Second-infection cases now on dashboard

Colorado Department of Public Health and Environment has added 822 cases to the data dashboard that meet the standard national criteria to define persons who had a second infection of the virus that causes COVID-19.

The cases have report dates of Aug. 20-Feb. 28, and represent 0.19% of Colorado’s total count. Cases have a median age of 42 and are distributed among 45 Colorado counties.

The criteria the Centers for Disease Control and Prevention uses to define persons with a second infection is two positive molecular amplification tests, such as a PCR test, separated by 90 days or longer.

The measure of whether the two tests actually represent two different infections, as opposed to one continued infection with intermittent shedding of the virus, is whether they are genetically different from each other. However, it is rarely possible to make this definitive determination due to availability of specimens.

A lab needs access to the first and second samples to perform genetic sequencing. Because most labs don’t keep samples for more than a few days, the state lab is unable to sequence for the vast majority of these cases. Additionally, extended storage can reduce the quality of a specimen and second infections often have lower viral load, affecting the ability to perform genetic sequencing.

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