Hepatitis B Virus (HBV) Serology Markers
📌 Hepatitis B Surface Antigen (HBsAg) is the first serologic marker detected, appearing approximately one month post-exposure (ranging from one week to nine weeks).
🩺 Symptoms of acute HBV infection typically manifest around twelve weeks post-exposure, with a range of 9 to 21 weeks.
🦠 Hepatitis B e-Antigen (HBeAg) presence correlates with higher viral titers and greater infectivity, whereas anti-HBe indicates lower viral levels.

Diagnosis of Acute vs. Chronic Infection
📌 Acute hepatitis B is diagnosed by detecting IgM class antibody to hepatitis B core antigen (IgM anti-HBc), which typically becomes undetectable within six to nine months.
🛡️ Antibody to hepatitis B surface antigen (anti-HBs) appears during convalescence, indicating recovery and immunity from reinfection.
🔄 Chronic HBV infection is diagnosed if HBsAg, HBeAg, or HBV DNA are positive on at least two separate samples six months apart, or if one is positive with a negative IgM anti-HBc.

Vaccination and Immunity Status
💉 Successful HBV vaccination results in anti-HBs production, with sero-protection defined as an anti-HBs level of $\ge 10$ milli-International Units per milliliter (mIU/mL) after completing the vaccine series.
⏱️ Immunity is likely maintained even if anti-HBs levels naturally decline below $10$ mIU/mL without re-exposure.
🧪 A positive anti-HBs alone generally indicates immunity following vaccination (at least three doses of the vaccine).

Key Points & Insights
➡️ The window period occurs after HBsAg disappears but before anti-HBs appears, during which only IgM anti-HBc and total anti-HBc may be present on routine tests.
➡️ Individuals recovering from acute infection will be HBsAg and HBV DNA negative by 15 weeks after symptom onset.
➡️ In chronic infection, serologic testing will persistently show HBsAg and total anti-HBc (total antibody to hepatitis B core antigen).
➡️ A negative result for HBsAg, total anti-HBc, IgM anti-HBc, and anti-HBs indicates the person is never infected and therefore susceptible.

📸 Video summarized with SummaryTube.com on Dec 07, 2025, 22:15 UTC