Abstract
Data on the effectiveness and safety of approved SARS-CoV-2 vaccines in cancer patients are limited. This observational, prospective cohort study investigated the humoral immune response to SARS-CoV-2 vaccination in 232 cancer patients from 12 HeCOG-affiliated oncology departments compared to 100 healthcare volunteers without known active cancer. The seropositivity rate was measured 2-4 weeks after two vaccine doses, by evaluating neutralising antibodies against the SARS-CoV-2 spike protein using a commercially available immunoassay. Seropositivity was defined as ≥33.8 Binding-Antibody-Units (BAU)/mL. A total of 189 patients and 99 controls were eligible for this analysis. Among patients, 171 (90.5%) were seropositive after two vaccine doses, compared to 98% of controls (p = 0.015). Most seronegative patients were males (66.7%), >70-years-old (55.5%), with comorbidities (61.1%), and on active treatment (88.9%). The median antibody titers among patients were significantly lower than those of the controls (523 vs. 2050 BAU/mL; p < 0.001). The rate of protective titers was 54.5% in patients vs. 97% in controls (p < 0.001). Seropositivity rates and IgG titers in controls did not differ for any studied factor. In cancer patients, higher antibody titers were observed in never-smokers (p = 0.006), women (p = 0.022), <50-year-olds (p = 0.004), PS 0 (p = 0.029), and in breast or ovarian vs. other cancers. Adverse events were comparable to registration trials. In this cohort study, although the seropositivity rate after two vaccine doses in cancer patients seemed satisfactory, their antibody titers were significantly lower than in controls. Monitoring of responses and further elucidation of the clinical factors that affect immunity could guide adaptations of vaccine strategies for vulnerable subgroups.
Highlights
Cancer patients are at increased risk of severe Coronavirus disease 2019 (COVID-19) disease and have significantly higher mortality rates and are, highly prioritized for vaccination against severe acute respiratory syndrome coronavirus 2 (SARSCoV-2) [1,2,3]
A total of 232 consecutive cancer patients vaccinated against SARS-CoV-2 with the BNT162b2 (Pfizer-BioNTech, Marburg, Germany), mRNA-1273 (Moderna Biotech, Madrid, Spain S.L.) or the AZD1222 (Astra Zeneca, Leiden, the Netherlands) vaccine, and 100 hospital-personnel volunteers without active cancer at the time of vaccination who received the BNT162b2 mRNA vaccine, were enrolled
Forty-three patients and one control did not meet the criteria for the current analysis, and were excluded, leading to a total of 189 cancer patients and 99 controls (Figure 1)
Summary
Cancer patients are at increased risk of severe Coronavirus disease 2019 (COVID-19) disease and have significantly higher mortality rates and are, highly prioritized for vaccination against severe acute respiratory syndrome coronavirus 2 (SARSCoV-2) [1,2,3]. Cancer patients are at increased risk of severe Coronavirus disease 2019 Observational clinical studies suggest lower influenza mortality and morbidity in cancer patients who have been vaccinated, suggesting an effective immune response [11,12], even when undergoing systemic chemotherapy [13]. Based on extrapolation from other vaccines, the efficacy and safety of vaccination against SARS-CoV-2 in cancer patients may be similar to that in patients without cancer, it may be generally lower in certain severely immunosuppressed subgroups. Two vaccine trials have enrolled cancer patients, but in very small numbers: 4% cancer patients were enrolled in the Pfizer vaccine trial, and only 0.5% in the Janssen vaccine trial Even these patients were not analysed separately to provide information on the safety and efficacy of the vaccines [14,15,16]. A lower response to vaccination was observed in solid organ transplant recipients and, more recently, in patients with hematologic malignancies [17,18,19]
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