On: COVID-19

Episode: 97

Date: March 2020

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

Key Subjects:

• COVID-19.
  • One of three 21^st century coronavirus pandemics:
    • SARS (2003), MERS (2012), COVID-19 (now).
  • SARS-CoV2 is the virus; COVID-19 is the disease which that virus spreads.
• “Perfect Storm” impact of COVID-19:
  • High in fatality and spreads fast.
    • SARS & MERS were higher in fatality, but didn’t spread as much.
  • Many get the virus but don’t get sick –> keep walking around and spreading the virus -> reaches more vulnerable groups.
    • Elderly (>70 years old).
    • Underlying conditions (heart disease, diabetes, hypertension).
  • Healthcare system overloaded.
    • Concentrated,high inflow into a system that doesn’t have a lot of spare capacity to begin with.
    • Healthcare workers and first responders are among the infected, further reducing capacity.
      • Regardless of age of healthcare workers.
      • Some evidence that they contract more severe versions of the virus.
      • 15% of healthcare workers infected in Wuhan became ill.
• US may have missed the boat on early intervention (testing).
  • Need to identify communities with significant levels of transmission and take action prior to cases ramping up.
• Convalescent plasma coronavirus therapy being tested as low-cost stop-gap solution.
  • Taking antibodies from individuals that have been infected and have since recovered.
• Vaccine development time-line much longer.
  • Trials need to clear very high approval thresholds given that you are looking to immunize healthy individuals.
  • Hotez team has developed potential vaccine but has no funding for clinical trials.

Comments

• The podcast mentions the potential impact of weather conditions on transmission of the virus.
  • In other words, could warmer weather slow down transmission?
• Some studies on the impact of weather condition on the transmission of SARS in Hong Kong in 2003 (here and here) seem to indicate that:
  • the ideal temperature range for transmission was 16-28 degrees Celsius. 
  • during days with lower temperatures the risk of transmission may have been higher.
• The SARS outbreak in Hong Kong was fairly concentrated in time.
  • Start to finish was a little over three months.
  • While the weather conditions varied, temperature on average was mostly within the range indicated above. 
• The graphs below are based on Hong Kong government data that I kept track of at the time (all information is for Hong Kong region only).
  • The number of daily active cases (defined as: existing cases plus new cases less discharged cases less fatalities):

• • The number of new cases and daily mean temperature (degrees in Celsius):