Right after I posted the “Coronavirus act now” plea on Facebook, a friend published another post on another platform arguing that

“only 13.8% of COVID-19 cases need hospitalization, and only 0.9% die in places in China outside of Hubei Province. ” “Therefore, COVID-19 is indeed a big flu, and the situation will be much better when it happened in countries with advanced healthcare systems. No need to panic. ”

In Wuhan, patients were treated in the hallways because there were no beds available. Some died at home while waiting for beds. Healthcare workers in Hubei Province only slept 2–3 hours a day before China pulled 42,000 healthcare workers from other provinces to join the rotation. While lots of people were dying from having no access to life support when they were infected with coronavirus, people also dying from having no access to medical support for other diseases, such as cancer and kidney failure.

San Francisco is a city where 47 mi² land hosts more than 800,000 people, most of which commute by public transportation. Since the breakout from the end of January, the government had not taken any proactive measurements until the past few days. People were still living their lives as if nothing had happened until the past few days. Everything was going on the trajectory of Wuhan, except stocking up groceries and toilet paper.

Watching all these, I always thought the city of San Francisco was inevitably falling under the attack of coronavirus.

But are we really?

Intrigued by his post, I did some back-of-the-envelope calculation to see when people will start dying from having no access to life support, based on data that I was able to look up briefly.

TL-DR: Based on a back-of-the-envelope calculation using available data and reasonable assumptions, SF hospital acute care beds will be completely overloaded by mid-April, if we don’t act now.

Here’s the calculation:

Full disclosure: not an epidemiologist, no fancy calculations, just simple math done around midnight before trying to go to bed.

Confirmed cases

As of March 12, 2020, there are 14 confirmed cases in San Francisco. The whole United States has a total of 1,329 confirmed COVID-19 cases and 38 deaths.

However, there was, and possibly still is, a shortage of testing kits, so the confirmed cases may be underestimated. For the sake of this calculation, let’s just assume that 14 cases is accurate.

COVID-19 cases double every 4–5 days in China in the early phase. In this model using data from more countries, half of the time the doubling time is 2 days. Let’s again, for the sake of simple, back-of-the-envelope calculation, say a doubling time is 3 days for San Francisco.

Based on the calculation, in one month we will have 14,336 confirmed cases. By April 17, 2020, we will have 57,344 confirmed cases.

Figure 1 Projected confirmed COVID-19 cases in SF based on assumptions

Hospitalization needs

According to WHO report, 80% of infections are mild or asymptomatic, 15% are severe infection, requiring oxygen and 5% are critical infections, requiring ventilation, so let’s say 20% confirmed cases need hospitalization.

Not all patients are diagnosed at the same time, and not all confirmed cases need hospitalization at the same time. For the sake of a simple, back-of-the-envelope calculation, let’s assume all the 20% of confirmed cases need hospitalization after 6 days.

According to an NEJM article, the median duration of hospitalization was 12.0 days (mean, 12.8).

Based on these data and assumptions, by April 14, 2020, San Francisco will have 1,434 cases requiring hospitalization, 2,868 by April 17, and 5,735 by April 20.

Figure 2 Projected COVID-19 cases requiring hospitalization in SF based on assumptions

Hospital beds

Now the question is, how many beds do we have in San Francisco?

According to this report by California Health Care Foundation, Bay Area has 202.8 beds per 100k population as of 2014.

It’s worth noted that: 1) this is the data for the Bay Area, not San Francisco city. 2) it is possible that more beds have been added since 2014. Give or take, let’s assume the two factors neutralized each other.

San Francisco has 883,305 residents as of 2018. Therefore, we can assume San Francisco has about 1,790 acute care hospital beds.

Based on the same report, the occupancy rate for licensed acute care beds is 44.4%. Therefore, under normal circumstances, San Francisco has about 996 acute care hospital beds available.

How long can SF’s healthcare system last in the COVID-19 outbreak?

Based on our back-of-the envelop calculation, the result does not look good.

Figure 3 SF hospital acute care beds will be completely overloaded by mid-April

Again, this calculation was based on available data and lots of assumptions, hence may be flawed. However, changing the numbers in the assumptions will only move the dates earlier or later. It doesn’t drastically alter the big picture.

If this really happened, not only thousands of people will either be treated in the hallway, or die at home while waiting for a bed in the hospital.

Just like what’s happening in Italy. According to this twitter user describing what his friend was seeing in Italy:

Did China have the same problem? Yes. Lots of people died at the beginning.

How did China solve the problem? By building two hospitals with 2,500 beds in 10 days, and then another 13 hospitals with 13,348 beds by February 21, 2020, to supply one city; by sending more than 30,000 healthcare workers to support one province.

The two hospitals under construction at that time. (Photo from internet)

Now, do we have the confidence that San Francisco city, or the United States, can make any of these happen?

We haven’t even talk about how vulnerable our first responders and healthcare workers are without proper protective equipment, and whether we are going to have enough doctors or nurses available by that time…

What shall we do?

First, protect yourself and people in your life:

Take good care of yourself. Stay home and do not go out unless it’s ABSOLUTELY NECESSARY. Practice good hygiene. Wash your hands frequently and thoroughly as if you have just touched poop every time you touch something that you are not sure has been sterilized. Sterilize anything you touch every time coming home (e.g., phone, keys, wallet).

Just us acting is not enough. We also need the government to act now. Please call your local representatives and plead the following:

Ban all non-essential gatherings more than 5 people; Force indoor public areas or retail places (TSA, banks, grocery stores, etc.) have hand sanitizer available, employees wear mask and gloves; Shut down all non-essential activities, such as entertainment (e.g., movie theaters).

You may find the contacts of local representatives here: https://sfbos.org/roster-members. If you don’t know which district you are at, you can look here: https://sfplanninggis.org/SFFind.

Let’s act now before we start losing friends and family. Let’s act now before someone starts losing friends and family.