Serological Response to COVID-19 Vaccination is Impaired in Adults with Hematologic Malignancies when Compared to Adults with Solid Tumors and HIV: Observations from a Single Tertiary Institution

Abstract

Background: Hematologic malignancies can impair immune responses following COVID-19 vaccination. We analyzed seroconversion rates following a primary two-dose COVID-19 vaccination series and subsequent seroconversion rates after booster doses (doses 3 and above) in patients with various subtypes of hematologic malignancies (HM), human immunodeficiency virus infection (HIV), and solid tumors (ST). Methods: We conducted a retrospective study of 299 fully vaccinated adults with HM (n=202), HIV without diagnosed cancer (n=48), HIV and cancer (n=17), ST (n=12), autoimmune diseases (n=12), or other hematologic diseases (n=10) seen in a single tertiary institution between May 2020 and July 2022. A serum spike antibody level ≥0.8U/mL was considered evidence of seroconversion as defined by the manufacturer (Roche Elecsys®). A Mann-Whitney test was utilized to analyze continuous variables and a chi-square test for categorical variables. Results: Seroconversion after initial vaccination was significantly associated with disease category and treatment. Seroconversion rates were lowest in people with B-cell lymphomas (including patients not currently receiving treatment) (44/68) and patients receiving anti-B-cell monoclonal antibodies (23/57). All individuals with HIV alone or ST (n=60) demonstrated seroconversion after initial vaccination as did 94% of individuals with HIV and cancer (16/17) and 86% of those with plasma cell dyscrasias (37/43). Of the 51 people who did not seroconvert after their primary vaccination course, 25 achieved seroconversions after one booster dose. Conclusion: Our study supports the potential utility of COVID-19 serological testing to identify those at high risk of impaired response to COVID-19 vaccination and to help physicians develop personalized vaccination strategies. Continued research is needed to refine our understanding of immune response in these patients and improve their protection against COVID-19. Keywords: COVID-19 Vaccination, Impaired Immune Response, Seroconversion, HIV, Hematologic Malignancies