COVID-19 and Influenza fl uenza Vaccine Coadministration Among Older US Adults

Introduction: Coadministering COVID-19 and influenza fl uenza vaccines is recommended by public health authorities and intended to improve uptake and convenience; however, the extent of vaccine coadministration is largely unknown. Investigations into COVID-19 and influenza fl uenza vaccine coadministration are needed to describe compliance with newer recommendations and to identify potential gaps in the implementation of coadministration. Methods: A descriptive, repeated cross-sectional study between September 1, 2021 to November 30, 2021 (Period 1) and September 1, 2022 to November 30, 2022 (Period 2) was conducted. This study included community-dwelling Medicare beneficiaries fi ciaries >= 66 years who received an mRNA COVID-19 booster vaccine in Periods 1 and 2. The outcome was an influenza fl uenza vaccine administered on the same day as the COVID-19 vaccine. Adjusted ORs and 99% CIs were estimated using logistic regression to describe the association between beneficiaries' fi ciaries ' characteristics and vaccine coadministration. Statistical analysis was performed in 2023. Results: Among beneficiaries fi ciaries who received a COVID-19 vaccine, 78.8% in Period 1 (N=6,292,777) N =6,292,777) and 89.1% in Period 2 (N=4,757,501), N =4,757,501), received an influenza fl uenza vaccine at some point during the study period (i.e., before, after, or on the same day as their COVID-19 vaccine), though rates were lower in non-White and rural individuals. Vaccine coadministration increased from 11.1% to 36.5% between periods. Beneficiaries fi ciaries with dementia (aOR Period 2 =1.31; 99%CI=1.29-1.32) - 1.32) and in rural counties (aOR Period 2 =1.19; 99%CI=1.17-1.20) - 1.20) were more likely to receive coadministered vaccines, while those with cancer (aOR Period 2 =0.90; 99%CI=0.89-0.91) - 0.91) were less likely. Conclusions: Among Medicare beneficiaries fi ciaries vaccinated against COVID-19, influenza fl uenza vaccination was high, but coadministration of the 2 vaccines was low. Future work should explore which factors explain variation in the decision to receive coadministered vaccines. Am J Prev Med 2024;67(1):67-78. - 78. (c) 2024 The Authors. Published by Elsevier Inc. on behalf of American Journal of Preventive Medicine. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).