When should the second dose of hepatitis B vaccine be given to newborns?

Under normal circumstances, the second dose of hepatitis B vaccine for newborns should be administered when they are one month old. If the newborn shows any health abnormalities at one month of age, the vaccination schedule may be appropriately delayed.

Typically, the first dose of hepatitis B vaccine should be given within 24 hours after birth, and the second dose should be administered at one month of age to help prevent hepatitis B infection. If the newborn develops symptoms such as fever, eczema, or diarrhea at one month of age, the timing of the second dose may be postponed until the illness resolves or symptoms improve. It is generally recommended to delay vaccination by 1–2 weeks, but not for an extended period. If the second dose is delayed beyond two months—meaning administration after 60 days or even six months from birth—the infant may fail to develop sufficient antibodies, resulting in inadequate disease protection.

It is advisable to follow the standard vaccination schedule as soon as the infant's health permits. After vaccination, if adverse reactions such as pain, redness, or swelling at the injection site, or fever occur, prompt medical attention is recommended. Treatment should be carried out under a doctor’s guidance to prevent worsening of symptoms.