Association of Self-Reported COVID-19 Vaccination Status with COVID-19 Infection among Adult Long-Term Hematopoietic Cell Transplantation Survivors.

Hematopoietic cell transplantation (HCT) recipients experience significant morbidity and mortality from coronavirus disease 19 (COVID-19) infection. Data are limited regarding long-term HCT survivors' uptake of and experiences with COVID-19 vaccination and infection. This study aimed to characterize COVID-19 vaccination uptake, use of other prevention measures, and COVID-19 infection outcomes in adult HCT recipients at our institution. Between July 1, 2021, and June 30, 2022, long-term adult HCT survivors were surveyed regarding overall health, chronic graft-versus-host (cGVHD) status, and experiences with COVID-19 vaccinations, prevention measures, and infections. Patients reported COVID-19 vaccination status, vaccine-related adverse effects, use of nonpharmaceutical prevention measures, and infections. Comparisons by response and vaccination status were performed using the chi-square test and Fisher exact test for categorical variables and the Kruskal-Wallis test for continuous variables. Of 4758 adult HCT survivors who underwent HCT between 1971 and 2021 and consented to participate in annual surveys, 1719 (36%) completed the COVID-19 module, and 1598 of 1705 (94%) reported receiving ≥1 dose of COVID-19 vaccine. Severe vaccine-related adverse effects were infrequent (5%). Among respondents receiving an mRNA vaccine, completion of doses according to the Centers for Disease Control and Prevention's vaccine recommendations at the time of survey return was 2 doses in 675 of 759 (89%), 3 doses in 610 of 778 (78%), and 4 doses in 26 of 55 (47%). Two hundred fifty respondents (15%) reported COVID-19 infection; 25 (10%) required hospitalization. Vaccinated respondents reported significantly higher uptake of household vaccination (1284 of 1404 [91%] versus 18 of 88 [20%]; P < .001) and the use of nonpharmaceutical interventions (P < .001). Vaccinated respondents were significantly less likely to have contracted COVID-19 (85 of 1480 [6%] versus 130 of 190 [68%]; P < .001), as were their household members (149 of 1451 [10%] versus 85 of 185 [46%]; P < .001). Receipt of additional COVID-19 vaccine doses beyond the first dose was associated with a reduced risk of COVID-19 infection (odds ratio, .63; 95% confidence interval, .47 to .85; P = .002). Vaccination was well tolerated and associated with a lower risk of COVID-19 infection among HCT survivors and their household contacts. Vaccination and booster doses should be encouraged as part of a multifaceted approach in this high-risk population.