Vaccines against SARS-CoV-2 have shown remarkable efficacy and thus constitute an important preventive option against COVID-19, especially in fragile patients. We aimed to systematically analyse the outcomes of patients with haematological malignancies who received vaccination and to identify specific groups with differences in outcomes. The primary end point was antibody response after full vaccination (two doses of mRNA or one dose of vector-based vaccines). We identified 49 studies comprising 11086 individuals. Overall risk of bias was low. The pooled response for haematological malignancies was 64% (95% confidence interval [CI], 59-69; I²=93%) vs 96% (95% CI, 92-97; I²=44%) for solid cancer and 98% (95% CI, 96-99; I²=55%) for healthy controls (P<0.001). Outcome was different across haematological malignancies (P<0.001). The pooled response was 50% (95% CI, 43-57; I²=84%) for chronic lymphocytic leukaemia, 76% (95% CI, 67-83; I²=92%) for multiple myeloma, 83% (95% CI, 69-91; I²=85%) for myeloproliferative neoplasms, 91% (95% CI, 82-96; I²=12%) for Hodgkin's lymphoma, and 58% (95% CI, 44-70; I²=84%) for aggressive and 61% (95% CI, 48-72; I²=85%) for indolent non-Hodgkin's lymphoma. The pooled response for allogeneic and autologous haematopoietic cell transplantation was 82% and 83%, respectively. Being in remission and prior COVID-19 showed significantly higher responses. Low pooled response was identified for active treatment (35%), anti-CD20 therapy ≤ 1 year (15%), Bruton kinase inhibition (23%), venetoclax (26%), ruxolitinib (42%), and chimeric antigen receptor T-cell therapy (42%). Studies on timing, value of boosters, and long-term efficacy are needed. This study is registered with PROSPERO (CRD42021279051).
- Adults
- Older adults
- Vaccine/vaccination
- Efficacy/effectiveness
- Safety
- COVID-19
