Early Childhood Vaccination Status of Preterm Infants

Abstract

BACKGROUND: Preterm infants are at increased risk for vaccine-preventable infections and associated complications. Limited studies describe timely vaccination of these vulnerable infants. METHODS: This retrospective cohort study included Washington State infants with birth hospitalizations at an urban academic medical center between 2008 and 2013. Demographic, clinical, and visit data from electronic health records were linked to vaccine data from the Washington State Immunization Information System. Completion of the recommended 7vaccine series by 19 months of age was compared between preterm infants (born at ,37 weeks' gestation) and term/postterm infants (born at 37-43 weeks' gestation) by using Pearson's x 2 test and multivariable logistic regression. Secondary outcomes included 7vaccine series completion by 36 months of age and receipt of individual vaccines in the series. Rotavirus, hepatitis A, and influenza vaccination was also assessed. RESULTS: Of study infants (n = 10 367), 19.3% were born prematurely. Preterm infants had lower 7-vaccine series completion compared with term/postterm infants by 19 months (47.5% vs 54.0%; adjusted odds ratio 0.77 [95% confidence interval 0.65-0.90]) and 36 months (63.6% vs 71.3%; adjusted odds ratio 0.73 [95% confidence interval 0.61-0.87]). Early preterm (23-33 weeks' gestation) and late preterm (34-36 weeks' gestation) infants had a lower rate of 7-vaccine series completion compared with term/postterm infants. Full influenza vaccination coverage by 19 months also differed between groups (early preterm: 47.7%; late preterm: 41.5%; term/postterm: 44.7%; P = .02). CONCLUSIONS: Over half of preterm infants were undervaccinated at 19 months; one-third failed to catch up by 36 months. Strategies to improve vaccination of these high-risk infants are needed. WHAT'S KNOWN ON THIS SUBJECT: Preterm infants are at an increased risk for vaccine-preventable infections and associated complications. Earlier work reveals that they may also be at risk for undervaccination, yet studies in which timely receipt of all currently recommended vaccines is examined in this population are lacking. WHAT THIS STUDY ADDS: This study revealed that fewer preterm infants completed the recommended 7-vaccine series by 19 months of age compared with term/postterm infants. These high-risk infants continued to lag behind in vaccination coverage at 36 months of age.

Vaccination timeliness and completeness among preterm and low birthweight infants: a national cohort study

“…30 Hofstetter et al found preterm infants less likely to have completed all doses of the "7-vaccine series" by age the age of 19 months. 51 The finding that preterm infants have completed catch up at 24 months in Israel may be attributed to the organization of provision of vaccination and accessibility. Childhood vaccinations are provided free of charge at community-based maternal and child-health clinics country-wide.…”

Vaccination timeliness and associated factors among preterm infants at a tertiary hospital in Uganda

“…The fear of side effects following immunisation and misinformation especially about immunising a sick child were cited as reasons for untimely vaccination of preterm infants in our study. Concerns about harmful events following immunisation is a major contributor to vaccine hesitancy in both high and low-income countries [19, 22, 23, 25, 26, 49, 51]. As such, it is a key barrier to timely vaccination, reflecting a need to strengthen provision of accurate information to improve vaccine timeliness.…”

“…The only exception to this is hepatitis B vaccination in infants weighing less than 2,000g because of a documented reduced immune response [14, 15]. Despite evidence that vaccines are safe and produce and adequate immune response in preterm infants [10, 11, 15], several studies in developed countries have shown that preterm infants are immunised with significant delay and at times vaccinations may be incomplete especially for those with lower birth weights (<2,500g) [13, 16–19]. The delay in vaccinating preterm infants could be a reflection of vaccine hesitancy.…”

Hepatitis B Vaccination of Low Birth Weight Infants in Washington State

“…3 The U.S Advisory Committee on Immunization Practices (ACIP) recommends that all infants born weighing <2,000 g receive their first HepB vaccine dose at hospital discharge or 30 days of age. 4 Despite this recommendation, studies suggest that these infants may be at increased risk for HepB undervaccination, 5,6 although further investigation in this high-risk population is needed. This is also important as timely receipt of the HepB birth dose has been associated with on-time completion of the three-dose HepB series and other early childhood vaccines.…”