BACKGROUND

Patients with hematological malignancies are at greater risk of severe COVID-19 and have been prioritized for COVID-19 vaccination. A significant proportion of them have an impaired vaccine response, both due to the underlying disease and to the treatments.

METHODS

We conducted a prospective observational study to identify the specific risks of the outpatient population with hematological diseases.

RESULT

Between 22 December 2021 to 12 February 2022, we followed 338 patients of which 16.9% ( = 57) developed SARS-CoV-2 infection despite previous vaccination (94.7%). COVID-19 patients were more likely to have received immunotherapy (85.5% vs. 41%, < 10), and particularly anti-CD20 monoclonal antibodies (40% vs. 14.9%, < 10) and Bruton's tyrosine kinase inhibitors (BTKi) (7.3% vs. 0.7%, < 10). There was no significant difference in demographic characteristics or hematological malignancies between COVID-19-positive and non-positive patients. Patients hospitalized for COVID-19 had more frequently received immunotherapy than patients with asymptomatic or benign forms (100% vs. 77.3%, < 0.05). Hospitalized COVID-19 patients had a higher proportion of negative or weakly positive serologies than non-hospitalized patients (92.3% vs. 61%, < 0.05). Patients who received tixagevimab/cilgavimab prophylaxis ( = 102) were less likely to be COVID-19-positive (4.9 vs. 22%, < 0.05) without significant difference in hospitalization rates.

CONCLUSION

In the immunocompromised population of patients with hematological malignancies, the underlying treatment of blood cancer by immunotherapy appears to be a risk factor for SARS-CoV-2 infection and for developing a severe form.