Comparison of immunogenicity for Sinovac-CoronaVac vaccine vs. natural infection during cancer treatment.

Objective: Efficacy of the COVID-19 vaccines in cancer patients, especially during their active treatment, are lacking. Most of the studies in the literature compared the immunity in cancer patients with a cross-sectional cohort or retrospectively. Our study investigated Sinovac-CoronaVac COVID-19 vaccine immunogenicity and compared it with natural COVID-19 disease in cancer patients during their cancer therapy.

Patients And Methods: A total of 111 patients with cancer and who are on active treatment were included in the study. This is a single-center study and was designed prospectively. Two group of patients were included in the study, natural disease and vaccinated group.

Results: A total of 111 patients were included in the study, 34 of whom had natural COVID-19 disease. Antibody levels following the first dose vaccine were 0.4 (0-1.9) U/ml while after the second dose of vaccine were 2.6 (1.0-7.25) U/ml. Immunogenicity levels were 82.4% in the natural disease group and 75.8% in the vaccinated group after the second shot of the vaccine. Immunogenicity rate was significantly higher in non-chemotherapy (receiving immunotehrapy/targeted therapy or biologic agent) group compared to chemotherapy drug (92.9% vs. 63.3%, p=0.004). There was a difference between the antibody levels following the first and second vaccination [median (IQR): 0.3 (0-1.0) and 3.3 (2.0-6.7), p=0.001, respectively].

Conclusions: The present study revealed that the Sinovac-CoronaVac vaccine showed an acceptable immunogenicity following two shots in cancer patients who were receiving active systemic therapy. On the other hand, natural disease immunogenicity was higher than vaccinated group.