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SARS-CoV-2 Vaccine Response and Risk of Breakthrough Infection in Hematological Patients
27 Pages Posted: 21 Feb 2022
More...Abstract
Background: Clinical efficacy of SARS-CoV-2 vaccines according to the antibody response in immunossuppressed patients such as hematological patients has not been established yet.
Patients and Methods: Through a prospective multicenter registry conducted from December 2020 to Decembre 2021 by the Spanish transplant and cell therapy group, we analyzed the relationship of antibody response at 3-6 weeks after full vaccination (2 doses) and breakthrought SARS-CoV-2 infection in 1394 hematological patients.
Results: At a median follow-up of 165 days after complete immunization, 37 out of 1394 (2.6%) developed breakthrouth 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 of the patients were asymptomatic (19/37, 51.4%) whereas only 19% developed pneumonia. The mortality rate was 8%. The 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 not-cases [1.83 binding antibody units (BAU)/mL (range 0-4854.93) vs 730.81 BAU/mL (range 0-56800), respectively (P= 0.007)]. We identified 250 BAU/mL as a cut-off above which the incidence and the severity of the infection was significantly lower.
Conclusions: Our study highlights the benefit of mounting an antibody response in these highly immunossuppressed patients. The antibody titers at 3 to 6 weeks after complete 2-dose vaccination correlates with protection of both breakthrough infection and severe disease, emphasizing the need for serological testing-based decisions on further vaccine doses.
Funding Information: None.
Declaration of Interests: The author(s) declare that they have no conflict of interests.
Ethics Approval Statement: The local ethical committee of the Hospital Clínico Universitario of Valencia approved the registry and study protocol (reference code 35.21). The local ethical committee of the Hospital Clínico Universitario of Valencia approved the registry and study protocol (reference code 35.21).
Keywords: SARS-CoV-2 vaccines, breakthrough SARS-CoV-2 infection, correlates of protection, hematological malignancies, allogeneic stem cell transplantation, autologous stem cell transplantation, COVID-19, vaccine, immunocompromised patients, Moderna mRNA-1273, Pfiz
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