Governance Organization

SMH – St. Michael’s Hospital Medical Services Association

Project Title

SMH-21-009 – Evaluation and management of viral shedding and transmissibility in tears and conjunctival secretions of patients with COVID-19

Project Highlights


Conjunctivitis may be a common early sign of COVID-19. The viral shedding in tears has been reported in patients without any ocular symptoms. Despite the association of conjunctivitis with positive conjunctival swabs for SARS-CoV-2, ophthalmologists have no means of identifying patients at high risk of transmitting the virus through ocular secretions. Additionally, it is unknown whether the cytokine profiles of tears are different in patients with SARS-CoV-2 relative to the general population.

A better understanding of the ocular manifestations, cytokine profile and viral prevalence of COVID-19 will facilitate the diagnosis and prevention of disease transmission amongst patients and healthcare providers.


To compare the presence of SARS-CoV-2 viral shedding and cytokine profiles in conjunctival secretions of a large series of patients who have tested positive for COVID-19 relative to a subset of patients with a negative test. Experimental design Prospective multi-center cohort study.


Adults ≥18 years of age at the time of enrolment, ambulatory or hospitalized patients, and patients with confirmed SARS-CoV-2 infection will be enrolled. Diagnosis of COVID-19 will be made via a positive real-time polymerase chain reaction (PCR) on at least two specific genomic targets or a single positive target with sequencing and confirmed by NML by nucleic acid testing, consistent with current public health guidelines in Ontario.

Study Procedures

At the time of initial enrollment and confirmation of COVID-19 test results, a dedicated research staff member will obtain conjunctival swabs for SARS-CoV-2 using a disposable sampling swab to collect tears and secretions from the lower eyelid fornix of each eye (3-5 μl) with a 10 μl capillary tube. At the time of specimen collection, vírus neutralization will occur via rinsing into 1% triton X-100 inactivating solution. The Bio-Plex Pro Human Cytokine 27-Plex Immunoassay Kit will be used to examine cytokine levels in ocular secretions. The primary outcome will be to establish the incidence of detectable SARS-CoV-2 viral shedding in conjunctival swab samples of patients with confirmed COVID-19, and to evaluate the cytokine profile in these patients relative to healthy controls. The secondary outcome will be to define the incidence of false positives for detection of SARS-CoV-2 conjunctival swabs samples of patients with confirmed negative COVID-19 test results.

Data Analysis

The incidence rate of detected SARS-CoV-2 in conjunctival swab samples via PCR testing of patients with and without COVID-19 will be compared. Categorical variables will be reported as counts and percentages and will be compared using a chi-squared test or Fisher’s exact test. Cytokine values using a standard assay will be recorded as continuous variables and reported as a mean with standard deviation or median with minimum and maximum values. These parameters will be compared using a Mann-Whitney U test. Coefficients with 95% confidence intervals will be reported. A p-value of 0.05 will be considered for statistical significance.


Prevention and Treatment

Primary Project Lead for Contact

Dr. Rajeev Muni


Secondary Project Lead for Contact

Dr. Marko Popovic


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