Presence of SARS-CoV-2 RNA in human corneal tissues donated in Italy during the COVID-19 pandemic

Objective To analyse corneal tissues from asymptomatic donors with a postmortem nasopharyngeal swab tested positive for the presence of SARS-CoV-2 RNA, and therefore, understand the role that corneal transplantation may have in viral transmission. Methods and analysis Between March 2020 and October 2021, 101 corneas (out of 8154 collected in Italy) from 51 donors (out of a total of 4155 Italian donors) positive for SARS-CoV-2 after postmortem nasopharyngeal swab tests were analysed for the presence of SARS-CoV-2 RNA through real-time RT-PCR. When available, the corneal tissue storage media were also assessed. Corneas and/or storage media with confirmed presence of SARS-CoV-2 RNA were further investigated by isolating SARS-CoV-2 virions, which were used to infect VeroE6 target cells. Results Only N=4 corneas and/or storage media out of 101 showed presence of SARS-CoV-2 RNA. No VeroE6 cell infection was detected with viral isolates, thus suggesting no presence of SARS-CoV-2 virions in corneal specimens and storage media. Conclusions The presence of SARS-CoV-2 in cornea specimens would seem to be more likely due to prolonged detection of RNA rather than to active viral replication, with very low risk of infectivity and transmission through keratoplasty.