Coronavirus Cases

Giving lectures online is so different from teaching inside a classroom. That is still an understatement. These are difficult times for teachers and students. Yesterday, I received a note from one of my students that made me feel both happy and sad:
Also, we all miss you a lot, too. It's not the best situation, but at least we still get to study chemistry, even if it is from home.
My students are indeed still studying chemistry. And we could hope that they are still learning. But it is hard to focus on the material with so much going on outside. After all, it is not just the health status that we worry, but also the economy. I am currently covering kinetics in my General Chemistry class. This is the study of how fast chemical reactions occur so I could not avoid the fact that we are dealing with an unsettling dynamic situation in the world. This is how I started my lecture yesterday:


Right now, we have these questions regarding the corona virus. How fast does it spread? How does it spread? To answer these questions, we may look at specific instances or cases. One huge problem we have at the moment is that we do not have an accurate snapshot of who has been infected in the entire population. We do not have an accurate number of how many have been infected. The rise in the number of cases we are seeing may just be a reflection of how fast we are testing. Thus, we do not really have an idea of the rate of infection. Before we can begin studying what factors affect the rate of infection, we need to measure the rate first. It is only after we know how fast it is spreading can we start looking for clues, for example, where most of the transmission is occurring. Are these happening in restaurants, in work places, in our homes, or in our schools? But we have to exercise interventions now to slow down the epidemic. There is really no time to study the kinetics of COVID-19 because we must act now.

Back in March 3 when the number of known cases in Italy was about 38 per 1 million people, the city of Vo did a mass testing of all its 3300 inhabitants. They found 2.7 percent positive with the corona virus. The current situation in the US is about 27 known cases per 1 million people, similar to the time when the mass testing was done in Vo, so it is reasonable to suggest that at this point, the US has a similar infection rate 2.7%. This implies that there are probably 27,000 cases now per 1 million people. And currently, we only know 27, this is three orders of magnitude, indicating how so many cases are really asymptomatic. So, with the current count of 9,000, there could be 9,000,000 cases already. I hope this math is wrong.

It is clear that testing severely lags the actual number of cases of COVID-19. Perhaps, what is more reliable to analyze is the number of critical or serious cases known. Although the severity of COVID-19 is dependent on the age of the individual and the age distribution is not perfectly homogeneous around the world, the error in these numbers is probably less than an order of magnitude. Working along this line of reasoning and extending what is already known with regard to how serious cases have grown in China, one arrives at the following extrapolation. The number of serious cases will hit a peak about 18 days from now, on April 3. The peak will be about 18,000 cases. This is more than twice the number of serious cases at the moment.

Above graph, modified from Coronavirus Update 

The above is a very rough extrapolation. I am not from the Imperial College in UK, but it paints a much more optimistic scenario. We can only hope.