On: COVID-19 (Continued)

Episode: 99

Date: March 2020

Background: Scientist, pediatrician, and advocate in the fields of global health, vaccinology, and neglected tropical disease control.

Key Subjects:

• No real sense of actual number of cases (% of population infected).
  • Geographical distribution of cases (density) probably more important than absolute number of nationwide cases.
• Multiple of actual to confirmed cases could be about 10-20x (estimate as of March 20).
  • Based on estimated days to mortality and mortality rate.
  • Means there could be about 100-200k cases in the US, spread over various centers.
• US hospitals starting to become overwhelmed.
  • Lack of state/federal coordination.
  • Healthcare professionals are getting sick.
  • Shortage of equipment.
• Inconsistency in age range of infections across countries.
  • About 1/3 of US hospital cases is 20-40 year age range, about 50% under 54.
  • Different from China.
  • Fatality rate not as high in lower age group, but still fairly severe symptoms and perhaps long-term implications.
  • Reasons not clear: vaping? [or, as per Comments below, high blood sugar may be a relevant underlying symptom that is more prevalent in the US?]
• Potential treatment options.
  • Plasma from recovered patients.
  • Repurposed drugs, such as:
    • Chloroquine (cheap malaria drug).
    • Remdesvir (ebola).
    • ARBs (angiotensin-receptor blockers).
  • Vaccine: takes time.
• Toxic mix ensures rapid transmission and high number of fatalities.
  • Rate of transmission (fairly high).
  • Rate of fatality (fairly high).
  • Asymptomatic individuals (not all cases are immediately symptomatic).

Comments

• Excellent video explanation of ACE-2 receptors, Ace-inhibitors and ARBs here.
• Some related points from a Twitter thread by David Sinclair, biologist, genetics professor:
• SARS-CoV2 attacks pneumocytes in the lungs, intestine, heart and the cells lining blood vessels.
• In the lungs, CoV2:
  • Prevents cells from making biological detergents to keep lung passages open.
  • Acute respiratory distress follows.
  • Oxygen levels fall.
• There may be a dangerous underlying process.
  • COVID-19 may also involve abnormal blood production.
  • CoV genes may interfere with heme, the red compound in blood, by kicking out the iron.
• This would explain why chloroquine seems effective as a treatment.
  • Chloroquine prevents the attack on heme.
• This may also explain why diabetics and elderly are more susceptible.
  • Blood sugar levels usually increase as we get older.
  • This increases the amount of glycated hemoglobin (HbA1c).
  • The virus may more easily disrupt the heme in red blood cells.
• If so, the virus:
  • Destroys the lung so patients can’t take up oxygen, AND
  • Reduces the body’s ability to carry oxygen.