Panel A: HBV vaccination schedule in India: birth dose within 24 hours, 6-week, 10-week, and 14-week pentavalent doses; recombinant HBsAg subunit vaccine; prevention of vertical transmission and hepatocellular carcinoma.. Panel B: Post-vaccination serology showing isolated anti-HBs positivity, negative HBsAg, negative anti-HBc IgM, negative anti-HBc IgG, and protective anti-HBs level >= 10 mIU/mL.. Panel C: Natural HBV serology timeline showing HBsAg, anti-HBc IgM, anti-HBc IgG, anti-HBs, and the highlighted window period.. Panel D: Comparison table of vaccinated pattern, recovered natural infection pattern, and acute HBV infection pattern using HBsAg, anti-HBc IgM, anti-HBc IgG, and anti-HBs.. Panel E: Post-exposure prophylaxis pathways for needlestick from HBsAg-positive source and neonate of HBsAg-positive mother, showing HBIG plus vaccination timing..
The hepatitis B vaccine is a recombinant subunit vaccine containing only HBsAg expressed in yeast (Saccharomyces cerevisiae). It is the only vaccine against a human cancer (hepatocellular carcinoma).
Schedule in India (National Immunization Schedule): - Birth dose (within 24 hours) — crucial to prevent vertical transmission - 6 weeks, 10 weeks, 14 weeks — as pentavalent vaccine (DTP-HepB-Hib)
Post-vaccination serology: Only anti-HBs is generated (no anti-HBc — no natural infection). Protective level: anti-HBs ≥10 mIU/mL.
Post-exposure prophylaxis (HBIG + vaccine): - Needlestick from HBsAg-positive source: Hepatitis B Immunoglobulin (HBIG) within 24 hours + start/complete vaccine series - Neonate of HBsAg-positive mother: HBIG + birth dose vaccine within 12 hours
HBV Serology: Vaccine vs Natural Infection
Panel A: HBV serology timeline showing HBsAg, anti-HBc IgM, anti-HBc IgG, anti-HBs, and highlighted window period. Panel B: Vaccinated pattern showing anti-HBs alone positive with HBsAg, anti-HBc IgM, and anti-HBc IgG negative. Panel C: Recovered natural infection pattern showing anti-HBs and anti-HBc IgG positive with HBsAg and anti-HBc IgM negative. Panel D: Acute HBV infection pattern showing HBsAg and anti-HBc IgM positive with anti-HBs negative. Panel E: Clinical pearl callout showing window-period trap, negative HBsAg limitation, anti-HBc IgM testing, and blood bank anti-HBc screening.
CLINICAL PEARL
The window period trap: In early acute HBV, HBsAg may become undetectable (cleared) before anti-HBs appears — the 'window period.' During this time, the ONLY marker present is anti-HBc IgM. Blood banks screen for anti-HBc to catch window-period donors. In a patient with acute hepatitis, negative HBsAg does NOT exclude HBV — always send anti-HBc IgM when clinical suspicion is high.
