that an individual has been exposed to the Hepatitis A virus (HAV) and has developed immunity to the virus. This can occur through either natural infection or vaccination.
Indications of Reactive Hepatitis A Antibody
- The presence of HAV antibodies in an individual's blood, as detected by commercial immunoassays, indicates that the person has been exposed to the virus and has developed immunity 2.
- A reactive Hep A antibody can also indicate that an individual has received immune globulin (Ig) or a Hepatitis A vaccine, which can provide protection against HAV infection 3, 4.
Precautions to be Taken
- Individuals with a reactive Hep A antibody should still take precautions to prevent the spread of HAV to others, especially in high-risk settings such as childcare centers or areas with poor sanitation 4, 5.
- Vaccination is recommended for individuals who are at high risk of HAV infection, such as travelers to areas with high endemic rates, children living in areas with high endemic rates, and patients with chronic liver disease 5.
- Immune globulin is recommended for postexposure prophylaxis, especially for individuals who have been exposed to HAV and are at high risk of infection 3, 5.
Distinction between Natural Infection and Vaccination
- Serological approaches can be used to distinguish between immune response to Hepatitis A vaccine and natural infection, such as measuring antibodies against the non-structural genome region of the virus (P2 or P3) 6.
- Individuals who have received a Hepatitis A vaccine may not have detectable levels of HAV antibodies when tested by commercial immunoassays, but may still have low titers of HAV antibody that can be detected by more sensitive immunoassays and neutralization assays 2.