OBJECTIVES: The issue of suboptimal flu vaccine coverage during pregnancy has been previously addressed by studies conducted with internet panel survey and several active surveillance systems. However, most of them suffered from insufficient statistical comparison due to lacking complex probabilistic sampling design. Our study aimed to explore the determinants and coverage of influenza vaccination among pregnant women using a national representative sample of the United States.

METHODS: This study was conducted with the 2012-2015 National Health Interview Survey (NHIS). The Andersen Behavioral Model of Health Services Use was applied as the conceptual framework to explore potential factors that may influence the flu vaccination rate. A series of individual determinants, categorized into predisposing, enabling and need factors, were compared using logistic regressions between women who received flu shot before/during pregnancy and those who did not. All analyses were adjusted for complex survey designs and sample weights using SAS 9.4 (SAS Institute, Cary NC).

RESULTS: Among an estimated 4.8 million pregnant women, an average of 35% women received influenza vaccination before/during pregnancy. The odds of receiving a flu shot before/during pregnancy was lower among non-Caucasian ethnicity groups (odds ratio (OR) [95% confidence interval (CI)], African American, 0.777 [0.550-1.098]; others, 0.636 [0.429-0.942]), women without usual source of health care (OR, 0.647 [0.442-0.945]), and women with heavier alcohol consumption (OR, 0.601 [0.403-0.894]). In contrast, higher education and family income were positively correlated with influenza vaccination, with an OR of 1.763, [1.290-2.409] (>= bachelor’s degree versus <= high school) and 2.038 [1.368-3.035] (ratio of family income to the poverty threshold category >4 versus <1), respectively.

CONCLUSIONS: No usual source of health care, poverty, lower education level and alcohol drinking behavior appeared to be negatively associated with influenza vaccination during pregnancy. Policy makers may consider developing interventions to improve the vaccination rate among these subgroups.