Not being immune to Hepatitis B means the body lacks the necessary defenses to fight off an infection from the Hepatitis B virus (HBV). This status indicates a person is fully susceptible to contracting this serious viral liver infection if exposed. Understanding this test result is the first step in gaining protection against a disease that can have severe long-term health consequences.
Understanding Hepatitis B Transmission
The Hepatitis B virus is transmitted when blood, semen, or other body fluids from an infected person enter the body of someone who is not infected. A primary route of transmission is from mother to child during birth, especially in areas where the virus is common. Transmission also occurs through sexual contact with an infected partner, particularly without barrier protection. Sharing contaminated needles, syringes, or drug preparation equipment is another common way the virus spreads.
The virus is highly infectious and can survive on surfaces outside the body for at least seven days. Less common, but still possible, transmission routes include sharing personal items like razors or toothbrushes that may have traces of blood. HBV is not spread through casual contact, such as hugging, kissing, coughing, sneezing, or sharing eating utensils. The virus is also not transmitted through contaminated food or water.
Interpreting Non-Immunity Markers
A blood test known as the Hepatitis B Panel is used to determine immunity, and the most telling result for susceptibility is the status of the Hepatitis B Surface Antibody (HBsAb or anti-HBs). A negative or non-reactive HBsAb result means the body does not have protective antibodies against the virus. The protective level of this antibody is considered to be 10 milli-International Units per milliliter (mIU/mL) or higher. Therefore, any result below this threshold indicates a lack of protective immunity, leaving the person susceptible to infection.
This lack of HBsAb is seen in people who have never been vaccinated and have never been exposed to the virus. To confirm this susceptible status, other markers are checked, such as the Hepatitis B Surface Antigen (HBsAg), which should also be negative, indicating no current active infection. The Hepatitis B Core Antibody (HBcAb) is also negative in a susceptible person, confirming there has been no past exposure to the core of the virus. A negative result across all three markers confirms a person is uninfected but vulnerable.
The Health Risks of Being Unprotected
Being unprotected carries the risk of contracting the Hepatitis B virus, which leads to an infection that can be either acute or chronic. An acute infection is a short-term illness occurring within the first six months after exposure. Most healthy adults who contract HBV will clear the virus from their body and develop lifelong immunity, with approximately 95% of infected adults recovering completely.
However, a small percentage of adults, and a much higher percentage of infants and young children, will develop a chronic infection, where the virus persists in the body for six months or longer. Chronic Hepatitis B is the main cause of long-term complications, even if the person remains asymptomatic for many years. Persistent viral presence can lead to serious liver damage, including cirrhosis. Chronic HBV infection is a leading cause of hepatocellular carcinoma, a form of liver cancer.
Gaining Protection Through Vaccination
The most effective way to gain protection against the Hepatitis B virus is through vaccination. The standard vaccination protocol involves a series of two or three doses administered over a period of several months. The vaccine works by introducing the surface antigen of the virus, prompting the immune system to produce the protective HBsAb.
After completing the full series, a follow-up blood test for HBsAb is performed to confirm that the person has achieved “seroconversion,” meaning they have developed a protective level of antibodies. This testing is done one to two months after the final dose of the vaccine series. A successful response, or seroprotection, is indicated by an HBsAb level of 10 mIU/mL or greater.
In some cases, individuals may have received the vaccine but their immunity level has waned over time. Others may be classified as “non-responders,” meaning they failed to produce a protective antibody level after completing the initial series. Non-responders may be advised to undergo a second complete vaccination series to attempt to achieve immunity. If a second series fails, the individual is considered a persistent non-responder and should be counseled on precautions due to their continued susceptibility to the virus.