When should Hepatitis B vaccine be administered to the newborn, and what additional protection is given if mother is HBsAg positive?

• A. HepB vaccine within 24 hours of birth; if mother is HBsAg positive, give HBIG as well.
• B. Vaccine at 1 month; no HBIG needed.
• C. Vaccine at 6 months; HBIG only if infant symptomatic.
• D. No HepB vaccine in newborn period.

Answer: (A)

The key idea is protecting the newborn from hepatitis B transmission right after birth by combining immediate passive protection with active immunization. The Hepatitis B vaccine should be given to all newborns within 24 hours of birth to start the infant’s own immune response. If the mother is HBsAg positive, adding hepatitis B immune globulin (HBIG) within about 12 hours of birth provides immediate, temporary antibodies to help neutralize the virus right away, while the vaccine stimulates the baby’s own immune system for longer-term protection. Together, this plan greatly reduces the risk of perinatal transmission and the child developing chronic infection.

Choosing later vaccine timing misses the critical window for preventing transmission, and HBIG is not reserved only for symptomatic infants nor is it conditional on symptoms. Not giving any HepB vaccine in the newborn period would leave the infant unprotected from exposure at a time when transmission risk is highest.