SARS-CoV-2 vaccine response and rate of breakthrough infection in patients with hematological disorders

Piñana, José Luis; Rodríguez-Belenguer, Pablo; Navarro, David; Spanish Hematopoietic Stem Cell Transplantation and Cell Therapy Group (GETH-TC)

doi:http://dx.doi.org/10.1186/s13045-022-01275-7

SARS-CoV-2 vaccine response and rate of breakthrough infection in patients with hematological disorders

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Piñana JL, López-Corral L, Martino R, Vazquez L, Pérez A, Martin-Martin G, Gago B, et al. SARS-CoV-2 vaccine response and rate of breakthrough infection in patients with hematological disorders. SARS-CoV-2 vaccine response and rate of breakthrough infection in patients with hematological disorders. J Hematol Oncol. 2022 May 7; 15(1): 54. DOI: 10.1186/s13045-022-01275-7

Abstract

Background: the clinical efficacy of SARS-CoV-2 vaccines according to antibody response in immunosuppressed patients such as hematological patients has not yet been established. Patients and methods: a prospective multicenter registry-based cohort study conducted from December 2020 to December 2021 by the Spanish transplant and cell therapy group was used to analyze the relationship of antibody response at 3-6 weeks after full vaccination (2 doses) with breakthrough SARS-CoV-2 infection in 1394 patients with hematological disorders. Results: at a median follow-up of 165 days after complete immunization, 37 out of 1394 (2.6%) developed breakthrough SARS-CoV-2 infection at median of 77 days (range 7-195) after full vaccination. The incidence rate was 6.39 per 100 persons-year. Most patients were asymptomatic (19/37, 51.4%), whereas only 19% developed pneumonia. The mortality rate was 8%. Lack of detectable antibodies at 3-6 weeks after full vaccination was the only variable associated with breakthrough infection in multivariate logistic regression analysis (Odds Ratio 2.35, 95% confidence interval 1.2-4.6, p = 0.012). Median antibody titers were lower in cases than in non-cases [1.83 binding antibody units (BAU)/mL (range 0-4854.93) vs 730.81 BAU/mL (range 0-56,800), respectively (p = 0.007)]. We identified 250 BAU/mL as a cutoff above which incidence and severity of the infection were significantly lower. Conclusions: our study highlights the benefit of developing an antibody response in these highly immunosuppressed patients. Level of antibody titers at 3 to 6 weeks after 2-dose vaccination links with protection against both breakthrough infection and severe disease for non-Omicron SARS-CoV-2 variants.