The Effect of the COVID-19 Pandemic on Influenza Vaccine Uptake by Pregnant Women in the US
Author(s)
Xiaofan Liu, MPH, Maddalena Ferranna, PhD, John A Romley, PhD;
University of Southern California, Los Angeles, CA, USA
University of Southern California, Los Angeles, CA, USA
Presentation Documents
OBJECTIVES: Pregnant women are among the highest priority groups for influenza vaccination, yet there is increasing maternal vaccine hesitancy after the COVID-19 pandemic. This study evaluates how the COVID-19 pandemic has differently impacted influenza vaccine uptake by pregnant women compared to their pre-pregnant period from 2017-2018 to 2022-2023 flu seasons in the US.
METHODS: Using De-identified Optum® Clinformatics® DataMart, this retrospective claim study included women aged 15 to 49 who had a live birth between November 1, 2017, and October 31, 2023, with continuous enrollment for at least two years before pregnancy. Influenza vaccine coverage was calculated for the same cohort in each flu season before and during pregnancy. A multivariable logistic regression model was used to estimate the effect of pregnancy and the COVID-19 pandemic on maternal influenza vaccine uptake, controlling for the pre-pregnant influenza vaccine uptake to ensure comparability across years.
RESULTS: A total of 311,245 pregnant women were included across 6 influenza seasons. The maternal influenza vaccine rate increased from 41% to 49% between 2017-2018 and 2019-2020 flu season but fell to 36% by 2022-2023 flu season. The pre-pregnancy influenza vaccine rate only decreased by 3 percentage points post-pandemic. Before the COVID-19 pandemic, influenza vaccine uptake during pregnancy was 15 percentage points higher than pre-pregnancy for the same pregnant women (OR = 2.022, p-value < 0.001). However, this higher vaccination willingness during pregnancy declined to 4 percentage points in 2020-2021 and reversed to -1 percentage point by 2022-2023 flu season (OR = 0.438, p-value < 0.001).
CONCLUSIONS: The influenza vaccine uptake decreased among both pregnant and pre-pregnant women post-pandemic, but a more significant decline among pregnant women. Before the COVID-19 pandemic, pregnant women were more likely to vaccinate than pre-pregnancy, plausibly influenced by increased healthcare access and maternal altruism. However, this trend reversed post-pandemic due to increased maternal vaccine hesitancy.
METHODS: Using De-identified Optum® Clinformatics® DataMart, this retrospective claim study included women aged 15 to 49 who had a live birth between November 1, 2017, and October 31, 2023, with continuous enrollment for at least two years before pregnancy. Influenza vaccine coverage was calculated for the same cohort in each flu season before and during pregnancy. A multivariable logistic regression model was used to estimate the effect of pregnancy and the COVID-19 pandemic on maternal influenza vaccine uptake, controlling for the pre-pregnant influenza vaccine uptake to ensure comparability across years.
RESULTS: A total of 311,245 pregnant women were included across 6 influenza seasons. The maternal influenza vaccine rate increased from 41% to 49% between 2017-2018 and 2019-2020 flu season but fell to 36% by 2022-2023 flu season. The pre-pregnancy influenza vaccine rate only decreased by 3 percentage points post-pandemic. Before the COVID-19 pandemic, influenza vaccine uptake during pregnancy was 15 percentage points higher than pre-pregnancy for the same pregnant women (OR = 2.022, p-value < 0.001). However, this higher vaccination willingness during pregnancy declined to 4 percentage points in 2020-2021 and reversed to -1 percentage point by 2022-2023 flu season (OR = 0.438, p-value < 0.001).
CONCLUSIONS: The influenza vaccine uptake decreased among both pregnant and pre-pregnant women post-pandemic, but a more significant decline among pregnant women. Before the COVID-19 pandemic, pregnant women were more likely to vaccinate than pre-pregnancy, plausibly influenced by increased healthcare access and maternal altruism. However, this trend reversed post-pandemic due to increased maternal vaccine hesitancy.
Conference/Value in Health Info
2025-05, ISPOR 2025, Montréal, Quebec, CA
Value in Health, Volume 28, Issue S1
Code
SA15
Topic
Study Approaches
Disease
No Additional Disease & Conditions/Specialized Treatment Areas, SDC: Infectious Disease (non-vaccine), SDC: Pediatrics, SDC: Reproductive & Sexual Health, STA: Vaccines