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

This is the first study that I've seen that credibly demonstrates a potentially significant adverse risk for vaccinations. It's confined to a small subset of the population, but one that is highly vulnerable - extremely low-birth weight infants. I personally suspect that babies who are born significantly early are special cases when it comes to vaccinations because many of their internal physical systems are not fully developed and functioning, and it could very well be that vaccinations should be delayed for them until they reach what would've been the age they would have received them had they been born counting from full-term. It's a risky proposition either way because they are at increased risk by delaying immunizations and hopefully the greater risk, vaccination vs non-vaccination, would be accurately calculated and influence the parents' decision.

What this study does NOT mean is that vaccinations are dangerous for the rest of the population. Most of us have fully-functioning immune systems that respond appropriately to vaccines, and to decrease vaccine administration would cause far more harm.

Adverse Events After Routine Immunization of Extremely Low-Birth-Weight Infants
Stephen D. DeMeo, DO1; Sudha R. Raman, PhD2; Christoph P. Hornik, MD, MPH1,2; Catherine C. Wilson, DNP, NNP-BC, FNP-BC3; Reese Clark, MD4; P. Brian Smith, MD, MPH, MHS1,2
[+] Author Affiliations
JAMA Pediatr. Published online June 01, 2015.

Importance Immunization of extremely low-birth-weight (ELBW) infants in the neonatal intensive care unit (NICU) is associated with adverse events, including fever and apnea or bradycardia, in the immediate postimmunization period. These adverse events present a diagnostic dilemma for physicians, leading to the potential for immunization delay and sepsis evaluations.

Objective To compare the incidence of sepsis evaluations, need for increased respiratory support, intubation, seizures, and death among immunized ELBW infants in the 3 days before and after immunization.

Design, Setting, and Participants In this multicenter retrospective cohort study, we studied 13 926 ELBW infants born at 28 weeks’ gestation or less who were discharged from January 1, 2007, through December 31, 2012, from 348 NICUs managed by the Pediatrix Medical Group.

Results Most of the 13 926 infants (91.2%) received 3 or more immunizations. The incidence of sepsis evaluations increased from 5.4 per 1000 patient-days in the preimmunization period to 19.3 per 1000 patient-days in the postimmunization period (adjusted rate ratio [ARR], 3.7; 95% CI, 3.2-4.4). The need for increased respiratory support increased from 6.6 per 1000 patient-days in the preimmunization period to 14.0 per 1000 patient-days in the postimmunization period (ARR, 2.1; 95% CI, 1.9-2.5), and intubation increased from 2.0 per 1000 patient-days to 3.6 per 1000 patient-days (ARR, 1.7; 95% CI, 1.3-2.2). The postimmunization incidence of adverse events was similar across immunization types, including combination vaccines when compared with single-dose vaccines. Infants who were born at 23 to 24 weeks’ gestation had a higher risk of sepsis evaluation and intubation after immunization. A prior history of sepsis was associated with higher risk of sepsis evaluation after immunization.

Conclusions and Relevance All ELBW infants in the NICU had an increased incidence of sepsis evaluations and increased respiratory support and intubation after routine immunization. Our findings provide no evidence to suggest that physicians should not use combination vaccines in ELBW infants. Further studies are needed to determine whether timing or spacing of immunization administrations confers risk for the developing adverse events and whether a prior history of sepsis confers risk for an altered immune response in ELBW infants.