Very low birth weight infants have only few adverse events after timely immunization

Area of Science:

• Neonatal Medicine
• Pediatric Immunology
• Vaccinology

Background:

• Premature infants require vaccination at standard ages, irrespective of weight or corrected gestational age.
• Physicians express concerns regarding potential severe adverse events following infant vaccinations.

Purpose of the Study:

• To assess the safety and adverse events of vaccinating premature infants born weighing less than 1500 grams.
• To identify risk factors associated with adverse events in this vulnerable population.

Main Methods:

• A prospective observational study included 473 premature infants (birth weight < 1500g).
• Adverse events monitored included cardiorespiratory events (apnea, bradycardia), local reactions, and fever.
• Three different vaccination combinations were administered over the study period.

Main Results:

• The median birth weight was 910g, with a median gestational age of 27.6 weeks.
• At vaccination, the median gestational age was 37.4 weeks.
• Local reactions/fever occurred in 2.8% of infants, while cardiorespiratory events (apnea/bradycardia) occurred in 10.8%.
• Younger infants at immunization were significantly more prone to apnea, which increased the risk of bradycardia (OR 6.4).
• Infants with higher-grade hemorrhages or periventricular leukomalacia did not show increased adverse events, except for fever.

Conclusions:

• Vaccinating premature infants under 1500g at the appropriate age is a safe practice.
• The incidence of cardiorespiratory events during vaccination is associated with an earlier gestational age at birth.