John P.A. Ioannidis points out that data is important, and we don’t have enough of it yet to justify making the world-altering decisions we’re currently making:
Reported case fatality rates, like the official 3.4% rate from the World Health Organization, cause horror — and are meaningless. Patients who have been tested for SARS-CoV-2 are disproportionately those with severe symptoms and bad outcomes. As most health systems have limited testing capacity, selection bias may even worsen in the near future.
The one situation where an entire, closed population was tested was the Diamond Princess cruise ship and its quarantine 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%.
That huge range markedly affects how severe the pandemic is and what should be done. 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.
And Issues & Insights asks, “Is the media ignoring good news on coronavirus?”:
Meanwhile, data collected by the Centers for Disease Control and Prevention show that – when measured by date of onset rather than the day officially reported — the number of new COVID-19 cases peaked on March 9 at 194, then dropped to 172 on March 10. It was 174 on March 11. It plunged to 122 on March 12, although the CDC cautions that there may be onsets that day that haven’t been reported yet. In any case, all this was before the most draconian restrictions were put in place.
It’s far too early to draw any conclusions, but it certainly doesn’t look like an out-of-control plague, as commonly depicted by the press.
My opinion remains that the Wuhan Flu is a serious health issue, and people in vulnerable groups — the elderly, people with a history of respiratory issues — should take extra precautions up to and including quarantining themselves. But everybody else needs to get back to work.