From the Guidelines
A non-reactive Hepatitis A (HAV) antibody test result indicates that the patient lacks sufficient immunity against hepatitis A virus, suggesting the need for vaccination or revaccination, even if the patient received the Hepatitis A vaccine 5 years ago.
Key Considerations
- The duration of immunity after Hepatitis A vaccination can vary, but protective levels of anti-HAV can persist for >25 years in adults and >14--20 years in children 1.
- However, antibody levels can wane over time, and a non-reactive test result may indicate the need for a booster dose to restore immunity 1.
- The recommended dose for a booster can vary depending on the vaccine used, such as 1440 EL.U. for Havrix or 50 U for Vaqta.
Clinical Implications
- A non-reactive Hepatitis A antibody test result in a patient who received the vaccine 5 years ago may not necessarily indicate a need for immediate revaccination, as protective anti-HAV antibody levels can persist for almost 11 years 1.
- However, factors such as anti-HAV endemicity levels, population-specific factors, and the amount of antigen given in the primary vaccine dose should be considered when determining the need for a booster dose 1.
- In general, a booster dose of the Hepatitis A vaccine can be considered to restore immunity in patients with a non-reactive antibody test result, especially if they are at high risk of exposure to the virus 1.
From the FDA Drug Label
The duration of immunity following a complete schedule of immunization with HAVRIX has not been established.
A non-reactive Hepatitis A (HAV) antibody test result may indicate the need for vaccination, even if the patient received the Hepatitis A vaccine 5 years ago, since the duration of immunity is unknown 2.
From the Research
Hepatitis A Vaccination and Antibody Test Results
- A non-reactive Hepatitis A (HAV) antibody test result may indicate the need for vaccination, even if the patient received the Hepatitis A vaccine 5 years ago 3.
- The level of anti-HAV antibodies can wane over time, and a non-reactive test result may not necessarily indicate a lack of immunity 4, 3.
- Studies have shown that individuals who have lost protective antibodies after primary vaccination can still respond to revaccination with HAV vaccines 3.
Interpretation of Antibody Test Results
- A non-reactive anti-HAV IgM test result does not necessarily indicate a lack of immunity, as some individuals may have a non-reactive IgM test result but still have protective antibodies 5.
- The sensitivity of anti-HAV total assays may be higher than that of anti-HAV IgM assays, which can lead to non-reactive IgM test results in individuals with protective antibodies 5.
Revaccination and Booster Shots
- Revaccination with HAV vaccines can induce a rapid and sufficient serological response in individuals who have lost protective antibodies after primary vaccination 3.
- A single dose of HAV revaccination may be sufficient to provide rapid and sufficient seroresponses for HAV during an outbreak of acute hepatitis A 3.
- The need for booster shots may depend on various factors, including the individual's immune status and the level of anti-HAV antibodies 4, 3.