The estimated risk of SARS-CoV- 2 infection via cornea transplant in Canada

Abstract

In late 2019 the respiratory illness, Corona Virus Disease-19 caused by the SARS-CoV-2 virus emerged in China and quickly spread to other countries. The primary mode of transmission is person-to-person via respiratory droplets. SARS-CoV-2 has been identified in conjunctiva. Transmission by cornea transplant has not been reported but is theoretically possible. We aimed to estimate the possible risk of transmission in Canada via cornea transplant during the first wave of the pandemic, and the potential risk reduction from testing decedents. We constructed a deterministic model in which the risk of transmission was estimated as the product of three proportions: decedents with SARS-CoV-2 infection, corneas that are NAT positive, and NAT positive corneas presumed to transmit. Risk was estimated according to 3 scenarios: most likely, optimistic and pessimistic. At the peak of the first wave of the pandemic risk was estimated to be 1 in 63,031 cornea transplants in Canada but could be as low as 1 in 175,821 or as high as 1 in 10,129. It would take 16 years at the peak infection of the first wave of the pandemic to observe 1 transmission. Testing would reduce the risk of 1 in 63,031 to 1 in 210,104 assuming 70% test sensitivity. The theoretical risk of SARS-CoV-2 transmission by cornea transplant is extremely low and decedent testing is unlikely to be beneficial.

Manifestations of coronavirus infection disease-19 in anterior eye segment: An up-to-date review

“…[ 53 54 55 ] Whereas, a recent analytical study showed a low risk of infection through corneal transplant. [ 56 ] Furthermore, several studies showed the existence of SARS-CoV2 in the conjunctival discharges and tears, which are potential ways for spreading the virus into the nasopharynx or eye contact. [ 2 57 58 59 60 61 62 63 64 65 ] However, according to a recent systemic review, no-cut clinical evidence demonstrated that eyes are a transmission pathway for COVID-19.…”

COVID-19 and Eye Banking: Ongoing Impacts of the Pandemic

“…The EBAA changed their clinical screening recommendations to be less exclusive by March 2022. 20 Although postmortem testing may be detecting additional COVID-19-positive donors not identified through EBAA clinical screening, given the very low risk of transmission, this benefit is likely negligible 29 and may not be worth the delay to patient care caused by the shortage of corneal tissue, particularly internationally. 35 This study may not be generalizable given the results reflect the experience from 1 eye bank that had a specific protocol for postmortem testing.…”

“…The risk of donor-recipient transmission of SARS-CoV-2 is likely very low, as evidenced by numerous studies. 17,18,[29][30][31] In fact, there have been at least 9 corneas transplanted from donors with COVID-19, with no reported transmission. 23 The current EBAA Medical Standards requirement of double povidone-iodine donor preparation is likely viricidal against SARS-CoV-2 within ocular tissue, further limiting the risk of transmission.…”