Factors Associated with Influenza & Tdap Vaccine Uptake in Pregnant Patients at the UT Family Medicine Clinic in Memphis
Authors: Woods Rachel , Zhong Alison , Vincent Madelyn 
Published: October 2021

INTRODUCTION: Given the increased risk for infections among pregnant patients and newborns, vaccination against influenza (>50,000,000 annual US cases affecting all ages) and pertussis (>15,000 annual US cases disproportionately affecting newborns) are recommended among pregnant patients in order to protect them and their babies via passive immunity to cover a newborn’s window of vaccine ineligibility. Though flu and Tdap vaccination rates among pregnant patients have been trending upwards nationally, there is still room for improvement to achieve optimal rates. OBJECTIVES: The primary objectives were to study factors that affect the vaccination rates at the University of Tennessee Family Medicine Clinic at Memphis (UTFMC-M), compare those rates with national pregnancy flu/Tdap vaccination rates, and to generate recommendations based off observed factors associated with vaccine uptake to improve flu/Tdap vaccination rates in UTFMC-M pregnant patients. METHODS: This was a retrospective chart review of UTFMC-M patients who were pregnant from September 1, 2019-April 24, 2020 (included 2019-2020 flu season) (n=465). Variables studied included demographic data (race, age, insurance), immunization history (vaccine status, history of physician encouragement), and prenatal history (parity, number of prenatal visits, trimester at first visit, high risk clinic (HRC) admittance status). Vaccination status was based on ACIP recommendations (Flu shot eligible = any gestational age; Tdap eligible = ≥27 weeks). Positive HRC admittance was noted for patients with ≥2 visits to the UTFMC-M HRC, a clinic that specializes in high risk pregnant patient care. RESULTS: The patient sample was predominantly black (84.3%) and insured by Medicaid programs (88%). Among eligible UTFMC-M pregnant patients, 50.1% were flu-vaccinated (n=465); 73.8% were Tdap-vaccinated (n=317); and 52.1% were Flu+Tdap-vaccinated (n=317). No significant associations were found between vaccine uptake and HRC status, parity, and age. However, statistically significant relationships were found between vaccine uptake and physician encouragement (positive relationship with flu shot: X2(1, N = 465) =131, p < 0.001, Tdap: X2 (6, N = 465) =476, p < 0.001), number of prenatal visits (flu shot group median 8 visits, Tdap group median 9 visits vs. unvaccinated group median 4 visits; p < 0.001), and early trimester age at first prenatal visit (X2(6, N = 465) =47.635 , p CONCLUSION: 2019-2020 UTFMC-M vaccination rates were on par with 2018-2019 US flu vaccine rates and higher than 2018-2019 US Tdap and Flu+Tdap rates. There were statistically significant relationships between vaccine uptake at UTFMC-M and physician encouragement, number of prenatal visits, and early trimester age at first prenatal visit but no significant relationships with UTFMC-M HRC admittance, parity, or age. Recommendations following from our observations to address further vaccine rate improvement include: continue vaccine encouragement, continue booking multiple visits (8 for flu, 9 for Tdap), prioritize Tdap vaccine higher for late trimester intake patients, and focus on flu vaccine encouragement and education.