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Coronavirus shows low risk for being spread through tears

Rupesh Agrawal

SARS-CoV-2 is known to be transmitted via droplets, but infected patients are unlikely to spread the virus through tears, according to a study.

“In our study, we could not find any evidence of viral shedding in tears taken at various time points over the course of disease in COVID-19-positive patients. Hence, this study suggests lower probability of disease transmission through tears,” Rupesh Agrawal, MD, a senior consultant ophthalmologist in Singapore, told Healio/OSN.

A prospective study evaluated the possibility of SARS-CoV-2 transmission through tears by assessing the presence of SARS-CoV-2 with viral isolation and quantitative reverse transcription polymerase chain reaction (RT-PCR). Patients were monitored via routine nasopharyngeal swabs, and tears were examined to understand patterns of viral shedding.

SARS-CoV-2 is known to be transmitted via droplets, but infected patients are unlikely to spread the virus through tears.

Researchers at National Center for Infectious Disease, Tan Tock Seng Hospital collected tear samples from 17 patients with COVID-19 from initial symptoms until recovery, usually by day 20. The tears were sampled using Schirmer’s test strip at varying time points between day 3 and day 20 after initial development of symptoms. None of the patients presented with ocular symptoms, but one patient developed conjunctival injection and chemosis during the hospital stay.

The virus was not detected in 64 tear samples taken during the study period, with 12, 28 and 24 samples taken during the first week, second week and third week, respectively, of initial symptoms. All tested negative for SARS-CoV-2 on viral isolation and RT-PCR. However, viral load was detected in nasal and throat swabs. Further studies are needed to establish tears as a potential source of transmission, Agrawal said. – by Robert Linnehan

Disclosures: The authors report no relevant financial disclosures.

Editor's Note: This article has been updated to correct the name of the research hospital.

Rupesh Agrawal

SARS-CoV-2 is known to be transmitted via droplets, but infected patients are unlikely to spread the virus through tears, according to a study.

“In our study, we could not find any evidence of viral shedding in tears taken at various time points over the course of disease in COVID-19-positive patients. Hence, this study suggests lower probability of disease transmission through tears,” Rupesh Agrawal, MD, a senior consultant ophthalmologist in Singapore, told Healio/OSN.

A prospective study evaluated the possibility of SARS-CoV-2 transmission through tears by assessing the presence of SARS-CoV-2 with viral isolation and quantitative reverse transcription polymerase chain reaction (RT-PCR). Patients were monitored via routine nasopharyngeal swabs, and tears were examined to understand patterns of viral shedding.

SARS-CoV-2 is known to be transmitted via droplets, but infected patients are unlikely to spread the virus through tears.

Researchers at National Center for Infectious Disease, Tan Tock Seng Hospital collected tear samples from 17 patients with COVID-19 from initial symptoms until recovery, usually by day 20. The tears were sampled using Schirmer’s test strip at varying time points between day 3 and day 20 after initial development of symptoms. None of the patients presented with ocular symptoms, but one patient developed conjunctival injection and chemosis during the hospital stay.

The virus was not detected in 64 tear samples taken during the study period, with 12, 28 and 24 samples taken during the first week, second week and third week, respectively, of initial symptoms. All tested negative for SARS-CoV-2 on viral isolation and RT-PCR. However, viral load was detected in nasal and throat swabs. Further studies are needed to establish tears as a potential source of transmission, Agrawal said. – by Robert Linnehan

Disclosures: The authors report no relevant financial disclosures.

Editor's Note: This article has been updated to correct the name of the research hospital.

    Perspective
    Jack S. Parker

    Jack S. Parker

    In Albert Camus’ “The Plague,” our narrator notes how “… the perplexity of the early days gradually gave place to panic.” And while we fervently hope that our own story of quarantine will differ entirely from Camus’, we do share the same starting point: perplexity. The world has been blindsided by the highly improbable, extreme impact event — N.N. Taleb’s “Black Swan” — one in which radical uncertainty predominates and in which we enter a true emergency period where we must learn, and learn quickly, in the face of the new observed reality.

    Jun and colleagues have made a high-profile attempt to gather some of this necessary knowledge in their forthcoming publication, “Assessing viral shedding and infectivity of tears in coronavirus disease 2019 (COVID-19) patients.” From samples of tears obtained from 17 infected patients (none of whom displayed any overt ocular involvement), they conclude there is little evidence that COVID-19 is transmissible by tears alone in patients without active conjunctivitis.

    If these findings are correct, it would suggest that “eye rubbers” are not more likely disease transmitters, and that Goldmann applanation is not particularly high-risk.

    However, these results should be interpreted with caution. The absence of evidence does not equate to evidence of absence, and it certainly remains theoretically plausible that COVID-19 could be transmitted though the tear-film, this 3-week study of 17 patients notwithstanding.

    A true test of these results would be inoculating noninfected individuals with tears collected from the infected. I cannot imagine there would be any volunteers for such a study.

    There is a danger in thinking that we know more than we do, and a general precautionary principle may be best applied. In the meantime, we should be researchers, not philosophers, and empiricists, not theorists. And, above all, we should be alert to the cardinal logical fallacy that generates black swans in the first place; that “all you see is all there is.”

    • Jack S. Parker, MD, PhD
    • Birmingham, AL

    Disclosures: Parker reports no relevant financial disclosures.

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