Safety of COVID-19 vaccination in patients with breast cancer (Preprint)

BACKGROUND `The widespread vaccination of the novel coronavirus vaccine (COVID-19 vaccine) has become one of the most likely effective means to end the COVID-19 pandemic. Tumor patients with high risk of infection, high incidence of serious events and high mortality should be the focus of epidemic prevention and treatment in the setting of COVID-19. But real-world data on the safety of vaccination for breast cancer patients are still unknown. OBJECTIVE This study aims to further analyze the safety of COVID-19 vaccine in vaccinated breast cancer patients. METHODS In the CSCO BC NCP-02 study, breast cancer patients who seek medical advice from October 2021 to December 2021were screened, from whom the vaccinated patients were enrolled in order to analysis the safety of vaccination. RESULTS The CSCO BC NCP-02 study screened 5766 patients who received COVID-19 vaccine, 45.1% (2599/5766) of the population were vaccinated before diagnosis of breast cancer, 41.3% (2379/5766) of the population were vaccinated after diagnosis of breast cancer, and the time of vaccination or diagnosis in 13.6% (784/5766) of the patients was unknown. Among breast cancer patients, 85.4% (2032/2379) were vaccinated one year after breast cancer diagnosis, and 95.4% (2270/2379) were vaccinated in the early breast cancer stage. Of all patients, 93.9% (5415/5766) received inactivated vaccine, 3.7% received recombinant subunit vaccine, 2.4% received other vaccines, including adenovirus and mRNA vaccine. In the first dose, the highest incidence of AE was 24.4% (95%CI, 11.2-37.5) for these received adenovirus vaccine. The lowest was 12.5% (95%CI: 11.6-13.4) for these received inactivated vaccines. In the second dose, both inactivated vaccines (8.7%, 95%CI:8.0-9.5) and recombinant vaccine (8.7%, 95%CI:5.5-12.0) showed the same incidence of AEs. Patients with metastatic breast cancer had the highest incidence of AEs (16.5%, 95%CI:9.5-23.5) at the first dose. The total incidence of AE vaccinated before and after diagnosis of breast cancer was 16.4% and 16.9%, respectively. The most common AEs were local pain (11.1% vs 9.1%), fatigue (5.5% vs 6.3%) and muscle soreness (2.3% vs 3.6%). The type of vaccines (OR=0.937,95% CI：0.689-1.273) and time window of vaccination (OR=0.919,95% CI：0.785-1.077) did not affect the incidence of AEs. CONCLUSIONS Compared with the patients vaccinated before diagnosis of breast cancer, the incidence of AEs of COVID-19 vaccine in breast cancer patients was not significantly increased. It is safe for these breast cancer patients to receive COVID-19 vaccines. CLINICALTRIAL ChiCTR2200055509