Trans-Placental Transfer and Vertical Transmission of SARS-CoV-2, HIV and HCV: A Comparative Review

Background: Although SARS-CoV-2 infection has spread fast throughout the world, information on the natural history of illness in pregnant women and the risk of mother-to-fetal transmission is limited. HIV and HCV also showed evidence of mother-to-fetal transmission. Aim: Reviewing literature reports and published data regarding possibility of viral transmission to fetus, and to what extend it could occur for SARS-CoV-2, HIV, and HCV. Discussion: According to certain research, there is no viremia detected in maternal or cord blood, and there is no indication of vertical SARS-CoV-2transmission. Infection can be transmitted transplacentally during the last pregnancy weeks. The absence of placental infection is supported by the finding that the SARS-CoV-2 receptor, the Angiotensin 2 Converting Enzyme (ACE2) required for cell integration, is only present at extremely low amounts in the placenta during the first third trimester. Studies indicated that HIV vertical transmission rates during pregnancy, birth, or breastfeeding range from 13% to 48%, but researches indicated that 90% of the babies protected against HIV during pregnancy. HCV-infected pregnant women have a 2% to 8% risk of viral transmission, but the presence of NK cells in the placentas of HCV-positive women contribute for protective effect. Conclusion: The possibility of Trans-placental transmission of SARS-CoV-2, HIV, and HCV is possible with different incidence rates.