ABSTRACT
Background: SARS-CoV-2 vaccination in cancer patients is crucial to prevent severe COVID-19 disease course. Methods: This study assessed immunogenicity of cancer patients on active treatment receiving mRNA-based SARS-CoV-2 vaccine by detection of anti-SARS-CoV-2 S1 IgG antibodies in serum, before, after the first and second doses and 3 months after a complete primary course of vaccination. Results were compared with healthy controls. Results: Of 112 patients, the seroconversion rate was 96%. A significant reduction in antibody levels was observed 3 months after vaccination in patients receiving immune checkpoint inhibitors versus control participants (p < 0.001). Adverse events were mostly mild. Conclusion: Immunogenicity after mRNA-based vaccine in cancer patients is adequate but influenced by the type of anticancer therapy. Antibody levels decline after 3 months, and thus a third vaccination is warranted.
Because cancer patients are especially endangered by SARS-CoV-2 infection and have worse disease course and outcomes, it is crucial to protect them from this infection. This study was aimed at assessing protective antibodies after patients received mRNA-based SARS-CoV-2 vaccines. Protective antibodies (e.g., anti-SARS-CoV-2 S1 IgG antibodies) were assessed in patients' blood before vaccination, after the first and second doses and 3 months after a complete primary course vaccination. Patients' oncological treatment was unaffected by the vaccination received. The results of protective antibodies were also compared with healthy control subjects who were vaccinated in the same manner. More than 110 cancer patients participated and agreed to have their blood samples analyzed. The rate of antibody production was 96% after a complete primary course of vaccination and was similar with that of healthy control subjects. However, there were some differences noted regarding the oncological treatment that the patients were receiving, with patients who were treated with targeted therapy achieving the highest levels of protective antibodies. Adverse events after vaccination were mostly mild and did not interfere with patients' general performance. The rate of antibody production for cancer patients after SARS-CoV-2 vaccination is high and similar to that in healthy control subjects but varies with regard to the oncological treatment that patients are receiving. However, antibodies decline substantially after 3 months, and thus a third vaccination is desirable. There were no new safety concerns after vaccination, and most adverse events were mild and short-lived.