Presenting Author: E. Bridget Kim, PharmD, BCPS, BCOP, Massachusetts General Hospital, Boston, MA
Co-Authors: Jack Malespini, PharmD, BCOP, Victoria Yeung, Brenna Rowen, PharmD, BCOP, and Jennifer A. Hutchinson, PharmD, BCOP, Massachusetts General Hospital, Boston, MA
BACKGROUND: Patients with multiple myeloma and other plasma cell dyscrasias (PCD) are especially susceptible to infections, including influenza (flu). Multiple risk factors arise from disease-related immunoparesis, alteration in T-cell immunity, treatment-related immunosuppression, diminished protection from flu vaccines, and age-related decline in immune function. After the standard flu vaccine, these patients have shown to have low hemagglutination antibody inhibition titers, with decreased seroprotection rates of <20%. A booster dose could enhance immune efficacy. At Massachusetts General Hospital, we began implementing a 2-dose tandem flu vaccination strategy in patients with PCD in January 2021. Although it was previously reported that tandem flu vaccines can improve seroprotection rates, it has not yet been linked to better clinical outcomes.
OBJECTIVE: To compare flu-related clinical outcomes in patients with PCD who received 1 versus 2 flu vaccine doses.
METHODS: This study was a retrospective review of patients with PCD who received ≥1 flu vaccine over the past 4 flu seasons in 2020 to 2024. The primary outcomes were documented flu infections, level of clinical care required, and duration of hospitalization/PCD treatment interruptions. Secondary outcomes included flu treatment and time from most recent vaccine to flu infection.
RESULTS: A total of 100 randomly selected patients with PCD were included. The majority of patients had multiple myeloma (80%), and other PCDs included monoclonal gammopathy of undetermined significance, AL amyloidosis, and Waldenstrom macroglobulinemia. We identified 58 cases of documented flu infections (6 confirmed; 52 possible). In comparing flu rates, 84% of the flu cases occurred in patients who received 1 dose versus 16% in patients who received 2 doses of flu vaccine. The level of care required included phone call to the office (57% vs 5%), office visit (19% vs 7%), urgent care visit (7% vs 2%), and hospitalization (2%, 30-day vs 2%, 10-day) in the 1-dose versus 2-dose cohorts, respectively. PCD treatment interruption was required in 21% in the 1-dose cohort versus 2% in the 2-dose cohort. The mean duration of treatment interruption was 12 days (range, 1-30) and 10 days (range, not applicable; 1 instance) in 1-dose versus 2-dose cohorts, respectively. Oseltamivir was prescribed in 3.4% in the 1-dose cohort versus 1.7% in the 2-dose cohort. The time of flu from most recent vaccine was longer in the 1-dose cohort, with 237 days (range, 34-583), compared with 141 days (range, 52-420) in the 2-dose cohort.
CONCLUSIONS: The 2-dose tandem flu vaccines improve seroprotection and directly result in favorable flu-related clinical outcomes in patients with PCD. Other benefits include lower utilization of healthcare resources, decreased hospital stay, and decreased incidents of PCD treatment interruptions.
- Branagan AR, Duffy E, Albrecht RA, et al. Clinical and serologic responses after a two-dose series of high-dose influenza vaccine in plasma cell disorders: a prospective, single-arm trial. Clin Lymphoma Myeloma Leuk. 2017;17:296-304.
- Branagan A, Duffy E, Foster C, et al. Two dose series of high-dose influenza vaccine is associated with longer duration of serologic immunity in patients with plasma cell disorders. Blood. 2017;130(suppl 1):438.