Detection of SARS-CoV-2 in Simultaneously Collected Tear and Throat Swab Samples from the Patients with 2019- new SARS-CoV-2 Infection Disease: A Single Center Cross-sectional Study

Abstract

Objecive: This study aimed to evaluate whether Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) can be detected in the tears in the eyes of Coronavirus Disease 2019 (COVID-2019) infected patients and compare the detection consistency of two simultaneously collected samples, from the tears and throat swabs.Methods: A total of 35 COVID-2019 patients were included in this cross-sectional case series study. Throat samples from all enrolled patients were collected with sampling swab, and simultaneously, tear samples were collected with sampling swab from 9 patients (No.1-9) and with Schirmer's strip from the remaining patients (No.10-35) (bilateral eyes for all patients). Sample collecting and testing were performed in three separate time points: first from patients No.1-9, second from patients No.10-29, and third from patients No. 30-35. Reverse-transcriptase-polymerase-chain-reaction (RT-PCR) assay was performed.Results: Among enrolled patients, 29 (No.1-29) had mild or moderate clinical symptoms and 6 (No.30-35) had severe symptoms. The mean time interval from the sample collection day to diagnosis confirmation day was 9.71 ± 6.50 days (ranged from 3 to 29 days). None of the patients had conjunctivitis. Nineteen out of 35 (54.3%) throat samples presented positive Rt-PCR results. Three (no.13,21,31) out of 35 (8.6%) tear samples presented positive RT-PCR results. Two (no.21, 31) of these three patients were throat swab positive and one (No. 13) was negative. The consistency analysis indicated that tears and throat samples showed poor consistency (Kappa = -0.009, P = .9).The cycle threshold value (Ct-value) of tear samples collected by sampling swab was significantly higher than that by Schirmer's strip (t = 2.288, P = .03).Conclusion: In spite of the low SARS-CoV-2 positive detection rate of tear samples from COVID-2019 patients, we cannot fully rule out the transmission by ocular surface. Whether tear testing can be used as an aid in judging of SARS-CoV-2 infection need further investigation.

Keywords: COVID-2019; SARS-CoV-2; infection; tears; throat swab.