From the Guidelines
Hepatitis B surface antibody (anti-HBs) is a crucial test for determining immunity to hepatitis B, and a positive result (typically greater than 10 mIU/mL) indicates immunity, either from past infection or successful vaccination, as stated in the most recent guidelines 1. The hepatitis B surface antibody test is used to detect antibodies against the hepatitis B virus surface antigen, which indicates either past infection with hepatitis B or successful vaccination against the virus.
- A positive result typically means immunity to hepatitis B, either from recovery from a previous infection or from vaccination.
- This immunity is generally considered lifelong after natural infection, though vaccine-induced immunity may wane over time in some individuals.
- If the test is negative, the individual lacks immunity and may need vaccination, which consists of a series of three shots given over 6 months (at 0,1, and 6 months).
- For immunocompromised patients or those with specific risk factors, additional testing or booster doses may be recommended, as suggested by recent studies 1. This antibody test is different from the hepatitis B surface antigen (HBsAg) test, which detects the actual virus and indicates active infection.
- Healthcare providers use these tests to determine infection status, immunity status, and appropriate prevention or treatment strategies for hepatitis B, as outlined in the guidelines 1.
- Patients with malignancies who are HBsAg positive and/or HBcAb positive are at risk for HBV reactivation with cytotoxic chemotherapy, and approximately 20%–50% of patients with HBsAg positivity and 3%–45% with HBcAb positivity develop HBV reactivation, as reported in the literature 1. Therefore, it is essential to test for hepatitis B surface antibody (anti-HBs) to determine immunity status and to follow the guidelines for prevention and treatment of HBV reactivation in patients with cancer, as recommended by the most recent guidelines 1.
From the Research
Hepatitis B Surface Antigen and Antibody
- The presence of hepatitis B surface antibody (anti-HBs) in addition to hepatitis B core antibody (anti-HBc) confers protection against hepatitis B virus (HBV) infection in hepatitis B surface antigen (HBsAg)-negative patients undergoing kidney transplantation 2.
- The combination of entecavir or tenofovir with pegylated interferon-α has been investigated for long-term reduction in HBsAg levels, but there is no robust evidence that combination therapy is superior to monotherapy 3.
Treatment of Chronic Hepatitis B
- Tenofovir and entecavir are the most effective antiviral agents for chronic hepatitis B, with tenofovir being most effective in inducing undetectable levels of HBV DNA and improving liver histology 4.
- A systematic review and meta-analysis found that the risk of HBV resistance to entecavir increases over time, while tenofovir appears to have an excellent resistance profile 5.
Coexistence of HBsAg and HBsAb
- The coexistence of HBsAg and anti-HBs antibodies (HBsAb) has been documented in patients with chronic hepatitis B, and the loss of HBsAg with entecavir plus tenofovir combination has been reported in a difficult-to-treat case 6.
- The clinical implications of possible mutations in the reverse transcriptase region (rt) of HBV polymerase and the HBsAg ORF are still being explored, and the response to antiviral therapies in patients with concurrent HBsAg and HBsAb positivity is not well understood 6.