SARS-CoV-2 genomic RNA in corneal transplantation: Are corneal transplantations safe?

The lack of definitive knowledge about the presence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in corneal tissues has resulted in the recommendation to avoid using corneal tissue for transplantation when the tissue was obtained from donors with coronavirus disease 2019 (COVID-19) that had been confirmed or those who were exposed recently to COVID-19.

Evidence of SARS-CoV-2 in corneal tissue would seem to have clinical relevance for corneal transplantation, according to study investigators from the Department of Ophthalmology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.

Investigators conducted a case series the primary outcome of which was determination of the presence of SARS-CoV-2 viremia in corneal tissue samples.

The study included 11 deceased patients with confirmed COVID-19; the patients underwent autopsies between March 20 and May 14, 2020.

One corneal disc was obtained from each patient for molecular detection of viral genomic and subgenomic RNA, virus isolation, and immunohistochemistry.

The SARS-CoV-2 RNA loads were compared with RNA loads in the conjunctival and throat swab samples and aqueous humor, vitreous humor, and blood samples.

Findings
Of the 11 patients studies (6 women; mean age, 68.5 years), 10 (91%) died as a result of a COVID-19 infection; 1 death from hemorrhagic shock was considered a non-COVID-19-related death.

SARS-CoV-2 RNA was detected in 6 (55%) of the 11 corneal discs, and subgenomic RNA was detected in 4 (67%) of the 6 corneal discs with SARS-CoV-2 RNA. The virus could not be isolated in any of the corneal disc samples.

The patients with SARS-CoV-2 RNA detected in the corneal disc also tested positive for SARS-CoV-2 RNA in 4 of 6 conjunctival swab samples, 1 of 3 aqueous samples, 3 of 5 vitreous humor samples, and 4 of 5 blood samples.

Overall, conjunctival swab samples tested positive for SARS-CoV-2 RNA in 5 of the 11 cases. Postmortem SARS-CoV-2 viremia was detected in 5 of 9 patients, the authors reported. The findings were published in JAMA Ophthalmology.¹

This study confirmed its primary endpoint, i.e., that SARS-CoV-2 is present in human corneas.

Generally speaking, the investigators noted that disease transmission from donors to recipients is rare during corneal transplantations.

However, several viral diseases, i.e., HIV types 1 and 2, hepatitis B and C, rabies, and West Nile virus, are contraindications for corneal donations, whereas other viral diseases, such as influenza, are not contraindications for cornea donations.²

However, because not a great deal is known about SARS-CoV-2 in corneal tissue and possible transmission to the recipients of corneal tissue, corneal transplants from donors infected with COVID-19 or recently exposed to COVID-19 are avoided.

The authors concluded, “The potential of SARS-CoV-2 infection via a corneal transplant is low, but further research is warranted to assess the rate of SARS-CoV-2 transmission. The low RNA loads in corneal samples suggest a low risk of infection through a corneal transplant, even in a high-risk cohort of patients with viremia. Nevertheless, infection via a contaminated corneal graft cannot be fully excluded.”

References

1. Casagrande M, Fitzek A, Spitzer MA, et al. Presence of SARS-CoV-2 RNA in the cornea of viremic patients with COVID-19. JAMA Ophthalmol Published online January 21, 2021; doi:10.1001/jamaophthalmol.2020.6339

2. Desautels JD, Moshirfar M, Martheswaran T, et al. Risks posed to corneal transplant recipients by COVID-19-affected donors. Ophthalmol Ther 2020;9:371-379. doi:10.1007/s40123-020-00254-w