Risk of contamination with SARS-CoV-2 in ART.

Sir,

We read with interest the article by Kteily and colleagues regarding the non-detectability of SARS-CoV-2 mRNA in semen, follicular fluid, vaginal secretions and residual medulla in asymptomatic patients who undergo ART (Kteily ). Their study focused only on the presence of viruses in patients’ residual material samples. However, based on their findings, they curiously concluded that ‘no additional measures to prevent staff or cross-patient contamination need to be implemented in the IVF and andrology laboratories’.

This statement is far too general, not justified by the specific finding of authors, and may create a false and dangerous feeling of security both for patients and the staff. Cross-contamination issues in assisted reproduction are not restricted to physical contact with infected samples but involve other standard processes and activities. The SARS-CoV-2 pandemic aggravated these dangers considerably, including but not restricted to standard procedures of cryopreservation applied in the majority of IVF cycles.

As already discussed in this journal (Parmegiani and Vajta, 2021), contamination of liquid nitrogen and nitrogen vapour (LN2/NV) may occur at any step from manufacturing to final use, including transport, storage, distribution, preparation for cryopreservation and all stages of the procedure. Airborne contaminants such as SARS-CoV-2 can come into contact with LN2/NV and remain cryopreserved (Parmegiani ). Irrespective of a possible impact directly on gametes and embryos, the risk of cross-contamination from LN2/NV exists and may cause general symptoms, serious disease, death and further spreading (Scarica ). This fact has been acknowledged recently by many authors; they suggested implementing ‘good manufacturing’ practices in ART, including the use of single-personalized-disposable vitrification containers (Maggiulli ); the sterilization of liquid nitrogen before use (Arav, 2020; Alteri ); and the washing of cryopreserved specimens with sterile LN2 before thawing/warming (Hickman ; Shapiro ). Even the Sixth Edition (June 2021) of the “WHO Laboratory Manual for the Examination and Processing of Human Semen” suggests (i) the sterilization of LN2, (ii) the decontamination of cryopreserved specimens before warming and (iii) the periodic refilling of dewars/tanks with sterile LN2 (World Health Organization, 2021). Last but not least, some scientists cited by Kteily et al. for articles published a decade ago have since changed their minds regarding the negligibility of contamination risk. They now suggest taking precautions for the safe use of liquid nitrogen (Pomeroy and Schiewe, 2020).

Accordingly, while we congratulate the authors for the interesting research article, we suggest reconsidering their general conclusion and focusing their statement on the area that has been investigated in their present work.

Conflict of interest

L.P. reports fees from Origio-Coopersurgical and is a shareholder of Nterilizer Srl. G.V. is a shareholder and CSO at VitaVitro Biotech Co., Ltd., Shenzhen, China.