Characteristics of patients with hematologic malignancies without seroconversion post-COVID19 third vaccine dosing (3V): Real-world data from large midwestern healthcare system

ABSTRACT

Background: Patients (Pts) with hematologic malignancies (HM) are at greater risk of severe morbidity and mortality caused by COVID19 and show a lower response to the two-dose COVID19 mRNA vaccine series. The primary vaccine series now includes a third dose of the COVID19 vaccine (3V) for immunocompromised Pts. The objective of this study was to explore the characteristics of HM patients who had no change in SARS-CoV-2 spike protein titer levels post 3V (-/-) to gain a better understanding of the drivers of serostatus. Methods: This retrospective cohort study analyzed Pt data on SARS-CoV-2 spike IgG antibody titers pre- and post- 3V across the healthcare system. This study included 268 fully vaccinated HM Pts diagnosed with HM between October 31, 2019 and January 31, 2022 and had a negative serostatus prior to 3V. Post 3V titers were obtained 21 days after 3V. Demographics, association between characteristics and seroconversion status, and odds ratios were all assessed (table). Results: Pts with Non-Hodgkin lymphoma (NHL) had 6 times the odds of not seroconverting compared to multiple myeloma (MM) (CI 1.88 - 19.12, P = .0010). NHL also have about 14 times the odds of not seroconverting compared to Pts diagnosed with other HM conditions, which included neoplasms of uncertain behavior and disorders of white blood cells (CI 1.72 - 112.44, P = .0021). 90% of seronegative Pts showed no spike IgG antibody reaction to 3V as indicated by pre- and post- 3V index values. Demographics, previous COVID19 infection, and vaccine type were not significantly associated with seroconversion. Conclusions: HM patients who are not seroconverting after 3V, suggest a prioritized population for continued increased behavioral precautions, additional vaccination efforts, including a fourth dose of an mRNA COVID19 vaccine, as well as passive immunity boosting through monoclonal and polyclonal antibodies.