Active Immunization of Premature and Low Birth-Weight Infants

Abstract

Preterm infants are at increased risk of disease and hospitalization from a number of vaccine-preventable diseases. However, these same infants have immunologic immaturities that may impact vaccine responses. Larger premature infants mount immune responses to vaccines similar to those of full-term infants, but very premature infants (<28-32 weeks' gestation at birth) may have specific defects in vaccine responsiveness. Although there are minor differences in immunogenicity, the immune responses to diphtheria, tetanus, pertussis, and polio antigens are similar enough between full-term and premature infants that clinical consequences are unlikely to result. However, the immunogenicity of Haemophilus influenzae type b conjugate vaccines varies widely among studies of premature infants, and may be affected by the choice of conjugate protein, inclusion in a combination vaccine, and by an infant's overall health. Pneumococcal conjugate vaccine is efficacious in larger premature infants, but little information is available about immunogenicity in smaller premature infants. Meningococcal group C conjugate vaccine appears immunogenic in even very premature infants, but the duration of immunity may be limited. Hepatitis B vaccine given at birth appears poorly immunogenic in infants with birth weights <1500-2000 g, with delay in the administration of the first dose yielding improved immunogenicity. Few data on influenza vaccine in premature infants are available, but infants with pulmonary disease may respond less robustly than others. Bacille Calmette Guérin vaccine appears to be most immunogenic if delayed until at least 34-35 weeks' postmenstrual age in very premature infants, although there may be non-specific advantages to its earlier administration. Premature infants may have persistently lower antibody titers than full-term infants, even years after initial immunization. Sick premature infants experience increased episodes of apnea or cardiorespiratory compromise following vaccine administration, necessitating careful monitoring. Specific factors that impair immune response, quality of the immune response, and safety and immunogenicity evaluation of new vaccines in premature infants are topics needing further research. Premature infants are at significant risk for decisions from healthcare providers that delay beginning and completing their vaccine regimens. A major challenge facing those who care for these infants is the provision of timely immunization.

Adverse Events After Routine Immunization of Extremely Low-Birth-Weight Infants

“…Premature infants have an altered immune response to immunization. 10 In one of the first studies in neonates that examined the effects of sepsis on subsequent production of antibodies following immunization, very low birth weight (<1500 g) infants with a history of bacteremia showed an alteration of immune response to specific serotypes of the pneumococcal vaccine. 11 Others have shown that prior history of sepsis in ELBW infants was actually protective against future episodes of late onset sepsis, 12 with one preclinical study suggesting a more robust innate immune response in immature mice.…”

Mother-Infant Transfer of Anti-Human Papillomavirus (HPV) Antibodies following Vaccination with the Quadrivalent HPV (Type 6/11/16/18) Virus-Like Particle Vaccine

“…This immature immune system is not fully capable of actively protecting against vaccinepreventable infections such as diphtheria, HPV infection, tetanus, and pertussis (9,20,30). Maternal immunoglobulins are transported across placental membranes during pregnancy by an active, receptor-mediated process.…”

Meningococcal disease: The advances and challenges of meningococcal disease prevention

“…In addition, immunogenicity and reactogenicity in this population can be complicated by many factors, including concurrent illness and postnatal administration of corticosteroids, which can suppress the immune response following vaccination. 85 Data on meningococcal vaccines in preterm infants are limited. The meningococcal group C conjugate vaccine has been shown to be immunogenic in preterm infants (32 weeks of age) when given alone or concurrently with other vaccines.…”