Why No One Knows How Many Coloradans Have COVID

The Colorado Department of Public Health and Environment's regular COVID-19 updates have documented recent average daily case counts of between 5,000 and 10,000. But the agency admits that these amounts don't come anywhere close to reflecting the total number of infections.

"We know there are more COVID-19 cases in Colorado than we are able to capture in our daily case counts," acknowledges Brian Spencer, spokesperson for the state's joint information center, which is handling communication about the disease for the state. "Some people who are infected with COVID-19 may not get tested, as they may be asymptomatic or only display minor symptoms."

That's only the beginning of the uncertainty. Rapid tests are more widely available in Colorado than in many other states around the country, owing in part to a state program to provide them for free to any resident, including the parents or guardians of school-age children. And people who score positive on rapid tests often begin the five-day quarantine or isolation period currently recommended by the Federal Centers for Disease Control and Prevention without informing the CDPHE.

Spencer wishes the department would receive a heads-up more often. "We want individuals to report their positive rapid at-home results," he explains, "because it helps us obtain important information about possible close contacts and provide important information about possible treatment options and guidance for isolation and quarantine."

Even if they do notify the CDPHE, however, Spencer says that their cases won't automatically be added to the overall count: "Individuals who test positive with a rapid at-home, over-the-counter test are classified as suspect cases unless they receive additional testing or public-health investigation. These individuals are not included in our daily case counts, which only include confirmed and probable cases."

In other words, the department would like people who register positive on a rapid test to then take a PCR test, which is much more accurate. But even though such tests can be obtained at a wide variety of locations, including more than 150 free community sites supported by the CDPHE, this extra step may strike many people with minor symptoms as an unnecessary waste of time. After all, PCR results have been taking two or three days to come back, by which time an individual's quarantine or isolation time is almost over.

To compensate for what are likely many thousands of unreported COVID cases, Spencer stresses that the state health department uses "multiple metrics to help us have full situational awareness about trends across the state, including percent positivity, hospitalization trends and modeling data." On January 26, for example, the state estimated that one in every nineteen Coloradans is infected with COVID. Since the start of the pandemic in March 2020, the total number of official COVID-19 cases counted in Colorado as of January 28, the most recent date for which the CDPHE has reported data, stands at 1,240,361.

Spencer confirms that "self-reported results are not included in the statewide test positivity rate," which of late has typically exceeded 20 percent, more than four times higher than the 5 percent level that health officials want to stay under. "The statewide test positivity rate includes PCR and other molecular assay tests only," he notes. "We do not include reported at-home positive results as part of this metric, because we do not receive reports of all results of at-home tests — positive or negative — so we do not have a denominator of total tests administered to use to calculate percent positivity."

Those who test negative on an at-home test but are exhibiting symptoms should take a PCR test, Spencer says. And he encourages anyone who tests positive on a rapid at-home test to isolate immediately, adding that they "do not need to get additional testing. They should contact people they have recently been around to let them know they may have been exposed. They can also enter their positive test result into the exposure notification system to notify potential contacts anonymously."

To report test results, see the CDPHE's rapid at-home antigen test guide.