The Covid-19 Pandemic May be Over Sooner Than You Think

Covid-19 has spread throughout the world and people and governments are going to extraordinary lengths to contain it.

Two of the first nations to experience the pandemic are China and South Korea. In both cases, the number of new casualties has dropped ( in China there have been no new cases at all yesterday – 23-March 2020). In other countries, including Canada and the U.S., the number of new cases is still rising.

We can look at the data for Canada and the U.S. and compare it to South Korea and see if there are similarities and if it can suggest how long the outbreak will last.

The figure below shows that cumulative number of cases in the three countries, as provided by John Hopkins University (via the Globe and Mail):

To compare the graphs, two adjustments need to be made:

• Shift the time for each so that they all start at the same time
• Scale the numbers to account for the differences in population and extent of the affected areas.

The result, with a little bit of adjustment of the scaling factor, is shown below:

The match is uncannily close, implying that the trajectory in each country is very similar.

On these plots, the peak infection rate is when the curve is steepest. When it starts curling over, the number of new cases is decreasing.

Canada looks like it is close to the peak infection, and within a few days the number of new cases will start declining, becoming negligible in 20-30 days.

The U.S. is lower on the curve. It has about 10-15 days before it reaches peak infection and then 20-30 days before it subsides.

Some caveats:

• South Korea is a small compact country. The U.S. and Canada are large. It is quite likely that different parts of the U.S. and Canada will experience their own peak infections at different times, extending the overall picture.
• The three countries have taken different steps to mitigate the spread of Covid-19. The effect of these differences is unknown and not taken into account n this analysis.

This view is shared by others. For example, I quote from an article from the Times of London (“Don’t panic, we’ll be fine, scientist tells the world”, March 23, 2020):

“A Nobel laureate scientist who correctly predicted that China would control the corona virus far more quickly than original estimates predicted said yesterday that the world was “going to be fine” but “what we need to control is panic”.

Michael Levitt, a biophysicist at Stanford University, said that data on the outbreak of the virus does not support predictions of years of disruption and millions of deaths worldwide.

Professor Levitt, who won the Nobel prize for chemistry in 2013, said even countries that had not imposed such strict lockdowns as China were already showing signs of recovery. “Numbers are still noisy but there are clear signs of slowed growth [of the virus],” he said.”