In examining 132 ocular tissues from 33 surgical-intended donors, researchers in the United States say they were able to identify the presence of SARS-CoV-2 RNA in approximately 13%. The investigators say this shows the presence of the virus extends beyond the conjunctiva and into structures such as the corneal epithelium. It also raises questions about the potential for non-respiratory route of transmission of coronavirus disease 2019 (COVID-19), the study shows.
These findings demonstrate the importance of donor screening guidelines, post-mortem nasopharyngeal polymerase chain reaction (PCR) testing, and povidone-Iodine (PVP-I) disinfection protocol in eyes destined for corneal transplantation, according to the study published in The Ocular Surface.
“In this study, for the first time, we report the presence of not only SARS-CoV-2 RNA but also its envelope and spike proteins in ocular tissues of donors who had COVID-19 at the time of death,” researchers report.
While previous research shows SARS-CoV-2 can be found in COVID-19 patients’ conjunctival swabs and tears, this study analyzed if it can be detected in human post-mortem tissues.
Researchers assessed the expression of SARS-CoV-2 RNA by real-time-(RT)-PCR in the corneal and scleral tissues of the 33 donors. These donors had been intended for surgery, but were eliminated from surgical use by the Eye Bank Association of America’s donor screening guidelines, or medical director review, or positive COVID-19 test. In 10 other research-intended eyes from COVID-19 positive donors, they evaluated ocular levels of SARS-CoV-2 RNA, envelope and spike proteins, and anti-SARS-CoV-2 IgG and IgM antibodies in the blood.
“Among 20 eyes recovered from 10 COVID-19 donors: 3 conjunctival, 1 anterior corneal, 5 posterior corneal, and 3 vitreous swabs tested positive for SARS-CoV-2 RNA,” according to investigators. “SARS-CoV-2 spike and envelope proteins were detected in the epithelial layer of the corneas that were procured without PVP–I disinfection.”
“Overall, our findings underscore the criticality of post-mortem PCR testing, PVP-I disinfection protocol, and donor screening guidelines in eye banking to eliminate the possibility of handling tissues with SARS-CoV-2 RNA particles,” the report says.
“While our data showed the presences of viral RNA and antigens in the corneas of COVID-19 patients, further studies are necessary to explore the possibility of transmission via ocular tissues and concentration dependent anti-virulent activity of PVP-I.”