13,000 Cases of Monkeypox Worldwide

It's July 16, and we're now at 13,000 cases of Monkeypox world wide. This means that we're 1,000 cases ahead of what I predicted four days ago. This sets the current rate of doubling at 12 days rather than the 16 that I predicted.

I was too optimistic about the slowdown in doubling rates. We're not yet at the point where these rates slow down rapidly, and we need to revise our predictions.

Sticking with our predictions, the doubling rate should continue to fall, and we can make the following predictions as to the number of cases we're likely to have going forward.

• July 20 - doubling rate at 13 days = 16,000 cases
• July 24 - doubling rate at 14 days = 19,500 cases
• July 28 - doubling rate at 15 days = 23,500 cases
• August 1 - doubling rate at 16 days = 28,000 cases

Looking at the latest numbers from Portugal, we see that there were 515 cases in that country on July 13. That compares to 415 cases on July 1 and 473 cases on July 7. The increase in the six days from from July 1 to July 7 was 54 cases. The increase in the six days between July 7 to July 13 was 42 cases. We've dropped from an increase of 14% every 6 days to an increase of 8% every 6 days.

An increase of 8% every 6 days translates to a doubling in cases every 54 day. Portugal is therefore unlikely to reach as much as 1000 cases by September 1. If the doubling rates continue to fall at their present rate, Portugal may never reach 1000 cases. With a population of 10 million people, Portugal will top out with one in 10,000 people having caught the bug, and with zero deaths.

Assuming that the rest of the world is no different from Portugal, we can predict a similar trajectory everywhere else, and we can conclude that Monkeypox will never become a widespread disease.

Experience from Portugal tells us that once we reach a doubling every 16 days, the growth rate slows down dramatically. If current projections hold, we'll see this happen worldwide starting August.

Monkeypox, cumulative cases, linear plot

By Edouard Mathieu, Saloni Dattani, Hannah Ritchie and Max Roser (2022) - "Monkeypox". Published online at OurWorldInData.org. Retrieved from: https://ourworldindata.org/monkeypox [Online Resource] - https://ourworldindata.org/monkeypox, CC BY 4.0, Link