Vaccines for Premature Babies

Preterm babies are infants born before 37 weeks of pregnancy. During the last trimester of pregnancy, the fetus receives antibodies against various bacteria and viruses from the mother through the placenta. Because preterm babies are born before the end of pregnancy, they receive fewer antibodies through the placenta than babies born after a full-term pregnancy.

To protect preterm babies from diseases, it is very important that they receive all the routine vaccinations recommended for babies, including the flu vaccine, with adjustments to the timing of some vaccines.

Immunization Schedule for Preterm Babies: Based on Chronological Age

Preterm babies are vaccinated according to their chronological age — meaning the age calculated from their date of birth (rather than their corrected age, which is the age they would have been if they had been born after a full-term pregnancy). Vaccines are given based on each preterm baby's gestational age at birth, birth weight, and specific health condition.

For 2 of the routine vaccinations, the timing is different:

• Rotavirus vaccine: Preterm babies who are still hospitalized at 2 months of age will receive the first dose of the rotavirus vaccine after discharge from the hospital, according to their chronological age.
• Hepatitis B vaccine: The first dose of the hepatitis B vaccine (viral hepatitis B) is intended to be given shortly after birth, but the vaccine is less effective in preterm babies weighing less than 2 kg. Therefore, this vaccination is postponed until discharge from the hospital, until they reach a weight of 2 kg, or until they reach 1 month of age (chronological age), whichever comes first. The second dose of the hepatitis B vaccine will be given 1 month after the first dose. A booster dose will be given 5 months after the second dose.
• Immunization schedule for preterm babies born to mothers who are carriers of the virus that causes hepatitis B: Preterm babies born to mothers who are carriers of HBV, the virus that causes hepatitis B, will receive the vaccine shortly after birth to prevent transmission from the mother. If a preterm baby was born weighing less than 2 kg, the active vaccine given immediately after birth will not count as part of the routine vaccination series. The full vaccination series, which includes 3 doses, will begin when the baby reaches a weight of 2 kg, reaches 1 month of age, or is discharged from the hospital, whichever comes first.

• Passive vaccine against hepatitis B: When the mother is a carrier of HBV, it is recommended that the baby, especially a preterm baby, receive passive vaccine against hepatitis B. This vaccine is given in addition to the active hepatitis B vaccine and contains ready-made antibodies specific to HBV, but it does not cause the body to produce antibodies on its own.

Additional Recommended Vaccinations

• RSV vaccine: RSV causes respiratory illnesses that can put preterm babies and infants at risk. The vaccine is passive, meaning it contains antibodies specific to RSV.

  The vaccine is given to all preterm babies and infants in a single shot during the first RSV season (August through March).

  Infants and toddlers who are at increased risk of severe RSV illness are also eligible for vaccination during the second RSV season.

  Information about RSV immunization