COVID19 update, July 18, 2020: six severity levels based on symptoms; about 90% of infections in young children are asymptomatic; ivermectin results in humans promising

(1) Dr. John Campbell on the current situation in the UK

A few points for the impatient:

  • antibody testing indicates that the official case numbers are an underestimate by about a factor of ten
  • however, based on data from Sweden where they were able to test for memory T-cells (a much harder test), about twice as many people have immunity as the simpler antibody test indicates
  • That corresponds, in aggregrate, to a Dunkelziffer (hidden infection rate) of about 20:1
  • about 6% of school children in the UK have antibodies. Significantly, only 1 on 10 of them reported ever having had any symptoms. Or, to put it differently, 90% of cases in that age bracket are asymptomatic. I have been suspecting for a while that not just severity of the disease is age-dependent, but also the rate of symptomatic infection.

(2) An article in the Daily Telegraph comments on a recent study analyzing responses to an AI-driven diagnostic tool. As a control, the trained AI was applied to a different set of patients and validated against more conventional diagnoses.

The trouble with machine learning is that, while it’s great at “imitation games”, it’s not so great at answering Eugene Wigner’s plea: ‘I’m glad that the computer understands it — now I want to understand it too’. That being said, six clusters of cases emerged with six distinct sets of symptoms. Arranged in ascending order of severity:

1. (Flu-like with no fever): Headache, loss of smell, muscle pains, cough, sore throat, chest pain, no fever. [1.5% require respiratory support of any kind]

2. (Flu-like with fever): Headache, loss of smell, cough, sore throat, hoarseness, fever, loss of appetite.[4.4% require respiratory support of any kind]

3. (Gastrointestinal): Headache, loss of smell, loss of appetite, diarrhoea, sore throat, chest pain, no cough.[3.3% require respiratory support of any kind]

4. (Severe level one, fatigue): Headache, loss of smell, cough, fever, hoarseness, chest pain, fatigue.[8.6% require respiratory support of any kind]

5. (Severe level two, confusion): Headache, loss of smell, loss of appetite, cough, fever, hoarseness, sore throat, chest pain, fatigue, confusion, muscle pain.[9.9% require respiratory support of any kind]

6. (Severe level three, abdominal and respiratory): Headache, loss of smell, loss of appetite, cough, fever, hoarseness, sore throat, chest pain, fatigue, confusion, muscle pain, shortness of breath, diarrhoea, abdominal pain. [19.9% require respiratory support of any kind]

(3) Aerosol transmission: this group from Amsterdam https://www.medrxiv.org/content/10.1101/2020.07.16.20155572v1.full.pdf

experimentally studied the spread of droplets and aerosols from healthy subjects breathing, speaking, and coughing. They conclude that aerosol transmission will be an inefficient route.

(4) Dr. Seheult on some new results that seem to show ivermectin, earlier hown to inhibit COVID-19 in the test tube, is actually fairly potent in human patients https://papers.ssrn.com/sol3/papers.cfm?abstract_id=3636557

Dr. Seheult discusses possible mechanisms, as well as the role of von Willebrand factor in blood clotting

One thought on “COVID19 update, July 18, 2020: six severity levels based on symptoms; about 90% of infections in young children are asymptomatic; ivermectin results in humans promising

  1. I think you’ve linked similar material earlier, but this lengthy video includes a discussion about Covid in kids, in which it is argued that for ages 0-10, kids are pretty much invulnerable. However, older children get reactions closer to what adults experience.
    Starts at about the 15 minute mark.

    The State of the Pandemic, Opening the Schools, and the Outbreak at San Quentin State Prison
    UCSF School of Medicine

    One of a series of regular broadcasts.

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