ABSTRACT
BACKGROUND: The new coronavirus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has produced a global pandemic of coronavirus disease 2019 (COVID-19), resulting in modifications to public health policies on a universal scale. SARS-CoV-2 vaccine has evolved as the most effective and secure way for protecting healthy individuals against COVID-19. Patients with cancer were excluded from clinical trials due to their increased COVID-19 risk and current immunosuppressing therapy. Safety and effectiveness evidence is insufficient for SARS-CoV-2 vaccination in cancer patients. AIM: To assess the efficacy and safety of two-dose SARS-CoV-2 vaccines in cancer patients. METHODS: A multicenter observational study was performed at ten Chinese hospitals between January 1, 2021 and December 31, 2021. Each participant in the research received two doses of vaccination. A total of 215 healthy people were screened and 132 eligible patients with cancer were recruited. In order to verify the safety of the second dose of the vaccine, a side-effect report was compiled. Two weeks following the second vaccination dose, subjects underwent an analogous questionnaire survey. Utilizing a magnetic particle-based chemiluminescence immunoassay, serum levels of anti-SARS-CoV-2 immunoglobulin G (IgG) antibodies were measured to determine the effectiveness of vaccination. IgG levels ≥ 10 AU/mL were considered seropositive. RESULTS: All the 347 eligible patients completed the follow-up, and anti-SARS-CoV-2 IgG antibodies were detected. Local pain at the injection location was the most common side effect mentioned by all responders, with an increased incidence in cancer patients than the healthy people after the second dose vaccine (17.2% vs 9.1%; P = 0.035). There was no significant difference in headache, urticaria, or other adverse reactions between patients with cancer and healthy people. In the group of cancer patients, the seropositivity incidence was 83.3%, while it was 96.3% in the group of healthy people. In the group of cancer patients, the seropositivity incidence and antibody levels were significantly lower (P < 0.001). This analysis showed a poorer response rate in patients on active immunosuppressive treatment and elderly cancer patients. CONCLUSION: Two-dose Chinese vaccines are effective and safe in cancer patients. However, further research is required on the efficacy in elderly cancer patients and those on active immunosuppressive treatment.