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Identifying infants at increased risk for late initiation of immunizations: maternal and provider characteristics
Kristen A Feemster1, C Victor Spain, Michael Eberhart
1The Robert Wood Johnson Clinical Scholars Program, University of Pennsylvania School of Medicine, Philadelphia, PA, USA. feemster@email.chop.edu
Insights
Maternal factors like younger age and fewer prenatal visits predict delayed infant immunizations. Public health clinics also showed higher rates of late vaccine starters, indicating a need for early intervention.
Area of Science:
- Pediatrics
- Public Health
- Epidemiology
Background:
- Timely infant immunizations are crucial for disease prevention.
- Late initiation of vaccines can lead to increased susceptibility to infectious diseases.
- Identifying predictors of delayed vaccination is essential for targeted public health interventions.
Purpose of the Study:
- To identify maternal, provider, and community factors associated with late initiation of infant immunizations.
- To determine predictors for infants starting office-based immunizations after 90 days of age.
Main Methods:
- Retrospective cohort study of infants born in Philadelphia between 2002 and 2004.
- Analysis of immunization registry data for 54,429 infants.
- Hierarchical logistic regression and Cox regression models to identify predictors of late vaccination initiation.
Main Results:
- 12.6% of infants were identified as late starters.
- Maternal factors including younger age, fewer than five prenatal visits, lower education, higher birth order, and smoking were associated with delayed immunization.
- Receiving care at hospital/university-based or public health clinics was also linked to higher rates of late starters.
Conclusions:
- Younger maternal age, fewer prenatal visits, higher birth order, and public health clinic care are strong predictors of delayed infant immunization.
- Risk factor profiles using readily available birth data can identify high-risk infants.
- Early interventions and collaboration with prenatal care providers are recommended to improve immunization rates.
Objective:
We identified maternal, provider, and community predictors among infants for late initiation of immunizations.
Methods:
We performed a retrospective cohort study of infants born between January 1, 2002, and December 31, 2004, in Philadelphia, Pennsylvania. Primary outcomes were age in days at first office-based immunization and status as a late starter (i.e., initiating office-based immunizations after 90 days of age). Candidate predictors included sociodemographic and prenatal characteristics, immunization provider practice type and size, and neighborhood factors. We performed hierarchical logistic regression and Cox regression models to identify independent predictors for being a late starter and prolonged time to first immunization.
Results:
Of the 65,519 infants from this birth cohort in Philadelphia's immunization registry, 54,429 (88.1%) were included in analysis and 12.6% of these were late starters. Infants whose mothers were younger, received less than five prenatal visits, had less than a high school education, had more than two children, and who smoked cigarettes prenatally were significantly more likely to be late starters. Receiving care at hospital/university-based or public health clinics was also significantly associated with likelihood of being a late starter. Neither distance between infant's residence and practice nor neighborhood socioeconomic indicators was independently associated with the outcomes. Common risk factor profiles based on practice type and four maternal characteristics were found to reliably identify infant risk.
Conclusions:
Maternal receipt of fewer prenatal care visits, younger maternal age, higher birth order, and receiving care at public health clinics were the strongest predictors of being a late starter and time to first immunization. Risk factor profiles based on information already collected at birth can be used to identify higher-risk infants. Early intervention and potentially partnering with prenatal care providers may be key strategies for preventing underimmunization.
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