Warning: This analysis contains the results of a predictive model. There are a number of assumptions made which include some speculation. Furthermore, this analysis was not prepared or reviewed by an Epidimiologist. Therefore, the assumptions and methods presented should be scrutinized carefully before arriving at any conclusions.

Estimated Infected Population By Country

with respect to days since outbreak

Tip: Click (Shift+ for multiple) on countries in the legend to filter the visualization.

Latest Country Estimates

Date Estimated Infected Lower Bound Estimates Upper Bound Estimates
Country
Brazil 2020-04-27 119,972 92,286 171,389
China 2020-04-27 83,986 83,918 119,980
France 2020-04-27 182,312 165,963 260,446
Germany 2020-04-27 170,589 158,758 243,699
Iran 2020-04-27 100,995 91,472 144,278
Italy 2020-04-27 219,599 199,414 313,712
Japan 2020-04-27 18,451 14,193 26,358
Portugal 2020-04-27 27,725 24,027 39,607
Singapore 2020-04-27 23,641 18,186 33,773
South Korea 2020-04-27 10,840 10,752 15,486
Spain 2020-04-27 265,741 229,422 379,630
United Kingdom 2020-04-27 203,946 158,348 291,352
United States 2020-04-27 1,272,243 988,197 1,817,490

Infected vs. number of confirmed cases

Allows you to compare how countries have been tracking the true number of infected people. The smaller deviation from the dashed line (45 degree line) the better job at tracking the true number of infected people.

Tip: Click (Shift+ for multiple) on countries in the legend to filter the visualization.

Latest Observed vs. Estimate of Infected Cases

Date Observed Cases Estimated Infected
Country
Brazil 2020-04-27 67,446 119,972
China 2020-04-27 83,918 83,986
France 2020-04-27 165,963 182,312
Germany 2020-04-27 158,758 170,589
Iran 2020-04-27 91,472 100,995
Italy 2020-04-27 199,414 219,599
Japan 2020-04-27 14,153 18,451
Portugal 2020-04-27 24,027 27,725
Singapore 2020-04-27 14,423 23,641
South Korea 2020-04-27 10,752 10,840
Spain 2020-04-27 229,422 265,741
United Kingdom 2020-04-27 158,348 203,946
United States 2020-04-27 988,197 1,272,243

Methodology

We argue that the number of infected in the past can be inferred using today's number of deaths and average fatality rate from confirmed cases in the following way:

$$I_{t-j} = \frac{D_t}{{CFR}_t}$$

where $I_t$ = number of infected, $D_t$ = number of deaths, and ${CFR}_t $ = case fatality rate = $\frac{D}{C}$. The $j$ depends on the average number of days that covid patients die after having the first symptoms.

Assumption 1: The case fatality rate is a good proxy for the fatality rate of the infected population

Then, in order to estimate the current number of infected $I_t$ we need to estimate its growth rate from $t-j$ to $t$.

$$I_t = (1+\hat{g})^j I_{t-j}$$

Assumption 2: The growth rate of infected $\hat{g}$ is an unbiased estimate of $g$ .

For now we estimate $g$ using the average growth rate since having the first infected person.

Assumption 3: It takes on average 8 days to die after having the first symptoms.

This analysis was conducted by Joao B. Duarte. Relevant sources are listed below:

  1. 2019 Novel Coronavirus COVID-19 (2019-nCoV) Data Repository by Johns Hopkins CSSE GitHub repository.

  2. Feenstra, Robert C., Robert Inklaar and Marcel P. Timmer (2015), "The Next Generation of the Penn World Table" American Economic Review, 105(10), 3150-3182