## COVID-19 (Coronavirus) Outbreak Tracker

This page tracks several important factors of the ongoing coronavirus outbreak.

Two important factors to determine for the novel coronavirus (SARS2CoV) are the case fatality rate (CFR) and the R-nought (R0) value of the virus. The current estimated values for the coronavirus are plotted in the graph below - along with those values for several past outbreaks for comparison.

The CFR calculation used is based on cases from countries who scored at least 50 out of 100 on the 2019 Global Heath Security Index's measure of their ability to detect and report emerging epidemics. Note this excludes data from mainland China. Although this excludes a significant amount of cases, it is arguably more accurate given that Chinese data is particularly unreliable. This exclusion also allows us to factor in a greater proportion of mild and asymptomatic cases that the included nations are best able to detect.

The R0 value is the weighted average from collected pre-print studies (studies with calculations based on newer data are weighted higher). A few other graphs, some interesting relevant studies, sources and calculations, and a rational for the chosen CFR methodology are further down on the page.

Current Estimate:

CFR: 5.52% (5.10% - 5.94% Confidence Interval: 95%)

R0: 3.66 (Lowest range from study R2, Highest Range R6.6)

Updated: 2/20/20 12:20pm EST

Another useful data point is the trend in confirmed cases detected outside of mainland China. We can see that this trend is still increasing.

Updated 2/18/20

It is also worthwhile to watch the level of quarantine and lockdowns in China. As of February 15th it was estimated that some 760 million people in China are under some form of lockdown. Check out the excellent map below (Source) which is the best visualization I've seen of the extent of the lockdowns in China.

Please feel free to contact me with any new relevant studies I've missed or thoughts on my approach!

Sources and Calculations

R0 Values:

The weighted average R0 value is the average R0 values of the studies below, with each study weighted to lose 2% for each day earlier than the latest published study. E.g. a study based on data from 1/22/20 would be weighted 30% less than a study with data up to February 5th (15 days)

Novel coronavirus 2019-nCoV: early estimation of epidemiological parameters and epidemic predictions

Transmission dynamics of 2019 novel coronavirus (2019-nCoV)

Report 3: Transmissibility of 2019-nCoV

Early Transmissibility Assessment of a Novel Coronavirus in Wuhan, China

The Novel Coronavirus, 2019-nCoV, is Highly Contagious and More Infectious Than Initially Estimated

Epidemiological and clinical features of the 2019 novel coronavirus outbreak in China

CFR Calculation:

CFR calculation is a simple ratio of the number of cases from countries who scored at least 50 out of 100 on the 2019 Global Heath Security Index's measure of their ability to detect and report emerging epidemics which have resulted in either recovery or death. Source for recoveries and deaths.

CFR calculation is e2(s)=D(s)/{D(s)+R(s)} where, D(s), R(s), and C(s) denote the cumulative number of deaths, recoveries, and cases, respectively. Why use this methodology? Firstly because of the unreliability of the data from mainland China adds uncertainly to other statistical calculations, Moreover studies on calculating the CFR in the SARS epidemic showed that this approach was "reasonable at most points in the epidemic" although it briefly underestimated the true CFR at one point.

Confidence Interval and Margin of Error calculated by:

n = [z2 * p * (1 - p) / e2] / [1 + (z2 * p * (1 - p) / (e2 * N))]

Where:

n is the sample size,

z is the z-score associated with a level of confidence,

p is the sample proportion, expressed as a decimal,

e is the margin of error, expressed as a decimal,

N is the population size.

Daily and Cummulate Infected Numbers from the John Hopkins CSSE Tracker

Additional Interesting Studies:

The role of absolute humidity on transmission rates of the COVID-19 outbreak

Estimating case fatality ratio of COVID-19 from observed cases outside China

Clinical Characteristics of 138 Hospitalized Patients With 2019 Novel Coronavirus–Infected Pneumonia in Wuhan, China

Estimating underdetection of internationally imported COVID-19 cases