Hormonal and Histological Effects of the Inactivated SARS-CoV-2 (TURKOVAC™) Vaccine on Ovarian Reserve

Introduction: Many countries carried out mass vaccination campaigns during the coronavirus diseases 2019 pandemic.Almost all the data on the effects of vaccines used in these campaigns on ovarian reserve come from studies to investigate the effects of their use on assisted reproductive outcomes.This study was conducted to investigate the possible effects of the inactivated SARS-CoV-2 vaccine on the number of ovarian follicle forms and serum anti-mllerian hormone (AMH) levels in rats. Materials and Methods:A total of 20 female Wistar Albino rats, aged 16 to 20 weeks, were randomly assigned in a 1:1 ratio to either group 1 (control group) or group 2 (inactivated SARS-CoV-2 vaccine group).The control group was not treated.The vaccine group received two doses of the inactivated SARS-CoV-2 vaccine at 28-day intervals.On the 29 th day after receiving the second dose, blood samples were taken from the hearts of the rats under anesthesia.The rats were euthanized by cervical dislocation, followed by bilateral oophorectomy performed via laparotomy.Primordial, primary, secondary, antral, preovulatory, and atretic follicle forms were counted in ovarian tissue sections using light microscopy.Serum AMH levels were measured using ELISA. Results:The mean primordial and primary follicle numbers were decreased in the inactivated vaccine group compared to the control group (p< .001).However, the numbers of other follicle forms were similar in both groups.Serum AMH levels (ng/mL) were 9.9 (9.4-10.2) in the control group and 9.7 (9.1-10.0) in the inactivated vaccine group, and there was no difference in AMH levels between the groups (p= 0.481). Conclusion:Our findings suggest that the inactivated SARS-CoV-2 vaccine administered to rats may reduce the primordial follicle pool.Consequently, serum AMH levels and antral follicle numbers, which remain within the normal range, may not accurately reflect ovarian reserve.