Vaccines for Preterm Infants

Preemies are babies born before week 37 of pregnancy. In the last trimester of pregnancy, the fetus receives from the mother, through the placenta, antibodies against various bacteria and viruses. Because premature babies are born before the end of pregnancy, they receive fewer antibodies through the placenta in comparison with babies born after a full term of pregnancy.

To protect these premature babies from diseases, it is extremely important that they receive the entire routine vaccines recommended for babies, including the flu vaccine, with adjustments to some vaccination dates. It is also recommended that premature babies be vaccinated against the RSV virus.

Dates for the routine vaccines for premature babies: based on chronological age

Premature babies are vaccinated according to their chronological age - the age calculated based on the date of birth (and not the adjusted age, which is their age had they been born after a full term of pregnancy). The vaccines are given based on the date of birth, birth weight and state of health of the premature baby.

The dates of administration of two of the routine vaccines have changed:

• Rotavirus vaccine: premature babies who are still hospitalized at the age of two months will receive the first does of the rotavirus vaccine after they are discharged from the hospital, based on the chronological age.
• Hepatitis B vaccine: the first dose of the hepatitis B vaccine (type B viral inflammation) should be given shortly after birth but for premature babies weighing less than 2 kg, the vaccine is less effective. The date of vaccination is postponed until discharge from the hospital, or until the baby reaches a weight of 2 kg or turns one month old (chronologically) – whichever is earlier. The second dose of the hepatitis B vaccine is given one month after the first dose. A booster dose is given 5 months after the second dose.
• Schedule of vaccination of a premature baby born to a mother who is a carrier of hepatitis B: premature babies born to mothers who are carriers of the HBV virus, which causes hepatitis B, will receive the vaccine shortly after birth, to prevent contraction by the mother. If the premature baby's birth weight is less than 2 kg, the active vaccine given immediately after birth will not be considered part of the immunization schedule. The complete series of vaccination, which includes 3 doses, will begin when the baby reaches a weight of 2 kg or turns one month old, or upon discharge from the hospital, whichever is earlier.
• Passive hepatitis B vaccine: if the mother is a carrier of the HBV virus, the recommendation is to vaccinate the baby, particularly if the baby is born prematurely, with a passive hepatitis B vaccine. This vaccine is given in addition to the active hepatitis B vaccine and contains prepared antibodies specific to the HBV virus but does not cause the body to produce antibodies itself.

Other recommended vaccines

• Passive RSV vaccine - Palivizumab: RSV is a common cause of respiratory tract infections in infants, and by the age of two, most babies contract it. Premature babies (and babies with congenital heart and lung diseases) are at a higher risk of developing a serious illness and complications. They must be vaccinated with the passive RSV vaccine, which contains specific antibodies against the virus but does not cause the body to produce them itself.
  The RSV vaccine is given in the first year or two of the baby’s life. As the virus is generally active in the winter, 5 doses are given during the active season - one dose a month from November 1st to March 31st.