Skip to main content

  • COVID-19 patients show active, high viral shedding soon after symptom onset

    Comprehensive Ophthalmology

    Add to My Bookmarks

    Review of: Virological assessment of hospitalized patients with COVID-2019

    Wölfel R, Corman V, Guggemos W, et al. Nature, in press

    This paper presents virological assessment of patients diagnosed with COVID-19.

    Study design

    Researchers examined samples from 9 patients who were part of a large cluster of epidemiologically linked cases occurring after January 23, 2020, in Munich, Germany.

    Outcomes

    The authors observed very high viral shedding during the first week of symptoms, with a peak of 7.11 x 108 RNA copies/throat swab at day 4. In comparison, the SARS coronavirus from the 2003 outbreak reached peak viral shedding in 7 to 10 days after symptom onset with concentrations of up to 5 x 105 RNA copies/throat swab, suggesting that COVID-19 peaks earlier and at more than 1,000 times higher concentration.

    Virus was easily isolated from throat and lung samples but not stool samples; virus was not detected in urine or blood at any time point. Viral RNA continued to be shed from the sputum even after symptoms faded. Although 50% of patients experienced seroconversion after 7 days, it was not accompanied by a rapid decline in viral load.

    Limitations

    This study is limited by its small sample size.

    Clinical significance

    These findings show active and high levels of viral shedding from the upper respiratory tract early in the course of the infection when patients have relatively mild symptoms. This may, in part, explain the rapid spread of COVID-19. It calls into question whether current policies trying to mitigate spread of the virus are enough. From an ophthalmologist and clinician standpoint, I think we must assume every patient—regardless of symptoms and fever—could potentially carry the virus and take appropriate precautions.