SARS-CoV-2 in tears

illustration of tear drops

Due to COVID-19 disease spreading at an unprecedented pace, efficient diagnostic and treatment modalities are needed to limit its spread and curb the death toll. COVID-19 is currently diagnosed by a real time RT-PCR test on respiratory specimens. However, the test has suboptimal turnaround time and requires collecting samples using deep nasopharyngeal swabs. Public health authorities and clinicians have strongly expressed an urgent need for an efficient and convenient sampling method with greater accuracy in detection.

In this study led by Hossein Nazari, MD, a vitreoretinal surgeon and instructor in the Department of Ophthalmology and Visual Neurosciences, researchers will examine if pure tear fluid using microcapillary tubes will provide a higher yield for virus detection and be a more comfortable and efficient sampling regimen compared with the current method using nasopharyngeal swabs.

“Tears are a known source of biomarkers for ocular and systemic diseases,” said Nazari. “COVID-19 and similar viruses have been variably detected in tears. This variable detection is mostly due to using different types of swabs with inconsistent virus recovery rates. We will examine if the tear production system sheds virus and if tears contain enough virus to be detected with our tests.”

To collect the tears for testing, researchers will place a microcapillary tube at the corner of a patient’s eyelid so tears can be absorbed into the tube without causing any trauma. The tears will be compared to standard nasopharyngeal swabs.
“We hypothesize that the rate of detection of COVID-19 in pure tear samples collected with microcapillary tubes is equal to results in nasopharyngeal swabs,” said Nazari.

This project is supported by the UMN Campus Public Health Officer's CO:VID (Collaborative Outcomes: Visionary Innovation & Discovery) grants program, which support University of Minnesota faculty to catalyze and energize small-scale research projects designed to address and mitigate the COVID-19 virus and its associated risks.