Coronavirus COVID-19 Update for June 17, 2020

SARS-CoV-2 shedding and seroconversion among passengers quarantined after disembarking a cruise ship: a case series
Patients on board the Diamond Princess cruise ship, which was quarantined because of an onboard outbreak of COVID-19 in February, 2020, provided an opportunity to define the shedding pattern of SARS-CoV-2 and patient antibody responses before and after the onset of symptoms. Authors find that patients with COVID-19 can develop asymptomatic lung infection with viral shedding and those with evidence of pneumonia on imaging tend to have an increased antibody response. Positive IgG or IgM confirmed infection of COVID-19 in both symptomatic and asymptomatic patients. A combination of RT-PCR and serology should be implemented for case finding and contact tracing to facilitate early diagnosis, prompt isolation, and treatment.

Low-cost dexamethasone reduces death by up to one third in hospitalised patients with severe respiratory complications of COVID-19 (Press release)
In March 2020, the RECOVERY (Randomised Evaluation of COVid-19 thERapY) trial was established as a randomised clinical trial to test a range of potential treatments for COVID-19, including low-dose dexamethasone. Dexamethasone reduced deaths by one-third in ventilated patients and by one fifth in other patients receiving oxygen only). There was no benefit among those patients who did not require respiratory support. Based on these results, 1 death would be prevented by treatment of around 8 ventilated patients or around 25 patients requiring oxygen alone. Full details of the study protocol and related materials are available at www.recoverytrial.net

Shedding of infectious virus in hospitalized patients with coronavirus disease-2019 (COVID-19): duration and key determinants
Authors assessed shedding of SARS-CoV-2 RNA and infectious virus in hospitalized patients, 89 intensive care and 40 medium care. Infectious virus shedding was detected in 23 of the 129 patients (17.8%). The median duration of shedding was 8 days post onset of symptoms and the probability of detecting infectious virus dropped below 5% after 15,2 days post onset of symptoms. Multivariate analyses identified viral loads above 7 log₁₀ RNA copies/mL as independently associated with isolation of infectious SARS-CoV-2 from the respiratory tract. A serum neutralizing antibody titer of at least 1:20 was independently associated with non-infectious SARS-CoV-2. Patients with severe or critical COVID-19 may shed infectious virus for longer periods of time compared with patients with mild COVID-19. Infectious virus shedding drops to undetectable levels below a viral RNA load threshold and once serum neutralizing antibodies are present, which warrants the use of quantitative viral RNA load assays and serological assays in test-based strategies to discontinue or de-escalate infection prevention and control precautions.