Would Houston’s antibody testing study change current death rate?

HOUSTON – Is the coronavirus death toll in the city of Houston much lower than what’s being reported?

KPRC 2 is taking a new look at the data following the results of the cities antibody survey. Earlier this week, the city of Houston released the results of its program that involves taking blood samples from people and random Houston area homes.

They estimate 250,000 people have been infected with the coronavirus as of mid-September. When traditional viral testing had the number of infected people at just 57,000.

Of course, the city’s death toll has not experienced such a major change. That would mean, with many more cases, the death rate is smaller than previously thought.

But health officials said the answer to that is no, it will not change the death rate. City of Houston Health officials said it’s complicated, but it comes down to two different metrics: the case fatality rate and the infection fatality rate.

Dr. David Persse, director of emergency medical services for the city of Houston, said the recent antibody study across the city tested willing families for COVID-19 antibodies.

It was done to see how many people were really infected with the virus and survived.

Here’s what the study found:

- 13.5% of Houstonians previously had COVID-19 by September 19. That’s approximately 250,000 people.

- Only 57,000 infections were identified at the time by traditional viral testing.

- It also showed more women than men had it and more Hispanics and Blacks had the antibodies than whites.

- 18% of Hispanics and 15% of Blacks had antibodies than non-Hispanic Whites at 5%.

But will all this new data showing more people had COVID-19 but survived, will that change the death rate? Dr. Persse says no.

“An infection fatality rate is when you know everybody who got infected and how many of them died. A case fatality rate, you know of the cases that you know of and how many died recognizing there’s a whole bunch more cases you don’t know of,” Persse said.

“With this, we have an idea. We have a pretty good estimate of the total number of people who were infected and know how many died. An infection fatality rate is always going to be much much much lower than case fatality rate because there are more people infected than you know of,” Persse added.

Dr. Elaine Symanski, from the Department of Medicine at Baylor College of Medicine, was also part of this prevalence study. She said the data shows that more people had it and may not have known. Symanski said many people are still at high risk of getting COVID-19.

“There are still a lot of individuals who again are at risk for exposure which means we can’t let our guard down,” Symanski said.

Persse said the new data will change the infection fatality rate.

They are recalculating those numbers now and will get out those answers soon.

But again, Persse said the death rate that is reported daily, also known as the case fatality rate, that will not change.

“Now we know there were more cases we need to go back and recalculate the actual infection fatality rate and that’s being done now we will get that answer fairly soon,” Persse said.

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