According to routine immunization guidelines, when should the hepatitis B vaccine be administered after birth?

The correct timing for administering the hepatitis B vaccine after birth is critical for ensuring an effective immune response and preventing hepatitis B infection. The first dose of the vaccine is typically given at birth, followed by subsequent doses at one month and six months of age. This schedule allows the infant's immune system to build adequate immunity against the hepatitis B virus while also considering the natural decline of maternal antibodies.

When looking at the choices, the second dose following the initial birth dose at one month is essential because it allows the infant to develop an immune response earlier, while the six-month mark ensures longer-lasting immunity. The other options provide incorrect combinations of timing that do not align with the established immunization guidelines, as they either miss the critical early administration window or do not follow the recommended intervals for optimal vaccination. This reinforces the importance of adhering to the specific scheduling recommended by health authorities to ensure comprehensive protection against hepatitis B.