To understand the threat of COVID-19, look at hospitalizations, not just death rate

These thoughts are once again my own, though I'm drawing heavily on data and reporting that's already in public circulation. Reposting from my Facebook account, and edited for updates and clarity.

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I'm seeing a steady drip of comments urging perspective in the midst of the COVID-19 crisis, suggesting that actions being taken by governments are too drastic and are not proportionate to the true threat. Most of these comments cite the 1-3% case fatality rate of COVID-19, and point out that we keep on going with life and business while accepting the risks involved -- and therefore the extreme measures being undertaken now may be uncalled for. John Ioannidis, who has done critically important work on the reproducibility crisis in science, wrote a piece in STAT to this effect (h/t Ryan Stephens); Senator Ron Johnson said much the same in interviews over the last week or so. 

I do appreciate the perspective that Ioannidis brings, especially that our data on the pandemic within the US is heavily skewed because of the lack of testing. The true death rate over all cases might indeed be lower than current estimates (1.4% in Wuhan, by one report), which would be very welcome news. He also rightly highlights the enormous social and economic costs that are borne by millions as a result of aggressive government restrictions to blunt community spread. However, to understand the impact of this disease, I think the HOSPITALIZATION rate, not the death rate, is the key statistic to focus on. (A good response to Ioannidis' piece can be found here.)

The exact proportion of patients infected with SARS-CoV-2 who require hospitalization is difficult to pin down -- estimates put that number at anywhere between 10-15%. A smaller proportion of cases will require ICU support --in China, this was about 5% of cases that tested positive, while the number was higher in Italy at 12% (https://jamanetwork.com/journals/jama/fullarticle/2763188). As many have pointed out, the exponentially growing number of cases in the US, coupled with the proportion of patients that will need hospitalization or intensive care, means that we are dangerously close to the point where our healthcare system will start getting overwhelmed.

It is true that the flu places a significant strain on our healthcare system every year, and we've learned to live with that strain. This season, the flu has killed ~20,000 people, caused ~350,000 hospitalizations, and infected about 34 million people (https://www.nytimes.com/2020/02/29/health/coronavirus-flu.html). That's less than a 0.01% fatality rate, and only 1% require hospitalizations. But please remember that while our healthcare system is geared to handle the surge in cases from seasonal influenza (aided each year by a widely available vaccine), it is now additionally grappling with a pandemic that is almost TWICE as infectious, requires substantially MORE hospitalizations among positive cases, and has a significantly HIGHER death rate. Several hundred cases last week has turned into 11,000 cases as of this afternoon. This is a function of both exponential math and the increased testing capacity in the US, and that's why we need to buy our healthcare system as much time and resources as we can RIGHT NOW.

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Now, some good news. I don't believe that our only options are (i) long-term social distancing or (ii) overwhelmed healthcare systems. I've been incredibly heartened to see research institutes, biotechs, and pharma companies banding together, sharing resources, and searching for every possible therapy that can be brought to bear on COVID-19. I've written before on treatments and vaccines currently in development, and I'm personally very intrigued by reports that the anti-malarial chloroquine has been reported to have efficacy by investigators in China, France, and Australia, among others (https://www.businessinsider.com/malaria-pill-chloroquine-tested-as-coronavirus-treatment-2020-3). I'm also very happy to see this possibility considered today at the highest levels of the US response. I'm anxious to see clinical data on this -- chloroquine is cheap and safe, and could scale much faster than some of the biologic or cell-based therapies that are being explored for COVID-19 treatment. Finding a successful and scalable treatment would be absolutely critical in stopping this pandemic in its tracks.

It's hard to do, but the best thing we can do for each other right now is to stay apart. By doing so, we buy our healthcare system time to take care of the critically ill, spread out available resources, and bring new treatments to the fight. We'll get through this!