Most asymptomatic COVID-19 patients remain asymptomatic

Three-quarters of COVID-19 patients with mild or no COVID-19 symptoms, who were admitted to community treatment centres in South Korea for isolation, remained asymptomatic during their time in isolation, a study suggests.

Welcome to The Medical Republic‘s live COVID-19 blog.

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The latest

• Afternoon update: three-quarters of asymptomatic COVID-19 patients remain asymptomatic.
• Morning update: dexamethasone may reduce mortality in ventilated COVID-19 patients, study finds.
• Sixteen new COVID-19 cases recorded in Victoria yesterday.

4.40pm, 23 June

• Three-quarters of COVID-19 patients with mild or no COVID-19 symptoms remain asymptomatic during the course of infection, a study suggests.
  Writing in Emerging Infectious Diseases, researchers reported the outcomes of an observational cohort study in 568 people who tested positive for SARS-CoV-2 and had only mild or non-existent symptoms, who were kept in isolation at one of three community treatment centres in South Korea established for that specific purpose.
  Two-thirds of the patients were female, the mean age was 36 years, and around 90% were asymptomatic at admission. Just over 75% of the cohort remained asymptomatic for the duration of their confinement, which was a mean of 19 days.
  The isolation centres were set up for people who could not self-isolate at home for medical or non-medical reasons, and included children and infected family groups.
  “Isolation facilities for mild cases were vital to helping overcome COVID-19 outbreaks in the country, particularly because >80% of cases were not severe and did not require special therapies, such as oxygen supplementation or parenteral fluid infusion,” the authors wrote.
  The study – and the centres – excluded any individuals with comorbidities that may have increased their risk of severe disease, such as cardiovascular disease, obesity, or haematological malignancy.
  Commenting on the high proportion of asymptomatic individuals, the authors noted that ‘extensive and aggressive’ testing was carried out among close contacts of infected individuals, particularly among a specific religion group that experienced a large outbreak.

12.10pm, 23 June

• The UK-based RECOVERY trial has published the results of its dexamethasone trial, albeit on the non-peer-reviewed preprint server MedRxiv, suggesting the steroid was associated with significantly lower mortality in COVID-19, particularly among ventilated patients, those under 70 years, and male.
  The open-label study randomised 2014 patients to daily oral or intravenous dexamethasone and 4321 to usual care (which included dexamethasone in 7% of the usual care patients). Overall, 17% fewer patients in the dexamethasone arm died within 28 days compared to those who received usual care. However among patients receiving mechanical ventilation, dexamethasone was associated with a 35% relative reduction in 28-day mortality – a 3% absolute reduction – and among those receiving oxygen therapy there was a 20% reduction. There was no benefit seen in patients who weren’t on any respiratory support, nor was there any benefit seen in patients who had had symptoms for less than seven days before randomisation.
  The study noted that patients who were on mechanical ventilation tended to be younger and have a longer duration of symptoms. Sub-group analysis also pointed to an effect of age and sex: significant mortality benefits were seen in those aged under 70 years but not over 70s, and in men but not women.
  Dexamethasone was also associated with a slightly shorter duration of hospital stay than usual care – 12 days compared to 13 days – and patients in the treatment arm were 11% more likely to be discharged from hospital within 28 days.
  The authors commented that corticosteroids are often used in respiratory syndromes such as SARS, MERS, severe influenza and pneumonia, although the evidence supporting this use has been ‘very weak’.
  “It is likely that the beneficial effect of corticosteroids in severe viral respiratory infections is dependent on using the right dose, at the right time, in the right patient,” they wrote.
  Given the results, they called for a change to current recommendations which advise against corticosteroid use in COVID-19.
  “Dexamethasone provides an effective treatment for the sickest patients with COVID19 and, given its low cost, well understood safety profile, and widespread availability, is one that can be used worldwide.”

8.45am, 23 June

• Victoria recorded 16 new cases of COVID-19 yesterday, but removed five existing cases from the count because they were ‘duplicates’. Six of the new cases are linked to known outbreaks such as the Stamford Plaza Hotel, H&M Northland, and Albanvale Primary School; five were picked up in routine testing, four are in returned travellers in hotel quarantine, and one is under investigation.
  Around Australia to 9pm yesterday, the COVID-19 infection figures are as follows:
  National – 7474, with 102 deaths and 6903 recovered
  ACT – 108
  NSW – 3151
  NT – 29
  QLD – 1066
  SA – 440
  TAS – 228
  VIC – 1847
  WA – 605