Vaccines to prevent SARS-CoV-2 infection are considered the most promising approach to control the Covid-19 pandemic. Still, studies on the relationship between vaccination against Covid-19 and cancer have focused mostly on induced immunity rather than the disease itself. Considering that breast cancer is the most common cancer among women, the main objective of this study was to investigate the effect of Sinopharm and AstraZeneca vaccination on tumor characteristics (tumor size, important tumor markers, TILs, and metastasis to vital organs) of the luminal B (MC4L2) mouse model. Every two days, the mice's tumor size was measured and monitored. After thirty days, the mice were euthanized, and the presence of TILs, expression of important markers at the tumor site, and metastasis to vital organs were examined by H&E and IHC. Remarkably, all vaccinated mice had a reduction in tumor size, and there were more tumor-infiltrating lymphocytes in the tumor following immunization. Vaccinated mice had lower levels of tumor markers (VEGF, Ki-67, MMP-2/9), CD4/CD8 ratio, metastasis to vital organs, and decreased hormone receptors (ER, PR, and HER-2). Our findings demonstrated that COVID-19 vaccination can induce anti-cancer impact by reducing tumor progression and metastasis.