The research is based on the study of 16 eggs from two asymptomatic women who underwent controlled ovarian stimulation and who had tested positive for SARS-CoV-2 infection by PCR on the day their eggs were extracted. After the women were found to be positive for Covid-19, it was agreed not to use their oocytes for reproductive purposes, in line with a precautionary principle, and to donate them for research purposes.
Analysis of the ova
Developed by Eugin's team of scientists, the study used six eggs from one of the women and ten from the other, and involved applying an innovative technique which allows viral material to be identified from very small sample quantities, such as human eggs. In this case, the result showed no presence of the viral RNA in any of the 16 oocytes tested.
So far, one of the main concerns regarding assisted reproduction therapies during the current Covid-19 pandemic has been the potential vertical transmission of SARS-CoV-2 infection via gametes and embryos prior to implantation. Accordingly, fertility clinics have been adhering to the precautionary principle, and implementing safety protocols when handling donor and patient material.
Since the new SARS-CoV-2 was first identified, it has been found to affect different tissues and organs. Yet, despite the large amount of scientific literature on the subject, the effect of the infection on a woman reproductive function had been little studied so far. Specifically, it was not clear whether the virus could infect human gametes and whether fertilised oocytes from women harbouring the virus could lead to infection of the developing embryo.
This new scientific finding further informs how to provide continuity of care for infertile patients in in-vitro fertilisation clinics despite pandemic situations like the current one.
Eugin Group's scientific director, Rita Vassena, stressed that "this is a key result for the reproductive field as it reveals an aspect of SARS-CoV-2 infection that we previously did not know." According to Vassena, "given that ours is the first finding of this type worldwide, we need to wait for independent confirmation, and if possible, at a larger scale. Nevertheless, it is very good news for our patients and represents a highly significant finding at a clinical level, as it allows us to adjust protocols and health staff actions within IVF clinics, and helps us advise our patients on their treatment during situations like the present one."
“Undetectable viral RNA in oocytes from SARS-CoV-2 positive women” by Monserrat Barragan et al. Human Reproduction journal.