Problem:The COVID-19 pandemic has many clinical manifestations. Rapid vaccine development raised concerns and speculations about future fertility outcomes and vaccine safety. We evaluated the effect of Pfizer-BioNTech mRNA SARS-CoV-2 vaccine on IVF treatment, oocyte and embryo quality, and pregnancy outcomes. Method of study:This prospective, observational cohort study was conducted in a referral IVF Unit, 3/2021-5/2021. We aimed to recruit all women undergoing IVF/ICSI cycles from 3/1-4/30/2021, 2-8 weeks after the second vaccination, and to analyze 50-60 samples in the 2-month period. Patients were categorized according to serum antibody levels: positive for spike (S), positive for nucleotide (N), or negative for both.On the day of ovum pick-up, follicular fluid and blood samples were analyzed for antinucleotide (anti-N) antibodies, and anti-spike (anti-S) antibodies, hormonal profile, Creactive protein (CRP) and other metabolic parameters.Results: Of 59 women enrolled, 37 reported being vaccinated and 22 were not. We found 97% correlation between anti-S and anti-N in the blood and the follicular fluid.Follicular fluid was analyzed based on antibody categorization. All IVF treatment parameters in the follicular fluids and serum were comparable, except CRP was significantly elevated among patients with anti-N antibodies (2.