When is the hepatitis B vaccine typically administered to newborns, and why is immunization important?

• A. At 6 weeks; to boost early immunity
• B. At 2 years; to protect long-term
• C. Within 24 hours of birth; prevents hepatitis B infection and its long-term complications
• D. Only if exposed; post-exposure prophylaxis

Answer: (C)

Administering the hepatitis B vaccine within 24 hours of birth blocks the virus at the very start of life. Giving the birth dose primes the newborn’s immune system to produce protective antibodies before exposure can take hold during delivery, greatly reducing the chance of infection. Since hepatitis B infection in infancy often becomes chronic and can lead to serious long-term liver disease, preventing it from the outset cuts this lifelong risk. The newborn vaccine is the first in a series (with later doses to complete immunity). If the mother is known to have hepatitis B, the infant may also receive hepatitis B immune globulin at birth for added protection. Waiting to vaccinate later or only after exposure misses this critical immediate window and leaves the infant vulnerable.