When Should My Baby Get their Vaccines?

When Should Preterm Babies Get Vaccines? (Please discuss all your concerns with your doctor. This information is not meant to take the place of your doctor's recommendation.)

One of the most common questions in the NICU is:“Do premature babies follow the same vaccine schedule?”

The key point:

Preterm infants should receive vaccines based on their chronological age (their actual age since birth), NOT their corrected gestational age.

• The Centers for Disease Control and Prevention and American Academy of Pediatrics recommend that clinically stable preterm infants follow the same immunization schedule as full-term infants.

Why this matters

Preterm infants are actually at higher risk of severe infection because:

• Immature immune systems

• Less transplacental antibody transfer

• Increased exposure in the NICU

Delaying vaccines prolongs vulnerability to serious, preventable diseases.

Are vaccines safe in preterm infants?

Yes — and this is strongly supported by evidence.

What studies show:

• Preterm infants mount protective immune responses when vaccinated on schedule.

• Routine vaccines (including combination vaccines and pneumococcal) are safe and well tolerated, even in very low birth weight infants.

• Large reviews show good immunogenicity with acceptable safety profiles, even in extremely premature infants.

What about apnea after vaccines?

This is often a concern in the NICU.

• Some studies show increased short, self-limited apnea events after 2-month vaccines in hospitalized preterm infants

• BUT importantly:

  • Events are brief and not associated with serious complications

  • Benefits of vaccination far outweigh the risks 

Because of this, many NICUs monitor extremely premature infants for 24–48 hours after their first vaccines.

Important exceptions

• Hepatitis B vaccine

  • If birth weight <2000 g and mom is Hep B negative → delay until 1 month or discharge

  • If mom is Hep B positive or unknown → give at birth (with HBIG)

• Rotavirus vaccine

  • Usually deferred until NICU discharge to avoid viral spread in the unit

Take-home message

✨ Preterm babies:

• Should be vaccinated on time using their chronological age

• Respond well to vaccines

• Tolerate vaccines safely

• Need protection even more urgently than term infants

Bottom line

Delaying vaccines in premature infants is not protective — it increases risk.Timely immunization is one of the most important ways we protect this vulnerable population.