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Tuesday, April 7, 2020

Epidemiologist John Ioannidis of Stanford emphasizes the need for solid data to address COVID-19

From mid-March, 2020:

Writing in Stat, 
epidemiologist 
John Ioannidis 
of Stanford 
University 
emphasizes 
the need 
for solid data 
to address 
the coronavirus 
disease, Covid-19. 

Ioannidis 
is co- director 
of Stanford’s 
Meta-Research 
Innovation Center,
dedicated to 
improving 
the quality 
of scientific studies 
in biomedicine. 


Ioannidis wrote:
“At a time when everyone needs better information, from disease modelers and governments, to people quarantined or just social distancing, we lack reliable evidence on how many people have been infected with SARS-CoV-2, or who continue to become infected. 

Better information is needed to guide decisions and actions of monumental significance, and to monitor their impact.

The data collected so far on how many people are infected, and how the epidemic is evolving, are utterly unreliable. 

Given the limited testing to date, some deaths and probably the vast majority of infections due to SARS-CoV-2 are being missed. 


The one situation where an entire, closed population was tested was the Diamond Princess cruise ship, and its quarantined passengers. 

The case fatality rate there was 1.0%, but this was a largely elderly population, in which the death rate from Covid-19 is much higher.

Projecting the Diamond Princess mortality rate onto the age structure of the U.S. population, the death rate among people infected with Covid-19 would be 0.125%. 

But since this estimate is based on extremely thin data — there were just seven deaths among the 700 infected passengers and crew — the real death rate could stretch from five times lower (0.025%), to five times higher (0.625%). 

It is also possible that some of the passengers who were infected might die later, and that tourists may have different frequencies of chronic diseases — a risk factor for worse outcomes with SARS-CoV-2 infection — than the general population. 

Adding these extra sources of uncertainty, reasonable estimates for the case fatality ratio in the general U.S. population vary from 0.05% to 1%.

A population-wide case fatality rate of 0.05% is lower than seasonal influenza.

If that is the true rate, locking down the world with potentially tremendous social and financial consequences, may be totally irrational. 


If we decide to jump off the cliff, we need some data to inform us about the rationale of such an action, and the chances of landing somewhere safe.”