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Ocular swabs detect SARS-CoV-2 RNA in 57% of COVID-19 cases — Italian study

Genetic evidence of SARS-CoV-2, the virus that causes COVID-19, was found on the ocular surface of 57% of Italian COVID-19 patients, according to a study based on patients treated in the intensive care unit of a university hospital in Lombardy, Italy, one of the first major hot spots of the COVID-19 pandemic in Europe.

Doctors took conjunctival swabs from 91 patients hospitalised for COVID-19, which was clinically diagnosed by reverse-transcription polymerase chain reaction assay on nasopharyngeal swabs and by radiologic imaging, the authors said, and they also took swabs from 17 healthy volunteers who had no COVID-19 symptoms.

The investigators at the University of Insubria, Varese, Italy, detected SARS-CoV-2 RNA on the ocular surface of 52 of 91 patients with COVID-19 (57.1%; 95% confidence interval, 46.3% to 67.5%). In the 17 healthy volunteers, 10 had positive ocular swabs but negative nasopharyngeal swabs.

"Because patients may have positive test results with a conjunctival swab and negative results with a nasopharyngeal swab, use of the slightly invasive conjunctival swab may be considered as a supplementary diagnostic test," the authors said.

The infectivity of ocular material could not be determined from this study, the authors said.

 

Study details
SARS-CoV-2 on Ocular Surfaces in a Cohort of Patients With COVID-19 From the Lombardy Region, Italy

Claudio Azzolini; Simone Donati; Elias Premi; Andreina Baj; Claudia Siracusa; Angelo Genoni; Paolo A Grossi; Lorenzo Azzi; Fausto Sessa; Francesco Dentali; Paolo Severgnini; Giulio Minoja; Luca Cabrini; Maurizio Chiaravalli; Giovanni Veronesi; Giulio Carcano; Lorenzo S Maffioli; Angelo Tagliabue

Published in JAMA Ophthalmology on 4 March 2021

Abstract
Importance
Since February 2020, coronavirus disease 2019 (COVID-19) has spread rapidly all over the world, with an epidemiological cluster in Lombardy, Italy. The viral communicability may be mediated by various body fluids, but insufficient information is available on the presence of the virus in human tears.
Objectives
To investigate the rate of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in tears collected from patients with COVID-19 by means of real-time reverse transcriptase–polymerase chain reaction (rRT-PCR) assay and to assess the association of virus presence with concomitant clinical conditions.
Design, Setting, and Participants
Cross-sectional study conducted between April 9 and May 5, 2020. The setting was intensive care units at Azienda Socio-Sanitaria Territoriale (ASST) Sette-Laghi Hospital, University of Insubria, in Varese, Lombardy, Italy. A conjunctival swab was performed in 91 patients hospitalized for COVID-19, which was clinically diagnosed by rRT-PCR assay on nasopharyngeal swabs and by radiological imaging. Conjunctival swabs from 17 additional healthy volunteer participants with no symptoms of COVID-19 were examined to evaluate the availability and applicability of the conjunctival swab test.
Exposure
SARS-CoV-2 detection by means of rRT-PCR assay performed on the collected samples obtained by conjunctival swabs.
Main Outcomes and Measures
Conjunctival swab and nasopharyngeal swab results are reported, as well as demographic and clinical data.
Results
A total of 108 participants (mean [SD] age, 58.7 [14.2] years; 55 female and 53 male) were tested for SARS-CoV-2 using rRT-PCR assay, including 91 patients hospitalized with COVID-19 and 17 were healthy volunteers. SARS-CoV-2 was found on the ocular surface in 52 of 91 patients with COVID-19 (57.1%; 95% CI, 46.3%-67.5%), with a wide variability in the mean viral load from both eyes. Among a subset of 41 patients, concordance of 63.0% (95% CI, 41.0%-81.0%) was found between positive conjunctival and nasopharyngeal swab test results when performed within 2 days of each other. In 17 of these patients, nasopharyngeal swab results were negative for SARS-CoV-2. In 10 of these 17 patients, conjunctival swab results were positive for the virus.
Conclusions and Relevance
In this study, SARS-CoV-2 RNA was found on the ocular surface in a large part of this cohort of patients with COVID-19, although the infectivity of this material could not be determined. Because patients may have positive test results with a conjunctival swab and negative results with a nasopharyngeal swab, use of the slightly invasive conjunctival swab may be considered as a supplementary diagnostic test.

 

[link url="https://jamanetwork.com/journals/jamaophthalmology/fullarticle/27771"]JAMA Ophthalmology study (Open access)[/link]

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