Why COVID became a pandemic:
1) New virus
2) Large susceptible population 3) No antiviral/vaccine against this virus class
4) Delays/Failures in implementing border control & universal masks
5) High proportion of asymptomatic infections which facilitated easy unsuspecting spread
1) New virus
2) Large susceptible population 3) No antiviral/vaccine against this virus class
4) Delays/Failures in implementing border control & universal masks
5) High proportion of asymptomatic infections which facilitated easy unsuspecting spread
The first 4 of these reasons were also true of the other 2 recent corona virus epidemic prone outbreaks: SARS and MERS.
They were actually more serious. But SARS & MERS almost always caused symptoms. So you could identify patients with infections and prevent spread more easily.
They were actually more serious. But SARS & MERS almost always caused symptoms. So you could identify patients with infections and prevent spread more easily.
Many estimates of the proportion of COVID19 infections that are asymptomatic have been published. I’m sticking with my estimate from April: approximately 80%.
Subsequent data from Antarctica cruise, Peru etc support this level of asymptomatic disease
Subsequent data from Antarctica cruise, Peru etc support this level of asymptomatic disease
Given that asymptomatic infections are the single most problematic feature of COVID transmission is why we need:
-Adequate Testing
-Universal masks
-Social distance as much as possible even from people who look and feel perfectly fine
-Contact tracing and preemptive quarantine
-Adequate Testing
-Universal masks
-Social distance as much as possible even from people who look and feel perfectly fine
-Contact tracing and preemptive quarantine
Hats off to @zeynep for identifying asymptomatic transmission of COVID as one of the biggest problems in March, when she argued for masks for everyone not just sick people— ahead of CDC and WHO. Prescient. @nytimes @benyt @jeremyphoward google.com/amp/s/www.nyti… 👇👇 
And hats of to @jeremyphoward who recognized the same thing and started #Masks4All masks4all.co/about-us/
I’m glad @zeynep and @jeremyphoward didn’t stay in their lane. Many in the lane missed the boat, and joined in late.
I’m glad @zeynep and @jeremyphoward didn’t stay in their lane. Many in the lane missed the boat, and joined in late.
Hats off also to @trishgreenhalgh an evidence based medicine pioneer who challenged rigid proponents of EBM to not use “following the science” as a defense against what should be common sense interventions. bostonreview.net/science-nature…
