Georgia > How many people in Dekalb / Fulton *actually* have had COVID?

The CDC recently released a report that goes into detail on a study conducted from April 28 - May 3 to understand how many people in Dekalb and Fulton might actually have had COVID-19. They did this by conducting a special kind of survey to determine the prevalence of the virus -- essentially "how many people have or have had the virus".

COVID Antibodies

The results? They estimated the prevalence of the virus in those two counties is around 2.5%. What this basically means is as much as 2.5% of the county populations have  COVID antibodies in their system.

So, knowing this, a bit of simple math:

Fulton's population is 1,050,110 and Dekalb's population is 756,558. With a prevalence of 2.5% this means as many as 18,931 people in Dekalb had the virus and 26,253 people in Fulton had the virus when the study was completed on May 3rd.

If you work backwards from the prevalence and the known cases on May 3rd (2184 cases for Dekalb and 2981 for Fulton) you can deduce that for every reported case, there were approximately 8.6 cases in Dekalb and 8.8 in Fulton. Is the factor still 8.6 and 8.8 respectively? At this point we can only guess but since Georgia hasn't really moved much over the last few months in testing, it's reasonable to assume the factor is roughly the same.

Note: As of this writing on July 21 Dekalb has 9,800 reported cases and Fulton has 13,379 reported cases

A few caveats about this

  1. This study was conducted almost 3 months ago. A lot has changed.
  2. The study identified people who *have* antibodies for the virus.

You can read a great NYTimes article about the study here or you can ready the actual CDC paper here.

A little more detail on how the study was conducted

  • 396 households and 694 individuals participated
  • A representative sample of census blocks was selected to accurately represent the makeup of the counties
  • No children were found with COVID antibodies
  • The highest rate among racial / ethnic groups with COVID antibodies was non hispanic blacks with a prevalence of 5.8% (that's more than double the prevalence for all groups)

Data like this does a great job of helping us understand how widespread COVID-19 actually is.

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