(988) Tetanus-diptheria-acellular pertussis (Tdap) vaccine receipt in pregnancy and its association with community-level socioeconomic vulnerability

To estimate the association between prenatal Tdap vaccine receipt and measures of community-level socioeconomic deprivation, as limitations of existing research preclude an accurate characterization of the relationship.

Study Design:

A retrospective cohort study of pregnant women who delivered at ≥ 28 weeks at a single tertiary care center between September 1, 2019 and November 30, 2022 for whom prenatal records were available.  The primary exposure was socioeconomic vulnerability as measured by the CDC’s Social Vulnerability Index (SVI). Patient addresses were geocoded and linked at the census tract level to assign their SVI values. SVI scores are composed of 15 variables organized into 4 themes: socioeconomic status, household composition/disability, minority status/language, and housing type/transportation. Scores range from 0-1; greater values indicate greater socioeconomic disadvantage. Automated data abstraction was used to obtain discrete variables from the medical record, including demographics and the primary outcome, Tdap vaccine receipt. The primary exposure was assessed as a continuous and categorical quartile variable. We used multivariable logistic regression to estimate the independent association between SVI and Tdap vaccine receipt.

Results:

Of 5190 pregnant women included, the rate of Tdap vaccine receipt was 57%. Women with higher SVI scores had lower odds of Tdap vaccination (aOR 0.51, 95%CI 0.42-0.62). Women in the highest quartile for SVI themes 3 and 4 had lower odds of Tdap vaccination (aOR 0.63, 95%CI 0.50-0.79, aOR 0.69, 95%CI 0.57-0.85, respectively) (Table). Non-English language and public insurance were also associated with lower odds of Tdap vaccine receipt.

Conclusion:

Pregnant women living in areas with greater socioeconomic disadvantage are less likely to receive the Tdap vaccine. Among SVI themes, racial/ethnic minority status and housing type/transportation appear to drive the inverse relationship between SVI and Tdap vaccine receipt. SVI may be used to identify barriers to prenatal vaccine receipt and thereby guide interventions that seek to enhance vaccine equity.