Objective: To investigate whether the immune response to the different types of vaccines and infection against SARS-Cov-2 virus affects ovarian follicle and its function and to evaluate whether the ART process affects the immunity obtained from either SARS-Cov-2 vaccines or infection. Methods: This is a prospective cohort study, included 45 consecutive IVF patients visiting private university fertility center, either immune with vaccination, previous infection or control. Serum and follicular fluid were collected to analyze the titer of anti-SARS-Cov-2 immunoglobulin G(IgG) as well as concentration of estrogen and progesterone both on cycle day 2-3 and the day of trigger. Main outcomes were serum immunoglobulin change during IVF procedure, and follicular function of steroidogenesis in serum and follicular fluid. Results: Of 45 women included in this study, 23 were vaccinated with Pfizer-BioNTech mRNA SARS-Cov-2 vaccine, 7 were vaccinated with other types of vaccines including Moderna and cross-inoculated with AstraZeneca and Janssen/J&J vaccines, 10 patients were known PCR test-positive to COVID-19 and recovered from the infection more than two weeks without any upper respiratory symptoms. There was no difference between serum and follicular fluid titer of spike protein IgG for SARS-Cov-2. However, relatively lower titer of serum and follicular IgG was more frequently observed in Pfizer-BioNTech vaccine group(45%, 14.3%, 20%, 20%; Pfizer, other types of vaccine, COVID-19 positive, control) with no statistical significance(p=0.351). There was no difference between serum estrogen and progesterone on Cycle day 2-3 or the day of trigger as the hormones in follicular fluid. Conclusion: The study findings suggest that procedure of controlled ovarian hyperstimulation does not affect the titer of spike protein IgG for COVID 19. In addition, there was no significant difference in steroidogenesis between groups depending on the presence or absence of immunity and how the immunity was acquired.