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At least 822 people in Colorado have gotten COVID-19 twice, CDPHE says

Experts have said that while COVID-19 reinfection is rare, natural immunity can wane over time.

DENVER — The Colorado Department of Public Health and Environment (CDPHE) has updated its data dashboard to reflect second infections of the disease caused by the novel coronavirus.

As of Monday afternoon, health officials said 822 people in the state have tested positive for COVID-19 twice more than 90 days apart, representing 0.19% of Colorado’s total case count, which was at 429,839 as of this writing.

The people who have gotten COVID-19 more than once ranged in age from one to 101 years old and lived in 45 of Colorado’s 64 counties. Their median age is 42 years old and 49% of them are female, CDPHE said.

The second cases were reported between Aug. 20, 2020 and Feb. 28, 2021. 

Scientists have said that natural immunity to the novel coronavirus wanes over time, but that reinfection is relatively rare.

> Video above: 9Health Expert Dr. Payal Kohli explains how COVID-19 reinfection occurs. 

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The Centers for Disease Control and Prevention (CDC) defines a second infection as two positive molecular amplification tests separated by 90 days or more. 

This is what's reflected in CDPHE's data, but it's harder to definitively prove a second infection. This requires actually sequencing samples of both tests to determine if the virus on the samples is genetically different. 

So far, the state lab has successfully sequenced seven different pairs of test results to determine true reinfection. Five of those seven were genetically different, and two were not.

Part of the difficulty in making determinations of second reinfection comes from the fact that the latter case typically has a lower viral load, CDPHE said.

“It’s important to note that the criteria used to define a new case or reinfection may change as we learn more about how long immunity lasts,” CDPHE said. “While reinfection is rare, it’s not unexpected based on what we know about similar viruses.”

The first case of COVID-19 in Colorado was confirmed a year ago. 

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