What you need to know about R-0

The R-0 of a virus is also known as the Reproductive Rate. This number is the number of people that a person with the illness infects. With an R-0 of <1, illness is considered to be under control or decreasing. With an R-0 of >1, the illness is spreading. The following table is a comparison of common viruses with known R-0 to the limited information we have of COVID-19. As of March 16, 2020, the WHO estimates an R-0 of between 2.2 and 6.48. The CDC confirmed that there are 2 different strains of the virus. Once the strains have separate tests, we will be able to determine a more precise R-0 number for each one.

Maybe Dr. Mears (Kate Winslet) explains it better:

Check out a more detailed mathematical modeling here:

Early Dynamics of transmission and control of COVID

You should also check out:

6 thoughts on “The R-0 of COVID-19 compared to other Viral Outbreaks”
  1. I think you are asking if Ebola kills more people that COVID-19 but you could also be asking if Ebola kills more than coronaviruses (SARS, MERS and COVID-19) so I will try to answer both questions.

    1. Ebola has killed a total of 13,562 people since it was identified in 1976. You can pull up all the outbreaks of Ebola and look at how many people it has killed each time at the CDC- https://www.cdc.gov/vhf/ebola/history/chronology.html

    2. COVID-19, has killed a total of 3,460 (as of March 6 at 1 pm) All coronaviruses combined have killed a total of 14,052 (MERS 2,494, SARS 8,098 and COVID-3460)

    So, Coronaviruses combined have already killed more people than Ebola but it is more complicated than that.

    Ebola has been around since 1976. This means it has killed about 308 people a year for the past 44 years.

    SARS, MERS and COVID-19 have only been around since the SARS outbreak in 2002. So that means that they have killed about 781 people a year for the past 18 years.

    We also have to look at the fact that COVID-19 has killed 3,460 people in the past 65 days which is about 53 people a day. This means that if it was to persist for 1 year at this rate, the total deaths can be extrapolated to be 19,398 people this year (a leap year)

    So it is hard to answer the question but only time will tell.

    1. Currently COVID has about 2,200 new cases every day. With a total of about 100,000 cases in the past 2 months, it comes out to about 1 person is being infected every minute. You can look at the math which is continuously updated using the CDC and WHO numbers at http://www.georgiastem.com/covidmath

    1. Ok- So we will deal with each of your questions:
      1. Is the R-0 going up or down?
      Honestly, we have no idea. We know this is not reassuring but we also don’t want to just make something up. We have been tracking the numbers on our post COVID Math and we are finding that the number of infections is up slightly from last week. It is now around 84 people an hour and a little over 1 a min. This is not typical if the R-0 was going down. But beyond that- it is all speculation.

      2. How did the new strain change the data?
      It looks like the new strain is more infections and spreads easier than the original strain but again- all speculation because the N-value is still too low. We will know more in a couple of weeks.

      3. Do the strains have different tests?
      No- in fact, the initial test was not even developed for COVID specifically. The quick test just picks up on coronaviruses in general. The more expensive and more precise tests at the CDC do test for COVID specifically but they are not releasing if they are looking at the different strain data. I am sure they are collecting that but it is not public.

      Thank you for the questions. Did that help? Just reach out again if you need more information or clarification.

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