What Is the Role of COVID-19 Monoclonal Antibody Programs in Promoting Posttreatment Vaccination?

Background: In addition to highly efficacious mRNA vaccines, there are multiple therapeutic tools to prevent COVID-19, reduce the severity of illness, and prevent death among high-risk patients. Monoclonal antibodies (mAb) are vital to prevent and to manage acute illness, but subsequent vaccination is essential to mitigate risk of reinfection. The objective of our study was to assess vaccination status after mAb treatment. Methods: We conducted a retrospective, observational cohort study of high-risk adults who were treated with bamlanivimab for mild-moderate COVID-19 between December 2020 and March 2021 at an ambulatory infusion center or 3 emergency departments in the Bronx, NY. Demographics, mAb treatment information, and vaccination status as of February 28, 2022, were collected from the electronic medical record. Patient outreach phone calls were made to obtain information missing in the electronic medical record. Results: A total of 722 adults were included. Forty patients (6%) were vaccinated before mAb treatment. Of patients who were unvaccinated at time of treatment (n = 682), 569 (83%) were subsequently vaccinated, 35 (5%) remained unvaccinated, and 78 (11%) had an unknown vaccination status as of March 2022. The mean age of vaccinated patients was 59 years and unvaccinated patients was 54 years (P = 0.05). Median time to vaccination was 99 days (interquartile range, 90-142 days). As of March 2022, 307 patients (43%) had received at least 1 vaccine booster dose. Conclusions: Most patients who were unvaccinated at time of treatment were subsequently vaccinated. Ambulatory COVID-19 encounters are valuable opportunities to provide vaccine education and counseling.