Immune Response to Anti-Sars-cov-2 Prime-Vaccination in Patients with Cancer: a Systematic Review and Meta-Analysis

This systematic review and meta-analysis aimed to evaluate the immune response to anti-SARS-CoV-2 prime-vaccination in patients with cancer. We performed a systematic literature search using PubMed, Embase, and Cochrane Library until 28/09/2021, and conference proceedings from ASCO and ESMO 2021 annual meetings. We screened for observational or interventional studies including subjects ≥ 16 years old with cancer diagnosis who were vaccinated against SARS-CoV-2. Prime-vaccination was defined as one dose of Ad26.COV2-S vaccine or two doses of BNT162b2, mRNA-1273, ChAdOx1-S or inactivated SARS-CoV-2 vaccine. The outcomes were humoral and adaptive immune responses (proportion of subjects with positive titers of antibody anti-SARS-CoV-2 spike protein and anti-SARS-CoV-2 cellular responses, respectively). We included 89 records reporting data from 30,183 subjects. The overall seropositive rate within the first month after complete anti-SARS-CoV-2 prime-vaccination was 80% [95% confidence interval (CI), 72–86%], 60% (95%CI, 53–67%) in patients with hematological malignancies (HM) versus 94% (95%CI, 88–97%) in patients with solid malignancies (SM). The diagnosis of HM was significantly associated with a lower seropositive rate on multivariate meta-regression (odds ratio 0.35, 95% CI 0.18–0.69, HM versus both, p = 0.002). The overall humoral response was 49% (95% CI, 42–56%) after incomplete prime-vaccination and 79% (95% CI, 70–86%) at 2 months after complete prime-vaccination. These responses were also lower in patients with HM at these time points. The overall cellular response rate at any time after vaccination was 61% (95% CI, 44–76%). This meta-analysis provides compelling evidence of humoral and adaptive immune responses against SARS-CoV-2 in patients with cancer, which last for at least 2 months following complete prime-vaccination.